UBC Theses and Dissertations

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UBC Theses and Dissertations

On the behaviour and evolution of American mountain sheep Geist, Valerius 1966-10-04

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The U n i v e r s i t y of B r i t i s h Columbia FACULTY OF GRADUATE STUDIES PROGRAMME OF THE FINAL ORAL EXAMINATION . FOR THE DEGREE OF DOCTOR OF PHILOSOPHY of VALERIUS GEIST B . S c , U n i v e r s i t y of B r i t i s h Columbia, I960- FRIDAY, OCTOBER 28, 1966 AT 3:30 P.M. IN ROOM 3332, BIOLOGICAL SCIENCES BUILDING COMMITTEE IN CHARGE , Chairman:. • I. McT. Cowan D. C h i t t y • VI. S. Hoar D..J. Randall ...... . .V." J . K r a j i o a II. D. F i s h e r . W. D. K i t t s - E x t e r n a l Examiner: , . -A. S. Leopold U n i v e r s i t y of C a l i f o r n i a • Berkeley Research Supervisor:.. I . McT. Cowan OS THE BEHAVIOUR AND EVOLUTION OF AMERICAN MOUNTAIN SHEEP ABSTRACT The aim of t h i s study was to d i s c o v e r the r u l e s of s o c i a l behaviour of sheep and to e x p l a i n the s e l e c t i o n f o r c e s r e s p o n s i b l e f o r t h e i r e v o l u t i o n . Three populations of f r e e l i v i n g sheep (Ovis d a l l i s t o n e i , o.d„ d a l l i , & o. canadensis canadensis) were s t u d i e d d u r i n g a l l seasons. Their behaviour was described. Each s o c i a l i n t e r a c t i o n was t r a n s f e r r e d to a computor card; 3SOO i n t e r a c t i o n s were analysed and form the b a s i s of the q u a n t i t a t i v e data reported. The evolu t i o n of mountain sheep i s conceived as f o l l o w s : Sheep evolved from a r u p i c a p r i d ancestor who innovated a new defense mechanism a g a i n s t hornblows of c o n s p e s i f i e s . The blows were caught w i t h the horned head which l e d to the e v o l u t i o n of pneumated s k u l l s , t h i c k f a c i a l s k i n and h e a v i e r horn b a s i s . The g e n e r a l i s e d , damaging combat form of the r u p i - c a p r i d s was replaced by a r i t u a l i s e d f i g h t , i n which opponents c l a s h head on w i t h l i t t l e damage to each other. This i s one p r e r e q u i s i t e to the formation of a dominance h i e r a r c h y . Horns became not only weapons but a l s o s h i e l d s and u l t i m a t e l y d i s p l a y organs and rank symbols. • The mechanism which i s r e s p o n s i b l e f o r the development of l a r g e horns, appears t o be neoteny. The ram remains " j u v e n i l e " i n c h a r a c t e r f o r 5-6 years past sexual maturation. This concept e x p l a i n s t h e i r prolonged b e h a v i o u r a l and b o d i l y maturation, the increased sexual dimorphism, the intense gregariousne of rams p r i o r to u l t i m a t e m a t u r i t y , the independence and l e a d e r s h i p of matured rams, the disappearance of neck r u f f s i n advanced sheep and the d i f f e r e n c e s i n aggressive behaviour between bighorn and t h i n horn sheep. Females are paedogenic i n t h a t they can only reach a developmental stage i n appearance and be haviour s i m i l a r to y e a r l i n g rams. Hence, there i s no d i s t i n c t female "form" i n sheep. I n c o r r e l a t i o n we f i n d that rams have no d i s t i n c t behaviour shown only to females, r a t h e r they t r e a t females and subordinate rams i n almost i d e n t i c a l manner. Con v e r s e l y , subordinate males may behave l i k e females,$ towards dominants. The s o c i a l behaviour of a d u l t rams f a l l s i n t o two c a t e g o r i e s , t h a t of the dominant and t h a t of the subordinate; the non-estrous ewe a c t s l i k e a s e x u a l l y immature j u v e n i l e . When i n estrus the ewe changes behaviour- a l l y i n t o a young, subordinate male. This e x p l a i n s why ewes i n the non-estrous s t a t e form un i s e x u a l bands and a l s o why they are more gregarious than rams. The neotenic characters of sheep appear to be a by product of s e l e c t i o n f o r l a r g e horns. Sheep evolved r a p i d l y whenever they c o l o n i s e d new h a b i t a t i n the wake of r e t r e a t i n g g l a c i e r s . They increased i n horn and body s i z e , sexual dimorphism, rumppatch s i z e and legmarking, and reduced or l o s t the n e c k r u f f s ; c o n c u r r e n t l y they s p e c i a l i s e d i n c l a s h i n g and replaced the broadside w i t h a horn d i s p l a y . Large horns and s p e c i a l i s e d c l a s h i n g were adaptive i n the c o l o n i z i n g , expanding p o p u l a t i o n s , i n which rams had a r e l a t i v e short l i f e expectancy. S e l e c t i o n f o r these c h a r a c t e r i s t i c s came to a h a l f i n the s t a b l e populations when l i f e expectancy of rams increased w h i l e horn and body s i z e decreased. This concept e x p l a i n s the d i n e s of A s i a t i c and American sheep. In t h e i r e v o l u t i o n , sheep changed,apparently p r i m a r i l y i n s o c i a l adaptations. H a b i t a t ' - body care - and s o c i a l behaviour evolve l a r g e l y independently of each other. GRADUATE STUDIES F i e l d of Study: Zoology Ethology L, von Haartman:: W. S. Hoar M- D. F. Udvardy J . F. Eisenberg Mammalogy I.- McT. Cowan PUBLICATIONS G e i s t , V. 1959. D i u r n a l a c t i v i t y of moose. Memo. Soc. Fauna & F l o r a Fennica. 35". 95-100., I960, F e r a l goats i n B r i t i s h Columbia. M u r r e l e t kl (3) : 1-7- 1963. On the behaviour of the North American moose (Alces a l c e s ' andersoni Peterson 195°) i n B r i t i s h Columbia. Behaviour 20.(3-U): 377- kl6. 1965. On the r u t t i n g behaviour of the mountain goat. Mammalogy. U5(U): 551-568. 1966. V a l i d i t y of hornsegment counts i n aging bighorn sheep. J.Wild. Mgmt. 1966. E t h o l o g i c a l observations on some North American Cervids. Z o o l . B e i t r a g e 12: ZL9-25O. 1966. The e v o l u t i o n of h o r n - l i k e organ: Behaviour ( i n press) 1966. Tiie e v o l u t i o n a r y s i g n i f i c a n c e of mountain sheep horns. E v o l u t i o n ( i n press) 1966. On f i g h t i n g i n j u r i e s and dermal s h i e l d s i n mountain goats. J . W i l d l . Mgmt. ( i n press) I . McT. Cowan and V. G e i s t . 1961. Aggressive be haviour i n deer of the genus Odocoileus. J . Mammal. k2(k): 522-526. 30" (3): 634-635. O N T H E B E H A V I O U R A N D E V O L U T I O N O F A M E R I C A N M O U N T A I N S H E E P b y V A L E R I U S G E I S T B . S c , U n i v e r s i t y o f B r i t i s h C o l u m b i a , 1 9 6 0 A T H E S I S S U B M I T T E D I N P A R T I A L F U L F I L M E N T O F T H E R E Q U I R E M E N T S F O R T H E D E G R E E O F D O C T O R O F P H I L O S O P H Y i n t h e D e p a r t m e n t o f Z o o l o g y We a c c e p t t h i s t h e s i s a s c o n f o r m i n g t o t h e r e q u i r e d s t a n d a r d T H E U N I V E R S I T Y O F B R I T I S H C O L U M B I A O C T O B E R , 1 9 6 6 I n p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of the r e q u i r e m e n t s f o r an advanced degree at the U n i v e r s i t y of B r i t i s h Columbia., I agree t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and stu d y . I f u r t h e r agree t h a t p e r  m i s s i o n f o r e x t e n s i v e c o p y i n g of t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the Head of my Department or by h i 3 r e p r e s e n t a t i v e s . I t i s understood t h a t , c o p y i n g or p u b l i  c a t i o n of t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n * Department ci The U n i v e r s i t y of B r i t i s h Columbia., Vancouver 8, Canada Date _JLct 2, f r < /f£s_ i i A B S T R A C T B e h a v i o u r s t u d i e s w e r e u n d e r t a k e n o n t h r e e p o p u l a  t i o n s o f f r e e l i v i n g A m e r i c a n s h e e p , o n e b e i n g a S t o n e ' s s h e e p ( O v i s d a l l i s t o n e i ) . o n e a B a l l ' s s h e e p ( 0 . d . d a l l i ) a n d o n e a b i g h o r n s h e e p p o p u l a t i o n ( 0 . c a n a d e n s i s c a n a d e n s i s ) . T h e h a b i t a t - , b o d y c a r e - a n d s o c i a l b e h a v i o u r p a t t e r n s - e x c e p t t h o s e o f m o t h e r a n d y o u n g - w e r e d e s c r i b e d i n d e t a i l . E a c h s o c i a l i n t e r a c t i o n r e c o r d e d w a s t r a n s f e r r e d t o a c o m  p u t e r c a r d . 3 8 0 0 i n t e r a c t i o n s w e r e a n a l y s e d a n d f o r m t h e b a s i s o f t h e q u a n t i t a t i v e d a t a r e p o r t e d . A m e r i c a n s h e e p s h o w o n l y m i n o r q u a n t i t a t i v e d i f f e r e n c e s i n t h e i r s o c i a l b e h a v i o u r . H o w e v e r , b e h a v i o u r a l d i f f e r e n c e s w i t h i n p o p u l a  t i o n s o f . t h e s a m e s p e c i e s o c c u r a n d a p p e a r t o r e f l e c t p o p u l a t i o n q u a l i t y . S h e e p e v o l u t i o n i s c o n c e i v e d a s f o l l o w s : S h e e p e v o l v e d f r o m r u p i c a p r i d a n c e s t o r s . T h e y e v o l v e d l a r g e h o r n s , p n e u m a t e d s k u l l s , l o s t o r r e d u c e d d i s p l a y h a i r s , i n c r e a s e d t h e s i z e o f t h e r u m p p a t c h a n d i n c r e a s e d s e x u a l d i m o r p h i s m . T h e d a m a g i n g f i g h t i n g f o r m s o f t h e r u p i c a p r i d s w e r e r e p l a c e d b y a r i t u a l i s e d f o r m o f c o m b a t . S h e e p l o s t t h e t h i c k h i d e a s a d e f e n c e m e c h a n i s m , a n d d e f e n d t h e m s e l v e s b y c a t c h i n g t h e h o r n b l o w w i t h t h e i r h o r n e d h e a d . S k u l l s e v o l v e d t o a b s o r b c o n c u s s i o n . T h e b r o a d s i d e d i s p l a y w a s r e p l a c e d b y h o r n d i s p l a y s . R a m h o r n s f u n c t i o n n o t o n l y a s w e a p o n s , b u t a l s o a s g u a r d s , d i s p l a y i i i organs and rank symbols. Sheep appear to have evolved rap id l y whenever they co lonized new habitat i n the wake of r e t rea t i n g g l a c i e r s . The expanding populations would experience intense se lec t i on f o r f o r c e f u l c lash ing and l a rger horn s i z e . Large horn s ize i s a funct ion of neoteny i n rams. Rams mature sexual ly at 1.5 - 2.5 years of age, but do not mature behavioura l ly or reach ult imate growth form u n t i l they are 7 - 8 years o l d . Females are paedo- genic forms which remain s im i l a r i n appearance and behaviour to sexual ly mature year l i ng rams. Neoteny also explains the long body growth of rams, the reduct ion and loss of the neck r u f f , increased sexual dimorphism, the intense gre- gariousness of females and of juveni le rams, the increas ing independence and leadership of rams as they grow o lder , and the more frequent use of aggressive patterns by bighorn as compared to th in horn sheep. Rams pre fer to in teract with rams of t h e i r own horn s i ze and with females. They t reat subordinates, i r re spec t i ve of sex, much the same as they t reat females. Rams change t h e i r behaviour not with the sex of the companion but with i t s dominance rank. The more that subordinate rams resemble females in appearance, the more they are t reated sexual ly by dominant rams. Subordinate rams may act l i k e females to the extent of u r ina t ing , or, assuming lo rdos i s when mounted. Non-estrous ewes withdraw i v from rams, but estrous ewes remain and act l i k e subordinate rams. Ewes are guarded and defended singly as they come into heat. They are followed by a group of rams. The largest horned rams guard and mount estrous ewes. Rams fi g h t throughout the years, not f o r females, but f o r dominance. Despite intense competition, the dominant ram takes the estrous ewe away from the subordinate uncontested. Sheep changed primarily i n s o c i a l adaptations, which evolved quite independently of habitat - or body care adapta t i o n s . V A C K N O W L E D G E M E N T S D u r i n g t h i s s t u d y , I h a v e b e e n a i d e d b y m a n y p e r s o n s a n d s e v e r a l o r g a n i z a t i o n s t o w h o m I w i s h t o e x p r e s s m y s i n c e r e t h a n k s . O n t h e S t o n e * s s h e e p s t u d y , m y w i f e a n d I w e r e f r e  q u e n t l y a n d g e n e r o u s l y a s s i s t e d b y M r . a n d M r s . T . A . W a l k e r . D u r i n g t w o w i n t e r s , I r e m a i n e d i n r a d i o c o m m u n i c a t i o n w i t h M r . a n d M r s . W . B . S m i t h a n d M r . a n d M r s . M . H e s s o f N o r t h e r n M o u n t a i n A i r l i n e s , P r i n c e G e o r g e . W i t h o u t t h e i n t e r e s t a n d h e l p o f t h e s e p e r s o n s , t h e s t u d y w o u l d n o t . h a v e b e e n . I w a s a i d e d a l s o b y M r . H e r m a n P e t e r s o n o f A t l i n a n d D r . A . M . P e a r s o n o f W h i t e h o r s e . I n B a n f f N a t i o n a l P a r k , w e w e r e h e l p e d o f t e n b y P a r k W a r d e n s , M r . F . J . C o g g i n s a n d M r . J . C . H o l r o y d . I a m g r a t e f u l f o r t h e c o o p e r a t i o n e x t e n d e d t o m e b y t h e l a t e M r . J . E . S t e n t o n , t h e n W a r d e n o f B a n k h e a d d i s t r i c t a n d M r . N o r m a n T i t h r i n g t o n o f B a n f f . T h e b i g h o r n s t u d y w a s a i d e d b y t h e f r i e n d l y c o - * o p e r a t i o n e x t e n d e d t o u s b y t h e B a n f f N a t i o n a l P a r k W a r d e n S e r v i c e . I w i s h t o t h a n k t h e S u p e r i n t e n d e n t M r . G . H . L . D e m p s t e r , a n d C h i e f W a r d e n M r . R . T . H a n d . I a m g r a t e f u l f o r t h e a s s i s t a n c e o f t h e B r i t i s h C o l u m b i a G a m e B r a n c h , a n d t h e f i n a n c i a l s u p p o r t r e c e i v e d f r o m t h e C a n a d i a n I n d u s t r i a l L t d . a n d t h e N a t i o n a l R e s e a r c h C o u n c i l . M a n y s t i m u l a t i n g d i s c u s s i o n s a b o u t m y w o r k w e r e v i h e l d w i t h D r . F r i t z W a l t h e r a n d D r . J . F . E i s e r i b e r g . T h i s t h e s i s w a s r e a d a n d c r i t i c i z e d b y D r s . W . S . H o a r , H . D . F i s h e r , D . J . R a n d a l l a n d D . H . C h i t t y . A b o v e a l l , I a m g r a t e f u l t o t w o p e r s o n s , D r . I a n M c T a g g a r t - C o w a n , m y s u p e r v i s o r w h o g r e a t l y e n c o u r a g e d a n d s u p p o r t e d t h i s w o r k , a n d m y w i f e , M r s . R e n a t e G e i s t , w h o s h a r e d t h e j o y s a n d s o r r o w s t h i s w o r k p r o d u c e d . S v i i T A B L E S O F C O N T E N T S P A G E I N T R O D U C T I O N 1 D E S C R I P T I O N O F T H E S P E C I E S S T U D I E D 5 M E T H O D S 1 0 C l a s s i f i c a t i o n o f s h e e p i n t o s e x - a g e c l a s s e s 1 0 M e t h o d s o f c o l l e c t i n g d a t a 1 5 P A R T I . D E S C R I P T I O N S O F S H E E P B E H A V I O U R P A T T E R N S 2 2 I n t r o d u c t i o n 2 2 H a b i t a t b e h a v i o u r 2 5 B o d y c a r e b e h a v i o u r 2 8 S o c i a l b e h a v i o u r , 3 4 A l a r m , a t t e n t i o n , h o r n i n g a n d e l i m i n a t i o n b e h a v i o u r 3 4 O r i e n t a t i o n s t o w a r d s c o n s p e c i f i c s 3 7 B e h a v i o u r p a t t e r n s e x c h a n g e d b e t w e e n c o n s p e c i f i c s 3 8 H o r n d i s p l a y s 3 9 T w i s t 4 1 F r o n t k i c k 4 2 N e c k f i g h t 4 4 M o u n t 4 4 E j a c u l a t i o n 4 5 C o u r t s h i p 4 5 H o r n t h r e a t 4 7 H o r n i n g , r u b b i n g , n u z z l i n g . . . . 4 7 B u t t 4 8 C l a s h 4 9 P r i m a r y e f f e c t s o f c l a s h i n g . . . 5 1 A S e c o n d a r y e f f e c t o f c l a s h i n g . . 5 3 D e f e n s e m e c h a n i s m s 5 4 T h r e a t j u m p 5 7 H e a d s h a k e 5 8 Q u a l i t a t i v e d i f f e r e n c e s i n t h e b e h a v i o u r o f S t o n e ' s , D a l l ' s a n d b i g h o r n s h e e p 5 8 v i i i P A G E P A R T I I . A N A N A L Y S I S O F T H E R U L E S ' O F S O C I A L B E H A V I O U R 6 0 I n t r o d u c t i o n • • • 6 0 R e s u l t s a n d d i s c u s s i o n 6 4 S o c i a l p r e f e r e n c e 6 4 I n t e r a c t i o n i n i t i a t i o n 6 9 B e h a v i o u r p a t t e r n s e q u e n c e 7 0 T h e " n o r m a l " i n t e r a c t i o n s 7 3 T h e h u d d l e 7 5 B e h a v i o u r o f t h e d o m i n a n t C l a s s I V 7 7 r a m g u a r d i n g a n e s t r o u s e w e 7 7 B e h a v i o u r o f s u b o r d i n a t e r a m s a b o u t e s t r o u s e w e s 7 7 D o m i n a n c e f i g h t s 7 8 I n t e r a c t i o n s b e t w e e n r a m s a n d e w e s . . . . 7 9 P A R T I I I . D E S C R I P T I O N O F . S H E E P B E H A V I O U R D U R I N G E A R L Y W I N T E R 8 5 N o r m a l d a i l y b e h a v i o u r 8 5 G r o u p i n t e r a c t i o n s 8 6 D o m i n a n c e f i g h t s 9 0 U n r i t u a l i z e d f i g h t s 9 8 Y e a r l i n g r a m s g a i n d o m i n a n c e o v e r e w e s 9 9 T h e p r e - r u t 1 ° 1 E s t r u s i n e w e s 1 ° 4 C o u r t s h i p b y t h e e w e H 5 P o s t - r u t 1 1 8 P A R T I V . O N T H E E V O L U T I O N O F M O U N T A I N S H E E P 1 2 0 I n t r o d u c t i o n 1 2 0 T h e p r i m i t i v e c a p r i d s 1 2 1 C h a n g e s i n t h e e x t e r n a l a p p e a r a n c e o f c a p r i d s 1 2 4 C h a n g e s i n t h e b e h a v i o u r o f c a p r i d s 1 3 6 N e o t e n y a s a f a c t o r i n s h e e p b i o l o g y 1 4 2 A n e x p l a n a t i o n o f t h e m a j o r s e l e c t i o n f o r c e s i n s h e e p e v o l u t i o n 1 5 0 I n r e t r o s p e c t 1 5 5 C O N C L U S I O N S 1 6 X L I T E R A T U R E C I T E D 1 6 6 1 71 F I G U R E S J - ' - L T A B L E S 2 5 0 i x L I S T O F F I G U R E S F I G U R E P A G E 1 . A 1 4 y e a r o l d S t o n e ' s r a m . 1 7 1 2 . A n e i g h t y e a r o l d B a l l ' s r a m . 1 7 2 3 . A n o l d b i g h o r n r a m . 1 7 2 4 . A s k e t c h i l l u s t r a t i n g v a r i a t i o n s i n t h e c o a t p a t t e r n s a n d h o r n f o r m s o f S t o n e ' s s h e e p . 1 7 3 5 . A s i x m o n t h s o l d b i g h o r n l a m b . 1 7 4 6 . A s i x m o n t h s o l d D a l l ' s l a m b . 1 7 4 7 . S e x - a g e c l a s s e s o f b i g h o r n s h e e p 1 7 5 a . b . c . d . e . f . g . h . L a m b Y e a r l i n g e w e A d u l t e w e Y e a r l i n g r a m C l a s s I r a m C l a s s I I r a m C l a s s I I I r a m C l a s s I V r a m 8 . A c o m p a r i s o n o f b i g h o r n e w e s w i t h y e a r l i n g r a m s . 1 7 6 9 . A w e l l d e v e l o p e d y e a r l i n g D a l l ' s r a m . 1 7 6 1 0 . A C l a s s I r a m i n e w e c o m p a n y — a c o m p a r i s o n . 1 7 7 1 1 . A m a l e m u l e d e e r i n a r e s t i n g p o s i t i o n n o t o b s e r v e d i n s h e e p . 1 7 8 1 2 . A C l a s s I I I b i g h o r n r a m i n t h e n o r m a l r e s t i n g p o s t u r e . 1 7 8 1 3 . A g r o u p o f r e s t i n g D a l l ' s s h e e p . 1 7 9 1 4 . S k e t c h o f a b i g h o r n e w e a n d l a m b a t r e s t . 1 8 0 1 5 . A b u l l m o o s e r e s t i n g i n d e e p , f l u f f y s n o w . 1 8 1 1 6 . A n o l d D a l l ' s e w e c l e a n i n g a b e d b e f o r e l y i n g d o w n . 1 8 2 1 7 . A r a m d i s l o d g i n g a e w e f r o m h e r b e d . 1 8 3 X F I G U R E P A G E 1 8 . A y e a r l i n g r a m p a w i n g a f e e d i n g c r a t e r t h r o u g h t h e s n o w . 1 8 3 1 9 . A b i g h o r n e w e i n l a t e s t a g e s o f t h e m o u l t . 1 8 4 2 0 . A C l a s s I r a m s c r a t c h i n g h i s w i t h e r s w i t h a h o r n t i p * 1 8 5 2 1 . T h e r e s u l t s o f e x t e n s i v e h o r n s c r a t c h i n g . 1 8 5 2 2 . S k e t c h o f a C l a s s I I S t o n e ' s r a m s t r e t c h i n g i t s e l f . 1 8 6 2 3 . U r i n a t i o n p o s t u r e o f a e w e . 1 8 7 2 4 . T h e p o s t u r e o f t h e u n d i s t r i b e d , w a l k i n g s h e e p . 1 8 8 2 5 . T h e a l a r m p o s t u r e o f s h e e p . 1 8 8 2 6 . T h e a l a r m p o s t u r e o f e l k . 1 8 9 2 7 . A l e r t p o s t u r e s o f s h e e p . 1 8 9 2 8 . A f u l l c u r l h o r n i n g t h e b r a n c h e s o f a p i n e . 1 9 0 2 9 . A s m a l l l o d g e p o l e p i n e a t t i m b e r l i n e s h o w i n g t h e e f f e c t s o f h o r n i n g . 1 9 0 3 0 . A s u b o r d i n a t e e w e l o o k i n g a w a y f r o m d o m i n a n t d u r i n g e n c o u n t e r . 1 9 1 3 1 . A c o m p a r i s o n o f o r i e n t a t i o n s i n a g r o u p o f l a m b s i n t h e p r e s e n c e a n d a b s e n c e o f a l a r g e r s h e e p . 1 9 2 3 2 . A s o c i a l i n t e r a c t i o n o n a b e d d i n g s i t e b e t w e e n D a l l ' s s h e e p , a n d t h e r e s u l t i n g o r i e n t a t i o n s o f t h e g r o u p a t r e s t . 1 9 3 3 3 . T h e l o w - s t r e t c h a n d h o r n t h r e a t s h o w n b y a C l a s s I V a n d I I r a m r e s p e c t i v e l y . 1 9 4 3 4 . T h e p r e s e n t . 1 9 4 3 5 . H e a d a n d b o d y o r i e n t a t i o n s o f r a m s d u r i n g a h o r n d i s p l a y . 1 9 5 3 6 . A h o r n d i s p l a y s h o w n b y a d o m i n a n t t o w a r d s a s u b o r d i n a t e . 1 9 6 X I F I G U R E P A G E 3 7 . M u t u a l h o r n d i s p l a y i n g b y r a m s o f e q u a l h o r n s i z e . 1 9 6 3 8 . A c r o u c h e d l o w - s t r e t c h s h o w n b y r a m s o c c a s i o n a l l y t o f e m a l e s . 1 9 7 3 9 . A l o w - s t r e t c h i n g B a l l ' s r a m . 1 9 7 4 0 . T h e t w i s t a n d t o n g u e f l i c k e r s h o w n b y a c o u r t i n g B a l l ' s r a m . 1 9 8 4 1 . T h e f r o n t - k i c k , c o m b i n e d w i t h a t w i s t . 1 9 9 4 2 . T h e f r o n t - k i c k , m a y l a n d a n y w h e r e o n t h e o p p o n e n t s v e n t r a l p a r t ; h e r e o n t h e c h i n . 1 9 9 4 3 . T h e v e s t e g e s o f t h e n e c k f i g h t . 2 0 0 4 4 . T h e m o u n t b y a d o m i n a n t r a m o n a s u b o r d i n a t e . L a t t e r s h o w s l o r d o s i s . 2 0 0 4 5 . A u t e r o t i c e j a c u l a t i o n . 2 0 1 4 6 . T w o r a m s s i m u l t a n e o u s l y c o u r t i n g a e w e . 2 0 2 4 7 . U r i n a t i n g e w e w i t h r a m e x a m i n i n g h e r v u l v a . 2 0 2 4 8 . L i p c u r l i n g r a m s . 2 0 3 4 9 . S m a l l r a m t w i s t i n g t o e w e w i t h o u t i n t e r f e r e n c e b y l a r g e r r a m s . 2 0 3 5 0 . R u b b i n g ( a ) a n d h o r n i n g ( b ) p e r f o r m e d b y a s m a l l r a m o n a l a r g e r o n e . 2 0 4 5 1 . A C l a s s I V r a m b u t t s a C l a s s I I I r a m . 2 0 5 5 2 . T h e r u s h o r h o r n c h a r g e . 2 0 5 5 3 . I n i t i a t i o n o f a c l a s h b y t w o r a m s ( a ) , a n d t w o l a m b s ( b ) . 2 0 6 5 4 . C o n t a c t d u r i n g t h e c l a s h . 2 0 7 5 5 . S k e t c h e s o f r a m s i n s u c c e s s i v e p h a s e s o f a c l a s h . 2 0 8 5 6 . B o w n w a r d p u s h w i t h h e a d d u r i n g c l a s h ; p i v o t i n g a b o u t s h o u l d e r s . 2 0 9 x i i F I G U R E P A G E 5 7 . D o w n w a r d p u s h w i t h t h e h e a d d u r i n g c l a s h ; p i v o t i n g a b o u t a c e t u b u l u m . 2 0 9 5 8 . A c l a s h t h a t m i s s e d . 2 1 0 5 9 . C l a s h i n w h i c h f r o n t l e g s a r e o f f t h e g r o u n d . 2 1 1 6 0 . C l a s h i n w h i c h t h e h o r n s o f t h e o p p o n e n t s s l i p p e d o f f e a c h o t h e r . 2 1 1 6 1 . T h e e f f e c t o f t h e c l a s h o n a s m a l l r a m ( a ) o n a b i g r a m ( b ) . 2 1 2 6 2 . T h e e f f e c t s o f t h e c l a s h o n t h e h o r n s a n d f a c e o f a r a m . 2 1 3 6 3 . O l d r a m w i t h o n e h o r n b r o k e n o f f . 2 1 3 6 4 . A e w e c a t c h e s t h e b l o w o f a C l a s s I r a m . 2 1 4 6 5 . S k i n t h i c k n e s s m e a s u r e m e n t s ( i n m m ) o f m a l e f e r a l g o a t , S t o n e ' s s h e e p a n d m o u n t a i n g o a t . 2 1 5 6 6 . T h r e a t j u m p b y a p l a y i n g r a m . 2 1 6 6 7 . D i s t r i b u t i o n s o f s o c i a l i n t e r a c t i o n s b y S t o n e ' s s h e e p o f a l l c l a s s e s o n a l l c l a s s e s . 2 1 7 6 8 . I n t e r a c t i o n p r e f e r e n c e s o f r a m s o n o t h e r s h e e p . 2 1 8 6 9 . P e r c e n t f r e q u e n c y o f l o w - s t r e t c h a p p r o a c h e s b y r a m s t o w a r d s s m a l l e r a n d l a r g e r r a m s . 2 1 9 7 0 . R a n k o r d e r s o f f r e q u e n c i e s w i t h w h i c h b e h a v i o u r p a t t e r n s f o l l o w e d t h e f i r s t , i n i t i a t i n g p a t t e r n . 2 2 0 7 1 . F r e q u e n c i e s w i t h w h i c h b e h a v i o u r p a t t e r n s o c c u r w i t h i n i n t e r a c t i o n s . 2 2 1 7 2 . A c o m p a r i s o n o f p a t t e r n f r e q u e n c i e s i n r a m i n t e r a c t i o n s f r o m s e v e r a l s o c i a l s i t u a t i o n s . 2 2 2 7 3 . B e h a v i o u r p a t t e r n f r e q u e n c i e s i n a d o m i n a n c e f i g h t o f r a m s . 2 2 3 7 4 . P a t t e r n f r e q u e n c i e s i n i n t e r a c t i o n s o f r a m s w i t h n o n - e s t r o u s e w e s . 2 2 4 x i i i F I G U R E P A G E 7 5 . A c o m p a r i s o n o f p a t t e r n f r e q u e n c i e s f r o m t h e i n t e r a c t i o n s o f b r e e d i n g r a m s w i t h e s t r o u s e w e s , a n d s u b o r d i n a t e r a m s w i t h e a c h o t h e r i n t h e p r e s e n c e o f e s t r o u s e w e s . 2 2 5 7 6 . F r e q u e n c y o f s e x u a l p a t t e r n s b y C l a s s I V - I I r a m s o n a l l s h e e p c l a s s e s . A , s n i f f i n g r e a r . B , m o u n t i n g . 2 2 6 7 7 . W i t h d r a w a l f r e q u e n c i e s f r o m m o u n t i n g a n d f r o n t - k i c k . 2 2 7 7 8 . R a m b a n d d u r i n g f e e d i n g w i t h w e l l s p a c e d i n d i v i d u a l s . 2 2 8 7 9 . A g r o u p o f r a m s e n t e r i n g a n o t h e r b a n d . 2 2 8 8 0 . B i g h o r n r a m s i n a h u d d l e . 2 2 9 8 1 . Y o u n g r a m s a t p l a y i n s p r i n g . 2 3 0 8 2 . R a m s d u r i n g e x u b e r a n t p l a y . 2 3 0 8 3 . B e h a v i o u r p h a s e s o f r a m s i n a d o m i n a n c e f i g h t . 2 3 1 8 4 . A v i c i o u s f i g h t b e t w e e n r a m s . 2 3 2 8 5 . T w o r a m s p u s h i n g e a c h o t h e r i n a v i c i o u s f i g h t . 2 3 2 8 6 . T w o r a m s a c c i d e n t a l l y l o c k e d h o r n s . 2 3 3 8 7 . Y e a r l i n g r a m m o u n t i n g y e a r l i n g e w e . 2 3 4 8 8 . : Y e a r l i n g r a m l o w - s t r e t c h i n g t o y e a r l i n g e w e . 2 3 4 8 9 . : V i c i o u s f i g h t b e t w e e n y e a r l i n g r a m a n d e w e . 2 3 5 9 0 . R a m s c h a s i n g a n e s t r o u s e w e . 2 3 6 9 1 . D e f e n d i n g r a m a b o u t t o d i s l o d g e a m o u n t i n g s u b o r d i n a t e f r o m t h e e s t r o u s e w e . 2 3 6 9 2 . T h e d o m i n a n t r a m i n p o s i t i o n b e t w e e n e w e a n d s u b o r d i n a t e r a m s . 2 3 7 9 3 . D o m i n a n t c h a s i n g o f f a C l a s s I r a m . 2 3 7 9 4 . C o u r t s h i p b e h a v i o u r o f t h e e s t r o u s e w e . 2 3 8 XXV F I G U R E P A G E 9 5 . P e r c e n t ' f r e q u e n c y w i t h w h i c h S t o n e ' s r a m s w e r e o b s e r v e d a s s i n g l e s d u r i n g t h e y e a r . 2 3 9 9 6 . P e r c e n t f r e q u e n c y w i t h w h i c h S t o n e ' s r a m s o f v a r i o u s a g e s w e r e o b s e r v e d a s s i n g l e s . 2 3 9 9 7 . A m m o t r a g u s c o m p a r e d w i t h t h r e e s p e c i e s o f C a p r a . ' 2 4 0 9 8 . A m m o t r a g u s c o n n e c t e d w i t h t h e O v i s a m n i o n c l i n e . 2 4 1 9 9 . G e o g r a p h i c l o c a t i o n s o f A m m o t r a g u s a n d t h e a m n i o n . , c l i n e a s w e l l a s o t h e r s p e c i e s a n d r a c e s o f s h e e p . 2 4 2 1 0 0 . A c o m p a r i s o n o f a n a d v a n c e d m e m b e r o f t h e a m n i o n c l i n e ( p o l i ) w i t h a m o r e p r i m i t i v e o n e ( o r i e n t a l i s ) . 2 4 3 1 0 1 . A c o m p a r i s o n o f e q u a l a g e d m a l e s f r o m f i v e r a c e s o f " A m e r i c a n " s h e e p . 2 4 4 1 0 2 . A g e d e p e n d e n t c h a n g e s i n t h e f r e q u e n c y o f b u t t i n g a n d m o u n t i n g o f r a m s . 2 4 5 1 0 3 . A g e d e p e n d e n t c h a n g e s i n t h e m a n n e r o f a p p r o a c h a n d f r e q u e n c i e s o f d i s p l a y s e x c h a n g e d b e t w e e n r a m s o f s i m i l a r d o m i n a n c e r a n k . 2 4 6 1 0 4 . A g e d e p e n d e n t c h a n g e s i n t h e f r e q u e n c i e s o f e x c h a n g e o f f r o n t - k i c k s a n d t w i s t s b e t w e e n r a m s o f s i m i l a r d o m i n a n c e r a n k . 2 4 7 1 0 5 . A n n u a l h o r n s e g m e n t g r o w t h o f a D a l l i s a n d b i g h o r n r a m . 2 4 8 1 0 6 . I n t e n s i t i e s o f i n t e r a c t i o n o f r a m s o f e q u a l h o r n s i z e a s r e v e a l e d b y f r e q u e n c i e s o f f r o n t - k i c k s . 2 4 9 XV L I S T O F T A B L E S T A B L E P A G E I . W e i g h t s a n d m e a s u r e m e n t s o f t w o S t o n e ' s s h e e p . 2 5 0 I I . F r e q u e n c y w i t h w h i c h s h e e p o f v a r i o u s c l a s s e s w e r e s e e n w i t h o u t c o m p a n y . 2 5 0 I I I . L e a d e r s h i p i n b i g h o r n r a m s . 2 5 1 I V . F r e q u e n c i e s o f a g g r e s s i v e p a t t e r n s i n t h e i n t e r a c t i o n s o f a d u l t S t o n e ' s a n d b i g h o r n r a m s . 2 5 1 1 I N T R O D U C T I O N T h e l i f e o f a l a r g e , s o c i a l m a m m a l i s i n t r i n s i c a l l y - i n t e r e s t i n g s i n c e a k n o w l e d g e o f t h e r u l e s i t l i v e s b y s t i m u l a t e s c o m p a r i s o n s a n d u l t i m a t e l y c o n t r i b u t e s t o m a n ' s k n o w l e d g e a b o u t h i m s e l f . T o l i v e s o c i a l l y m e a n s t o l i v e b y r u l e s , w h e t h e r o r n o t t h e s e r u l e s a r e l a r g e l y c o n c e p t u a l t h o u g h n o t a r b i t r a r y - a s w o u l d a p p e a r t r u e f o r m a n - o r a r e l a r g e l y f i x e d i n t h e s t i l l m y s t e r i o u s c e n t r a l n e r v o u s s y s t e m a n d a c t e d o u t i n i n t e l l e c t u a l b l i n d n e s s . O u r o u t l o o k o n l i v i n g s o c i a l l y i s l i n k e d w i t h t h e n o t i o n o f p r o g r e s s . T h i s n o t i o n a p p e a r s t o b e a n u n s p o k e n t h e m e i n A l l e e ' s c o n  c e p t o f a n i m a l c o o p e r a t i o n ( A l l e e , 1 9 5 1 ) . I t m a y w e l l h a v e a r i s e n f r o m t h e " r o m a n t i c f a l l a c y " , a s A r d r e y ( 1 9 6 3 ) s o a p t l y n a m e s i t , w h i c h r e g a r d s m a n a s t h e e p i t o m e o f p r o g r e s s , a n o t i o n w h i c h o u r s o c i a l i n s t i t u t i o n s c o n t i n u o u s l y p r o j e c t a n d r e i n f o r c e . S t a t e d b l u n t l y , s i n c e m a n i s s o c i a l , l i v i n g s o c i a l l y i s p r o g r e s s i v e , l i v i n g o t h e r w i s e i s n o t i S o m e w i l l r e c o i l f r o m t h i s s t a t e m e n t , y e t h o w m a n y o f t h e s e w o u l d u n  h e s i t a t i n g l y t i c k o f f t h e a d v a n t a g e s o f l i v i n g s o c i a l l y v e r s u s s o l i t a r i l y ? Y e t , h e r e i s t h e c r u x o f t h e m a t t e r . I f t h e a n i m a l s ' w a y o f l i f e a r e a d a p t a t i o n s , s o l u t i o n s t o l a r g e r a n d m i n o r p r o b l e m s p o s e d b y a n e n v i r o n m e n t , t h e n l i v i n g s o c i a l l y o r s o l i t a r i l y a r e a d a p t a t i o n s a n d c a n n o t b e i n h e r e n t l y p r o  g r e s s i v e . T h e r e c a n n o t b e a d v a n t a g e s i n l i v i n g s o c i a l l y 2 o v e r l i v i n g s o l i t a r i l y , n o t i f b o t h a r e p r o d u c t s o f e v o  l u t i o n . C l e a r l y , t h e q u e s t i o n o f w h a t a d v a n t a g e s s o c i a l s p e c i e s A h a s o v e r s o l i t a r y s p e c i e s B i s u n a n s w e r a b l e i n p r i n c i p l e . T h e f a c t s r e m a i n t h a t a v a r i e t y o f m a m m a l i a n s o c i e t i e s d o e x i s t , t h a t t h e y d o h a v e o r d e r a n d r u l e s o f b e h a v i o u r ( s e e E i s e n b e r g , 1 9 6 6 ) , a n d t h a t w e s t i l l k n o w l i t t l e a b o u t w h y , h o w a n d w h e n t h e y a r o s e . I h o p e t o a n s w e r t h i s i n p a r t f o r o n e g r o u p o f c l o s e l y r e l a t e d r u m i  n a n t s , t h e s h e e p . T h e a p p r o a c h h a s b e e n n o t t o s e a r c h f o r a d v a n t a g e s o f s o c i a l l i v i n g , b u t t o e x p l o r e t h e e v o l u t i o n o f s o c i a l b e h a v i o u r a n d e x t e r n a l a p p e a r a n c e o f A m e r i c a n m o u n t a i n s h e e p . W h a t s e l e c t i v e f o r c e s a r e r e s p o n s i b l e f o r t h e c h a r a c t e r i s t i c s , s t r u c t u r e s a n d a c t i o n s o f t h e s e a n i m a l s ? A s t u d y o f t h i s n a t u r e d o e s n o t d e a l w i t h o n e , b u t w i t h m a n y p r o b l e m s a n d i s h e l d t o g e t h e r o n l y b y o n e c o m m o n t h e m e . T h e f i n d i n g s c a n b e r e a d i n t h e A b s t r a c t a n d C o n c l u s i o n s . S i n c e , i n t h i s t h e s i s , b e h a v i o u r w a s u s e d a s a k e y t o t h e u n d e r s t a n d i n g o f a n a n i m a l ' s e v o l u t i o n , i t w a s m y f i r s t c o n c e r n t o p r o d u c e a d e t a i l e d d o c u m e n t a t i o n o f m o u n t a i n s h e e p b e h a v i o u r a n d i t s v a r i a b l e s . T h i s a p p e a r s t o b e e s s e n t i a l b e f o r e v a l i d i n f e r e n c e s c a n b e m a d e a b o u t t h e f u n c t i o n o f s h e e p a d a p t a t i o n s a n d t h e s e l e c t i v e f o r c e s s h a p i n g t h e s e . S e c o n d l y , a d e t a i l e d d o c u m e n t a t i o n i s e s s e n t i a l t o a l l o w t h e r e a d e r t o c h e c k t h e r e p o r t e d f i n d i n g s 3 h i m s e l f . U n l i k e t h e r e s u l t s o f a l a b o r a t o r y s t u d y , t h e f i n d i n g s o f a f i e l d s t u d y c a n o n l y r a r e l y b e r e a d i l y c h e c k e d , h e n c e t h e d a t a m u s t b e e x a c t , d e t a i l e d , o r g a n i z e d s o t h a t t h e r e a d e r c a n s e e h o w e a c h c o n c l u s i o n w a s f o r m e d , a n d v o l u m i n o u s e n o u g h t o a l l o w h i m s o m e e x p l o r a t i o n o f h i s o w n . T h e s e t h o u g h t s a r e r e f l e c t e d i n t h e o r g a n i z a t i o n o f t h e t h e s i s . T h e f i r s t t h r e e p a r t s d e a l m a i n l y w i t h a d e s  c r i p t i o n a n d a n a l y s i s o f s o c i a l b e h a v i o u r , w h i l e t h e f o u r t h p a r t d e a l s w i t h i n t e r p r e t a t i o n o f i t i n t h e l i g h t o f s h e e p m o r p h o l o g y a n d z o o g e o g r a p h y . H o w e v e r , t h e d i v i s i o n i s n o t s o c l e a r c u t . A l t h o u g h t h e f i r s t p a r t d e a l s m a i n l y w i t h d e s c r i p t i o n s o f b e h a v i o u r p a t t e r n s , I h a v e a d d e d e s s e n t i a l i n f o r m a t i o n t o e a c h d e s c r i p t i o n a n d i n t e r p r e t e d t h e s e , t o m a k e e a c h b e h a v i o u r p a t t e r n a s c o m p l e t e l y c o m p r e h e n s i b l e a s p o s s i b l e . F u r t h e r m o r e , t w o e s s a y s o n t h e h a b i t a t a n d b o d y c a r e b e h a v i o u r a r e a d d e d t o c l a r i f y t h e i r p o s i t i o n i n t h e e v o l u t i o n o f s h e e p . I n t h e s e c o n d p a r t , t h e r u l e s w h i c h s h e e p f o l l o w w h e n i n t e r a c t i n g w i t h o n e a n o t h e r a r e t r a c e d o u t . H e r e t h e b e h a v i o u r p a t t e r n s h a v e b e e n a n a l y s e d q u a n t i t a t i v e l y , a n d i t i s s h o w n w h i c h s h e e p i n t e r a c t s , h o w i t t r e a t s t h e c h o s e n c o m  p a n i o n a n d h o w i t i s t r e a t e d i n r e t u r n , a n d h o w s u c h i n t e r  a c t i o n s v a r y . T h e t h i r d p a r t o f t h e t h e s i s i s a g a i n 4 d e s c r i p t i v e . T h e s o c i a l b e h a v i o u r p a t t e r n s d e s c r i b e d a n d a n a l y s e d p r e v i o u s l y a r e s h o w n i n t h e i r n a t u r a l c o n t e x t . T h e b e h a v i o u r o f s h e e p d u r i n g f a l l a n d e a r l y w i n t e r i s d e s c r i b e d w i t h a s p e c i a l e m p h a s i s o n r a m s . T h e f i r s t t h r e e p a r t s f a m i l i a r i z e t h e r e a d e r w i t h t h o s e c h a r a c t e r i s t i c s o f s h e e p w h i c h a r e i m p o r t a n t t o t h e f o u r t h p a r t . I n t h e f o u r t h p a r t o f t h e t h e s i s I h a v e a t t e m p t e d t o a n s w e r h o w s h e e p e v o l v e d , w h y t h e y e v o l v e d a n d , t o s o m e e x t e n t , w h e n t h e y e v o l v e d . T h e r e a r e n o c o m p l e t e a n s w e r s h e r e ; s u c h a n s w e r s a r e p r o b a b l y i m p o s s i b l e t o g i v e . T h e c o n c e p t s p r o p o s e d m a y b e v a l i d f o r n o r t h e r n r u m i n a n t s o t h e r t h a n s h e e p . A n d w h a t a b o u t s o c i a l i t y ? I t a p p e a r s a s a b y - p r o d u c t o f t h e s h e e p ' s e v o l u t i o n , w h i c h i s n o t d i r e c t l y b u t i n d i r e c t l y s e l e c t e d . 5 D E S C R I P T I O N S O P T H E S P E C I E S S T U D I E D S t o n e ' s s h e e p ( O v i s flaili s t o n e i A l l e n 1 8 9 7 ) ( P i g . 1 ) : S t o n e ' s s h e e p a r e d a r k c o l o u r e d D a l l ' s s h e e p w h i c h c h a r a c t e r i s t i c a l l y h a v e l a r g e v a r i a t i o n s i n c o l o u r a n d s h a d e p a t t e r n s . T h e y m a y b e b l a c k , a s h - g r e y , s i l v e r , b r o w n , y e l l o w i s h o r a l m o s t w h i t e i n c o l o u r . I n t h e b l a c k s h e e p t h e r e i s a b r o w n i s h t i n g e i n t h e h a i r . I n d i v i d u a l s o f v a r i o u s c o l o u r s m a y b e f o u n d i n o n e b a n d ; o n m y s t u d y a r e a t h e b l a c k a n d d a r k g r e y f o r m s p r e d o m i n a t e d . T h e i n d i v i d u a l s a r e n o t u n i f o r m l y c o l o u r e d . T h e h e a d , t h e n a p e o r e v e n t h e w h o l e n e c k i s l i g h t e r t h a n t h e b o d y . T h e w h i t e b e l l y , r u m p p a t c h a n d l e g m a r k i n g s d i f f e r s o m e w h a t f r o m t h o s e o f b i g h o r n s h e e p ( p . 1 2 7 a n d F i g . 1 0 1 ) ; t h e l a t t e r l a c k t h e b e l l y - b a n d w h i c h i s o f t e n s e e n i n S t o n e ' s r a m s ( F i g . 4 ) , w h i l e o l d r a m s u s u a l l y l a c k t h e c l e a r l y d e  f i n e d , w h i t e b e l l y o f S t o n e ' s r a m s . T h e t a i l i s l a r g e r t h a n i n b i g h o r n s a n d i s v i r t u a l l y a l w a y s c o n t i n u o u s v ^ i t h t h e d a r k d o r s a l s t r e a k . T h e h o r n s a r e d a r k a m b e r o r b r o w n i n c o l o u r a n d v a r y i n s h a p e , s i z e a n d s p r e a d b e t w e e n i n d i v i d u a l s . O n m y s t u d y a r e a t h e r a m s u s u a l l y h a d c l o s e c u r l e d h o r n s ; b r o o m e d h o r n - t i p s , c h a r a c t e r i s t i c o f b i g h o r n s h e e p , w e r e n o t u n c o m m o n . 6 O n t h e s t u d y a r e a , l a r g e r a m s i n e a r l y f a l l w o u l d p r o b a b l y h a v e a w e i g h t o f b e t w e e n 1 8 0 a n d 2 2 0 l b s . I n T a b l e I s o m e v i t a l s t a t i s t i c s a r e g i v e n f o r a r a m a n d a e w e . T h e r a m w a s s h o t d u r i n g t h e r u t a n d a p p e a r e d e m a c i a t e d . H e h a d l i t t l e f a t a n d a s m a l l r u m e n f i l l , h e n c e t h e l o w w e i g h t . T h e e w e , a n u n u s u a l l y l a r g e a n d o l d i n d i v i d u a l , w a s a l s o s h o t i n e a r l y D e c e m b e r . A, 2 ^ y e a r o l d r a m , c o l l e c t e d w i t h t h e e w e , h a d a l i v e w e i g h t o f 1 1 7 l b s . T h e p e r c e n t w e i g h t o f t h e d r e s s e d o u t c a r c a s s w a s 5 5 f o r t h e r a m , 5 0 f o r t h e e w e a n d 5 0 f o r t h e 2 ^ y e a r o l d r a m . T h e s e s h e e p w e r e c u t i n t o p i e c e s a n d w e i g h e d w i t h a p o c k e t s p r i n g s c a l e ( 5 0 l b s . ) s h o r t l y a f t e r t h e i r d e a t h . L i v e w e i g h t w a s c a l c u l a t e d b y m u l t i p l y i n g c a r c a s s w e i g h t p l u s v i c e r a b y 1 . 0 8 t o c o m p e n s a t e f o r b l o o d l o s s . ( T h e f a c t o r 1 . 0 8 i s b a s e d o n 7 0 m l . o f b l o o d p e r k g . o f b o d y w e i g h t a s i s f o u n d i n d o m e s t i c g o a t . ) T h e S t o n e ' s s h e e p s t u d y a r e a l i e s i n n o r t h e r n B r i t i s h C o l u m b i a , o n t h e s o u t h e r n f r i n g e o f t h e E a g l e N e s t R a n g e , n o r t h o f t h e S p a t z i s i r i v e r . I s t a y e d o n t h e s t u d y a r e a f r o m J u n e 1 9 , 1 9 6 1 t o J a n u a r y 2 7 , 1 9 6 3 , a n d a g a i n f r o m N o v e m b e r 2 6 t o D e c e m b e r 1 1 , 1 9 6 5 . E v e n a p a s s i n g a c q u a i n t a n c e w i t h s h e e p i n n o r t h e r n B r i t i s h C o l u m b i a m a k e s i t a p p a r e n t t h a t S t o n e ' s s h e e p n o w l i v e i n w i d e l y d i s p e r s e d , i s o l a t e d r e l i c p o p u l a t i o n s , w h i c h 7 a p p e a r t o d i f f e r f r o m o n e a n o t h e r . T h e S t o n e ' s s h e e p I s t u d i e d l i v e d t h i n l y d i s p e r s e d a t t h e e d g e o f o n e o f t h e l a r g e r r e l i c p o p u l a t i o n s . O n t h e s t u d y a r e a s h e e p a p p e a r e d t o b e h e a d i n g s l o w l y t o w a r d s e x t i n c t i o n . S h e e p a r e g r a z e r s w h i c h d e p e n d a g r e a t d e a l i n w i n t e r o n g r a s s e s g r o w i n g o n e x p o s e d s l o p e s o r i n r o c k t e r r a i n . I n t h e S t o n e ' s s h e e p s t u d y a r e a , g o o d h a b i t a t w a s l o c a l i z e d a n d n o t a b u n d a n t . T h e m o u n t a i n s w e r e l a r g e l y o v e r g r o w n b y d w a r f b i r c h s c r u b ( B e t u l a g l a n d u l o s a ) a n d t i m b e r w h i c h l e f t p r e c i o u s l i t t l e l i v i n g s p a c e f o r t h e s h e e p . T h i s w a s a w e t c o u n t r y w i t h l a r g e s n o w f a l l s . S h e e p a p p e a r e d t o s u r v i v e t h e d e e p s n o w s b y t h e a c c i d e n t o f f r e q u e n t w a r m , h u m i d w i n t e r s t o r m s w h i c h s w e p t i n f r o m t h e P a c i f i c a n d r e m o v e d t h e s n o w f r o m a f e w , s m a l l a r e a s . T h i s i s w h e r e s h e e p s p e n d m u c h o f t h e w i n t e r . T h e r e w e r e f e w s h e e p o n t h e s t u d y a r e a . T h e b a n d s w e r e q u i t e s m a l l b u t t h e i n d i v i d u a l s a p p e a r e d t o b e l a r g e a n d w e r e l i v e l y a n d r e p r o d u c t i o n w a s h i g h . I o b s e r v e d v i g o r o u s d o m i n a n c e f i g h t s i n t h i s p o p u l a t i o n o n l y , a l t h o u g h I w a t c h e d m a n y m o r e b i g h o r n a n d D a l l ' s s h e e p . T h e s m a l l n u m b e r o f s h e e p o n t h i s s t u d y a r e a w a s a n a d v a n t a g e s i n c e i t a l l o w e d m e t o g e t t o k n o w t h e i n d i v i d u a l s b e t t e r . T h e s e 8 s h e e p c o n t r i b u t e d m o r e t o t h e s t u d y t h a n t h e o t h e r p o p u  l a t i o n s . D a l l ' s s h e e p ( O v i s d a l l i d a l l i N e l s o n 1 8 8 4 ) ( F i g . 2 ) : D a l l ' s s h e e p a r e p u r e w h i t e , a l t h o u g h s o m e i n d i  v i d u a l s w i t h d a r k h a i r s o n t h e t a i l d o o c c u r . T h e y a r e s i m i l a r i n s i z e t o S t o n e ' s s h e e p . A 5 ^ y e a r o l d r a m s h o t c l o s e t o m y s t u d y a r e a i n O c t o b e r w e i g h e d 2 2 6 l b s . , l i v e w e i g h t . T h e r a m s o n t h i s s t u d y a r e a c a r r i e d d i s t i n c t l y m o r e f l a r i n g h o r n s t h a n d i d t h e S t o n e ' s s h e e p , w h i c h c a n b e s e e n i n t h e p h o t o g r a p h s . T h e s t u d y a r e a w a s l o c a t e d o n S h e e p M o u n t a i n , M i l e 1 0 6 6 A l a s k a H i g h w a y , a t K l u a n e L a k e i n t h e Y u k o n T e r r i  t o r y . I s t a y e d w i t h t h e s h e e p f r o m S e p t e m b e r 1 5 - N o v e m b e r 2 4 , 1 9 6 5 . T h e D a l l ' s s h e e p i n t h e S t . E l l i a s r a n g e l i v e d i n a m u c h m o r e f a v o u r a b l e h a b i t a t t h a n d i d t h e S t o n e ' s s h e e p i n t h e E a g l e N e s t R a n g e . G l a c i a t i o n h a d b e e n r e l a t i v e l y r e c e n t a n d t h e g l a c i e r s w e r e s t i l l l a r g e . T h e m o u n t a i n s w e r e b a r e o f t i m b e r e x c e p t f o r a b r o k e n f r i n g e a t t h e i r b a s e s a n d n o r t h s l o p e s . T h e c l i m a t e w a s d r y ; w i n d s w e r e f r e q u e n t a n d s t r o n g . T h e m o u n t a i n s l o p e s w e r e s p a r s e l y c o v e r e d w i t h g r a s s e s a n d f o r b s , w h i l e a f e w p a t c h e s o f w i l l o w f o l l o w e d t h e c r e e k b e d s . T h e s l o p e s c a r r i e d a c o n s i d e r a b l e 9 c o v e r o f d u s t , w h i c h w a s p r o b a b l y d e p o s i t e d b y t h e f r e q u e n t d u s t s t o r m s c r e a t e d b y w i n d s d e s c e n d i n g a l o n g t h e r i v e r v a l l e y f r o m t h e g l a c i e r s . T h e r e w a s a h u g e e x p a n s e o f s h e e p h a b i t a t , t h e b e s t t h a t I h a v e s e e n t o d a t e . S h e e p w e r e t h e d o m i n a n t r u m i n a n t s h e r e ; m o u n t a i n g o a t s ( O r e a m n o s ) a n d m o o s e ( A l c e s ) w e r e r a r e a n d c a r i b o u a b s e n t f r o m t h e s t u d y a r e a . A l t h o u g h t h e s h e e p o n t h e s t u d y a r e a a p p e a r e d t o b e l a r g e , t h e y w e r e l e s s l i v e l y t h a n m y S t o n e ' s s h e e p ; t h e r a m s i n t e r a c t e d s u r p r i s i n g l y i n  f r e q u e n t l y w i t h b u t t s o r c l a s h e s . T h e r e w e r e v e r y m a n y s h e e p ; I l e a r n e d t o r e c o g n i z e d u r i n g m y s h o r t s t a y o n l y a f e w i n d i v i d u a l s . T h e s e s h e e p c o n t r i b u t e d p r i m a r i l y f i l m d o c u m e n t a t i o n a n d q u a l i t a t i v e o b s e r v a t i o n s . B i g h o r n s h e e p ( O v i s c a n a d e n s i s c a n a d e n s i s S h a w 1 8 0 4 ) ( F i g . 3 ) : B i g h o r n s a r e c o n s i d e r e d l a r g e r i n b o d y s i z e t h a n S t o n e ' s o r D a l l ' s s h e e p , a n d t h e y h a v e h e a v i e r , u s u a l l y c l o s e c u r l e d , b r o o m e d h o r n s . N o d e s c r i p t i o n n e e d b e g i v e n h e r e , s i n c e , u n l i k e S t o n e ' s s h e e p , t h e p h y s i c a l ' f e a t u r e s o f b i g h o r n s a r e w e l l k n o w n ( C o w a n i * 1 9 4 0 , M o s e r 1 9 6 2 , C o w a n a n d G u i g u e t 1 9 6 5 ) . T h e b i g h o r n s t u d y a r e a w a s t h e P a l l i s e r R a n g e a n d B a r e M o u n t a i n s i n B a n f f N a t i o n a l P a r k , A l b e r t a . I s t a y e d h e r e f r o m M a y 6 - S e p t e m b e r 1 0 , 1 9 6 3 , a n d f r o m M a y 1 9 6 4 - J u n e 1 9 6 5 . 1 0 T h e s e b i g h o r n s l i v e d i n l a r g e r p o p u l a t i o n s t h a n d i d t h e S t o n e ' s s h e e p I o b s e r v e d . T h e i r h a b i t a t w a s p r i m a r i l y o p e n , g r a s s y s l o p e s w h i c h w e r e o n c e f o r e s t e d , a n d w h i c h w e r e a g a i n b e i n g s l o w l y i n v a d e d b y f o r e s t ( F l o o k , 1 9 6 4 ) . T h e s h e e p w e r e i n m y o p i n i o n n o t l a r g e f o r b i g h o r n s ; u n f o r t u n a t e l y w e i g h t s a r e n o t a v a i l a b l e f o r t h e s t u d y a n i m a l s . T h e y e a r  l i n g s w e r e s m a l l , t h e y m a t u r e d l a t e , r e p r o d u c t i o n i n t h e y e a r s I w a s t h e r e w a s p o o r , a n d I d o n o t h e s i t a t e t o c l a s s i f y t h e s e s h e e p a s o f l o w q u a l i t y . F u r t h e r m o r e , t h e y o u n g l a m b s w e r e l i s t l e s s c o m p a r e d t o t h e S t o n e ' s l a m b s I o b s e r v e d , a n d t h e o l d e r r a m s t e n d e d t o g e t e x h a u s t e d q u i c k l y i n t h e r u t t i n g s e a s o n s . T h e s e b i g h o r n s c o n t r i b u t e d t h e b u l k o f t h e d o c u  m e n t a r y f i l m , p h o t o g r a p h s , a n d t h e m o r t a l i t y d a t a p l u s s o m e q u a n t i t a t i v e b e h a v i o u r d a t a . M E T H O D S C l a s s i f i c a t i o n o f s h e e p i n t o s e x - a g e c l a s s e s S h e e p w e r e c l a s s i f i e d o n t h e b a s i s o f h o r n - , b o d y - s i z e a n d s e x i n t o d i s t i n c t c l a s s e s , o f w h i c h I r e c o g n i z e d s e v e n i n t h e S t o n e ' s a n d D a l l ' s s h e e p s t u d y , a n d e i g h t d u r i n g t h e b i g  h o r n s t u d y . T h e s e c l a s s e s w e r e - l a m b s , f e m a l e y e a r l i n g s , a d u l t f e m a l e s , m a l e y e a r l i n g s , a d u l t r a m s o f h o r n - s i z e I , I I , I I I a n d I V . F o r S t o n e ' s a n d D a l l ' s s h e e p , c l a s s e s I a n d I I 1 1 w e r e c o m b i n e d i n t o c l a s s I I . S u c h a c l a s s i f i c a t i o n i s e s s e n t i a l i f v a r i a t i o n i n b e h a v i o u r d u e t o s e x o r a g e i s t o b e d i s c o v e r e d . T h e i n d i v i d u a l c l a s s e s w e r e c h a r a c t e r i s e d a s f o l l o w s : L a m b s : T h e s m a l l e s t s h e e p i n h o r n a n d b o d y s i z e , a g e 1 d a y t o 1 y e a r ( F i g s . 5 & 6 ) . T h e l a m b s o f S t o n e ' s a n d b i g h o r n s h e e p a r e b o r n m o u s e - g r e y , w i t h S t o n e ' s l a m b s h a v i n g a b l a c k t a i l . T h i s j u v e n i l e c o a t i s s h e d b e t w e e n A u g u s t a n d O c t o b e r a n d i s r e p l a c e d b y a c o a t s i m i l a r t o t h a t o f a d u l t s . A t s i x m o n t h s o f a g e , B a l l a n d b i g h o r n l a m b s . ( F i g s . 5 & 6 ) h a v e r a t h e r s m a l l h o r n s c o m p a r e d w i t h e q u a l a g e d e s e r t b i g h o r n l a m b s ( H a n s e n , 1 9 6 5 ) . W i t h t h e t e r m " y e a r l i n g - l a m b " , I d e n o t e s u b a d u l t s 1 1 - 1 4 m o n t h s o f a g e . T h i s c l a s s w a s n o t f u r t h e r d i f f e r e n t i a t e d b y s e x , s i n c e m a l e a n d f e m a l e a r e e x c e e d i n g l y s i m i l a r i n a p p e a r a n c e a s l a m b s . Y e a r l i n g f e m a l e : T h i s c l a s s i n c l u d e s f e m a l e s 1 4 - 2 4 m o n t h s o f a g e . T h e y a r e s o m e w h a t l a r g e r t h a n l a m b s i n h o r n a n d b o d y s i z e b u t n o t a s l a r g e a s f e m a l e s o r y e a r l i n g m a l e s . T h e y h a v e s h o r t " l a m b - l i k e " f a c e s a n d s h o r t h o r n s u s u a l l y w i t h p e r f e c t t i p s ( F i g . 7 b ) . T h e r e i s s o m e d a n g e r o f c o n f u s i n g w e l l d e v e l o p e d y e a r l i n g f e m a l e s w i t h e x c e p t i o n a l l y p o o r l y d e v e l o p e d y e a r l i n g r a m s . Y e a r l i n g f e m a l e s o c c a s i o n a l l y b e c o m e s e x u a l l y m a t u r e a t 1 8 m o n t h s o f a g e ( W o o d g e r d , 1 9 6 4 ) . 1 2 A d u l t f e m a l e : T h i s i s t h e m o s t c o m m o n c l a s s o f s h e e p . T h e y r e a c h d e f i n i t i v e a p p e a r a n c e a n d p r o p o r t i o n s s h o r t l y a f t e r 2 4 m o n t h s o f a g e a n d v a r y o n l y l i t t l e t h e r e a f t e r . T h e i r h o r n g r o w t h i s n e g l i g i b l e a n d t h e s e o r g a n s r e m a i n s m a l l . A d u l t f e m a l e s a r e t h e s t a n d a r d o f c o m p a r i s o n f o r o t h e r s h e e p c l a s s e s ( F i g . 7 c ) . Y e a r l i n g m a l e : T h i s c l a s s i s d i f f i c u l t t o d i s t i n g u i s h f r o m a d u l t , o r e x c e p t i o n a l l y w e l l d e v e l o p e d y e a r l i n g f e m a l e s . A t 1 4 m o n t h s o f a g e t h e m a l e s m a y b e s e p a r a t e d f r o m e q u a l l y a g e d f e m a l e s b y l a r g e r b o d y s i z e a n d s l i g h t l y l o n g e r , w i d e r h o r n s . T h e m a l e c o n t i n u e s t o g r o w t h r o u g h o u t s u m m e r a n d f a l l a n d , d u r i n g t h e r u t , h a s a s t r i k i n g r e s e m b l a n c e t o a d u l t f e m a l e s i n n o r m a l p o p u l a t i o n s . T h e y a r e s i m i l a r t o f e m a l e s i n b o d y s i z e , h o r n l e n g t h , a n d ( i n b i g h o r n s ) i n p o s s e s s i n g a w h i t e b e l l y . T h e y d i f f e r i n h a v i n g s l i g h t l y w i d e r h o r n b a s e s a n d m o r e d i  v e r g e n t h o r n s ; t h e i r f a c e s h a v e a m o r e l a m b - l i k e e x p r e s s i o n , t h e h a i r s o n t h e o c c i p u t a n d n e c k a r e l o n g e r t h a n i n e w e s a n d g i v e yearlong r a m s a s l i g h t l y m o r e " c h u n k y " h e a d . I n e x c e p  t i o n a l l y w e l l d e v e l o p e d m a l e s t h e t e s t e s m a y b e p l a i n l y v i s i b l e a t 1 8 m o n t h s o f a g e . T h e y d i f f e r s o m e w h a t i n b e h a v i o u r f r o m e w e s i n u s i n g t h e l o w - s t r e t c h m o r e f r e q u e n t l y . I n s o m e p o p u  l a t i o n s t h e y a r e s e x u a l l y m a t u r e a t 1 8 m o n t h s o f a g e b u t p a r  t i c i p a t e o n l y l i t t l e i n t h e r u t ( F i g s . 7 d , 8 & 9 ) . 1 3 C l a s s I r a m s : T h e s e r a m s a r e 2 6 - 3 6 m o n t h s o l d . T h e y a r e c o n s p i c u o u s l y l a r g e r i n h o r n s i z e t h a n y e a r l i n g r a m s o r a d u l t f e m a l e s , a n d i n n o r m a l , h e a l t h y p o p u l a t i o n s e x c e e d a d u l t e w e s i n b o d y s i z e ( F i g s . 7 f , 1 0 ) . A l l c l a s s I r a m s w h i c h I o b s e r v e d w e r e m a t u r e a t 3 0 m o n t h s o f a g e a n d p a r t i c i  p a t e d a c t i v e l y i n t h e r u t . O c c a s i o n a l l y , a p o o r l y d e v e l o p e d r a m o v e r 3 6 m o n t h s o f a g e w a s i n c l u d e d i n t h i s c l a s s . I n t h e S t o n e ' s s h e e p s t u d y , I i n c l u d e d t h e s e r a m s w i t h t h e n e x t l a r g e r c l a s s . C l a s s I I r a m s : R a m s 3 - 5 y e a r s o f a g e : r a r e l y 6 . T h e h o r n s h a v e f o r m e d a b o u t h a l f a n a r c b u t n o t § o f a n a r c . T h e h o r n t i p s a r e i n t a c t . T h e s e r a m s a r e l e s s c h u n k y a n d h e a v y i n a p p e a r a n c e t h a n t h e n e x t l a r g e s t r a m c l a s s e s , a l t h o u g h b o d y s i z e d i f f e r e n c e s b e t w e e n t h e s e a n d o l d e r r a m s a r e s l i g h t ( F i g . 7 g ) . C l a s s I I I r a m s : R a m s 5 - 8 y e a r s , r a r e l y 9 y e a r s o f a g e , w i t h h o r n s f o r m i n g f o f a n a r c . T h e s e a r e t h e " f c u r l s " . T h e i r h o r n t i p s a r e u s u a l l y s t i l l i n t a c t a m o n g b i g h o r n s , b u t d o s h o w t h e f i r s t s i g n s o f s p l i n t e r i n g . W h e n h o r n t i p s a r e i n t a c t , t h e t i p s a r e c l o s e t o e y e l e v e l . T h e h o r n b a s e s h a v e r e a c h e d n e a r l y u l t i m a t e t h i c k n e s s a n d t h e r a m ' s f a c i a l f e a t u r e s a r e v e r y s i m i l a r t o t h o s e o f t h e l a r g e r r a m s . I t a p p e a r s t h a t t h e i r s k u l l s h a v e r e a c h e d a l m o s t t h e i r f i n a l d i m e n s i o n s ( F i g . 7 h ) . 14 C l a s s I V r a m s : R a m s r a r e l y 7 , u s u a l l y 8 y e a r s o r o l d e r . I f h o r n t i p s a r e s t i l l i n t a c t , t h e y p r o t r u d e w e l l b e y o n d e y e l e v e l . I f h o r n t i p s a r e " b r o o m e d " ( b r o k e n ) t h e y m u s t r e a c h a l m o s t e y e l e v e l w h i l e t h e h o r n s m u s t b e v e r y h e a v y t h r o u g h o u t m o s t o f t h e i r l e n g t h a n d f o r m a n e a r p e r f e c t c i r c l e . I f t h e h o r n s w e r e h e a v i l y b r o o m e d a n d f o r m e d o n l y f o f a n a r c , a n d t h e b r o o m e d h o r n e n d s w e r e n e a r l y a s l a r g e a s t h e d i a m a t e r h a l f w a y b e t w e e n t i p a n d b a s e , I c l a s s i f i e d s u c h r a m s i n t o t h e I V c a t e g o r y . I n b o d y s i z e c l a s s I V r a m s d o n o t d i f f e r c o n  s i s t e n t l y f r o m c l a s s I I I r a m s ( F i g . 7 i ) . R a m s o f c l a s s I I I a n d I V a r e u s u a l l y d a r k e r i n c o l o u r t h a n y o u n g e r r a m s , a n d t h e i r b e l l y p a t c h i s p r o g r e s s i v e l y i n v a d e d b y b r o w n h a i r . D i f f e r e n c e s b e t w e e n P a l i ' s s h e e p a n d b i g h o r n s h e e p c l a s s e s : G e n e r a l l y s h e e p o f t h e d a l l i g r o u p h a v e l e s s h o r n g r o w t h a t e a c h c o m p a r a b l e c l a s s t h a n b i g h o r n s . T h e D a l l l a m b ( F i g . 6 ) i n f a l l c a r r i e s n o v i s i b l e h o r n s b u t t h e b i g h o r n l a m b o f c o m p a r a b l e a g e a n d d e v e l o p m e n t d o e s ( F i g . 5 ) . T h e y e a r l i n g r a m ' s h o r n s a r e t h i n n e r t h a n t h o s e o f b i g h o r n s , m a k i n g i t e v e n m o r e d i f f i c u l t t o d i s t i n g u i s h t h e s e r a m s f r o m e w e s . N o t e t h a t t h e h o r n s o f a n a v e r a g e 3 ^ y e a r o l d D a l l r a m a r e o n l y a b o u t t h e s i z e o f t h o s e f r o m a 2 ^ y e a r o l d b i g h o r n ( F i g . 3 2 ) . A m o n g r a m s I u s e d t h e s a m e h o r n s i z e c r i t e r i a t o d i s t i n g u i s h t h e v a r i o u s c l a s s e s ; t h e a g e s a l s o c o i n c i d e b e t w e e n t h e t w o s p e c i e s . 1 5 M e t h o d s o f c o l l e c t i n g d a t a A l l d a t a w a s c o l l e c t e d i n t h e f i e l d , w h e r e I l i v e d i n s i g h t o f t h e s t u d y a n i m a l s . M o s t b e h a v i o u r d a t a w a s o b t a i n e d d u r i n g o b s e r v a t i o n s a t l o n g d i s t a n c e o f s h e e p a p p a r e n t l y u n a w a r e o f t h e o b s e r v e r ' s p r e s e n c e . A l o c a l i t y w a s s e l e c t e d 6 0 0 - 2 , 0 0 0 m e t e r s f r o m t h e s h e e p w h i c h a l l o w e d a m a x i m u m o f t e r r a i n t o b e v i e w e d , s o t h a t o n e c o u l d f o l l o w v i s u a l l y a l l m o v e m e n t s o f s h e e p . A t f i r s t a t r i p o d m o u n t e d 2 5 p o w e r m o n o c u l a r s p o t t i n g s c o p e w a s u s e d . T h i s i n s t r u m e n t c a u s e d e y e s t r a i n a n d h e a d a c h e s d u r i n g c o n t i n u o u s o b s e r v a t i o n s o v e r m a n y h o u r s . L a t e r a b i n o c u l a r s p o t t i n g s c o p e , 1 5 x 6 0 w a s u s e d a n d p r o v e d t o b e c o m f o r t a b l e d u r i n g l o n g u s e . T h e m o n o c u l a r s p o t t i n g s c o p e , d u e t o i t s l i g h t w e i g h t , w a s c a r r i e d o n l o n g h i k e s a n d c o n t i n u e d t o g i v e u s e f u l s e r v i c e i n i d e n t i  f y i n g s p o t t e d s h e e p . T h e f o l l o w i n g w a s r e c o r d e d : ( 1 ) T h e n u m b e r a n d s e x - a g e c l a s s e s o f s h e e p u n d e r o b s e r v a t i o n . I a t t e m p t e d t o w a t c h n o m o r e t h a n s i x s h e e p s i m u l t a n e o u s l y . ( 2 ) A f t e r e v e r y f i v e m i n u t e s o f o b s e r v a t i o n I n o t e d t h e n u m b e r o f s h e e p f e e d i n g , s t a n d i n g , m o v i n g a b o u t , a n d r e s t i n g . T h i s m a i n t a i n e d a r e c o r d o f t h e a n i m a l s ' a c t i v i t y . 1 6 ( 3 ) E v e r y s o c i a l i n t e r a c t i o n w a s r e c o r d e d . T h e f o l l o w i n g w a s n o t e d : ( a ) T h e s e x - a g e c l a s s o f t h e s h e e p i n i t i a t i n g t h e i n t e r a c t i o n a n d t h e c l a s s o f s h e e p i t c h o s e t o i n t e r a c t w i t h . ( b ) T h e k i n d a n d s e q u e n c e o f b e h a v i o u r p a t t e r n s ( d e s c r i b e d f r o m p . 3 9 o n ) u s e d b y t h e s h e e p i n i t i a t i n g t h e i n t e r a c t i o n , a n d t h e p a t t e r n s i t r e c e i v e d i n r e p l y f r o m t h e o t h e r s h e e p . ( c ) T h e n u m b e r a n d c l a s s e s o f s h e e p w h i c h w e r e i n t h e i m m e d i a t e v i c i n i t y o f t h e s h e e p w h i c h i n i t i a t e d t h e i n t e r a c t i o n . ( d ) T h e s p e c i a l s i t u a t i o n - i f a n y - i n w h i c h t h e i n t e r a c t i o n o c c u r r e d , i . e . w h e t h e r i t t o o k p l a c e b e t w e e n t w o r a m s i n a h u d d l e , o r o u t s i d e a h u d d l e ( p . 8 6 ) , o r i n t h e p r e s e n c e o f a n e s t r o u s o r n o n - e s t r o u s e w e . L a t e r e a c h s o c i a l i n t e r a c t i o n w a s t r a n s f e r r e d t o a c o m p u t e r c a r d . T h e s e c a r d s , l a y o u t a n d p r o g r a m m e s a r e s t o r e d w i t h t h e Z o o l o g y D e p a r t m e n t , U n i v e r s i t y o f B r i t i s h C o l u m b i a , V a n c o u v e r , B . C . , C a n a d a . 3 , 8 0 0 i n t e r a c t i o n s w e r e l a t e r a n a l y s e d . I n r e c o r d i n g b e h a v i o u r , t h e i n d i v i d u a l p a t t e r n s , t h e c l a s s o f b e h a v i n g s h e e p a n d t h e i r r e s p o n s e s w e r e r e c o r d e d i n s h o r t h a n d a s t h e y t o o k p l a c e . B y b r e a k i n g d o w n b e h a v i o u r i n t o p a t t e r n s a n d r e c o r d i n g t h e s e , s u b j e c t i v e e v a l u a t i o n w a s k e p t t o 1 7 a m i n i m u m . T h u s , I w a s n o t i n t e r e s t e d w h e t h e r a r a m h a d " l o s t " o r " w o n " a n e n g a g e m e n t , h u t o n l y w h i c h b e h a v i o u r p a t t e r n s , w h e n a n d i n w h a t o r d e r h e u s e d . T h e d e c i s i o n w h e t h e r h e " l o s t " o r " w o n " w o u l d c o m e f r o m t h e f r e q u e n c i e s a n d t y p e s o f b e h a v i o u r p a t t e r n u s e d . A f e w l i n e s o f r e c o r d e d d a t a w o u l d l o o k a s f o l l o w s : " f c . L a u f I I I ( o ) , L a u f ( o ) , t w i s t I I I , I I I h o r n b . f c . / 1 0 1 5 f c . n o s e I I I " e t c . ( f c . = c l a s s I V r a m , I I I = c l a s s I I I r a m , ( o ) = n o r e s p o n s e t o t h e b e h a v i o u r p a t t e r n , L a u f = f r o n t - k i c k ( s e e p . 4 2 ) , t w i s t i s a l s o a b e h a v i o u r p a t t e r n a s i s n o s e ( l o w - s t r e t c h ) . T h e m e a n i n g o f t h i s r e c o r d i n g i s t h a t a c l a s s I V r a m k i c k e d a I I I r a m w h o d i d n o t r e s p o n d , t h e c l a s s I V r a m k i c k e d a g a i n ( n o r e s p o n s e ) t h e n t w i s t e d t o I I I . T h e c l a s s I I I r a m t u r n e d a n d h o r n e d h i s l a r g e r o p p o n e n t ' s h e a d . T h e s l a s h i n d i c a t e s t h a t f i v e m i n u t e s o f o b s e r v a t i o n a r e o v e r , a n d a n e w f i v e - m i n u t e o b s e r v a t i o n p e r i o d b e g i n s a t 1 0 . 1 5 h o u r s , e t c . ) I t w a s n o t e a s y a t f i r s t t o d e c i d e w h e n a b e h a v i o u r p a t t e r n h a d c e a s e d a n d b e g u n a n e w , s o I u s e d a r b i t r a r y c u t - o f f p o i n t s . F o r i n s t a n c e , t h e l o w - s t r e t c h i s a l o n g l a s t i n g p a t t e r n . I f a r a m w a l k e d i n l o w - s t r e t c h , s t o p p e d a n d h e l d t h e d i s p l a y i t c o u n t e d a s o n e l o w - s t r e t c h . I f h e w a l k e d o n h o w e v e r a n e w a f t e r t h e c h o s e n c o m p a n i o n , i t c o u n t e d a s t w o l o w - s t r e t c h e s . I f t h e r a m h e l d h i s d i s p l a y b u t f o l l o w e d X t i m e s , i t xv-as c o u n t e d a s X l o w - s t r e t c h e s . S h o u l d t h e r a m i n t e r r u p t 1 8 t h e d i s p l a y e v e n f o r a m o m e n t a n d t h e n r e s u m e i t , i t w a s c o u n t e d a s t w o d i s p l a y s . H o r n i n g , r u b b i n g a n d n u z z l i n g o f l a r g e r a m s b y s m a l l o n e s p r e s e n t e d a s i m i l a r p r o b l e m . I f a r a m h o r n e d h i s o p p o n e n t ' s n e c k f o r s e v e r a l m i n u t e s b u t i n t e r r u p t e d t h i s a c t i v i t y f o r a f e w s e c o n d s , s h o u l d t h i s b e r e c o r d e d a s o n e o r t w o h o r n i n g s . I r e c o r d e d i t a s t w o h o r n i n g s . I f a r a m h o r n e d w i t h o u t i n t e r r u p t i o n , i t w a s r e c o r d e d a s o n e h o r n i n g i r r e s p e c t i v e o f w h e t h e r i t l a s t e d o n e m i n u t e o r o n e s e c o n d . I n t h i s s t u d y I h a d t o i g n o r e t h e t e m p o r a l d i f f e r e n c e s b e t w e e n b e h a v i o u r p a t t e r n s s i n c e t h e s o p h i s t i c a t e d r e c o r d i n g m a c h i n e s n e c e s s a r y f o r t h i s k i n d o f r e c o r d i n g w e r e a b s e n t . T h e s e c o n d m e t h o d o f g a t h e r i n g i n f o r m a t i o n w a s t o a p p r o a c h s h e e p , f i l m a n d p h o t o g r a p h t h e i r b e h a v i o u r , a n d r e c o r d t h e s o u n d s a n d m i n o r p a t t e r n v a r i a t i o n s w h i c h e s c a p e d m e a t a d i s t a n c e . F o r f i l m i n g I u s e d a B o l e x R . X 1 6 w i t h 2 5 , 7 5 a n d 1 5 0 mm l e n s e s , a n d t h e l i g h t h a n d y t r i p o d o f t h e s a m e . m a k e . T h e s t i l l c a m e r a s w e r e s i n g l e l e n x r e f l e x , P e n t a x H 2 a n d S V m o d e l w i t h 5 0 , 2 0 0 a n d 4 0 0 mm l e n s e s . T h e 2 0 0 mm T a k u m a r l e n s I u s e d m o s t f r e q u e n t l y . W h e n f i l m i n g few n o t e s w e r e t a k e n a n d t h e s e w e r e e x c l u d e d f r o m t h e q u a n t i t a t i v e a n a l y s i s t o c o u n t e r t h e a r g u m e n t t h a t m y p r e s e n c e a d v e r s e l y a f f e c t e d t h e b e h a v i o u r o f s h e e p . I d e t e c t e d n o s u c h i n f l u e n c e d e s p i t e m a n y h o u r s o f o b s e r v i n g 1 9 s h e e p a t l o n g a n d s h o r t r a n g e . S u c h n o t e s w e r e u s e d t o g e t h e r w i t h f i l m s a n d p h o t o s . t o d e s c r i b e t h e v a r i o u s b e h a v i o u r p a t t e r n s m o r e a c c u r a t e l y . O n t h e S t o n e ' s s h e e p s t u d y a r e a 3 6 s h e e p w e r e r e c o g n i z e d i n d i v i d u a l l y b y d i f f e r e n c e s i n c o a t p a t t e r n i n g , c o l o u r a n d h o r n s h a p e ( P i g . 4 ) . S i n c e f e w s h e e p w e r e p r e s e n t , a n d t h e m a r k i n g s w e r e d i s t i n c t , I c o u l d q u i c k l y r e c o g n i z e i n d i v i d u a l s , a n d r e c o g  n i z e d t h e m e q u a l l y q u i c k l y a f t e r a l m o s t t h r e e y e a r s o f a b s e n c e f r o m t h e s t u d y a r e a . E a c h k n o w n s h e e p w a s i d e n t i f i e d b y l e t t e r ( i . e . D - r a m ) a n d a r e c o r d w a s k e p t o f w h e r e a n d w h e n i t m i g r a t e d a n d w i t h w h o m i t i n t e r a c t e d . I n B a n f f P a r k , a l a r g e n u m b e r o f b i g h o r n s h a d b e e n t a g g e d w i t h s m a l l a l u m i n i u m t a g s b y t h e l a t e w a r d e n , M r . J . E . S t e n t o n . I n d i v i d u a l s c o u l d b e r e c o g n i z e d b y t h e p r e s e n c e a n d n u m b e r o n t h e t a g , a m e t h o d w h i c h w a s n o m o r e r e l i a b l e t o m e t h a n i d e n t i  f y i n g / s h e e p b y t h e i r p e r s o n a l f e a t u r e s . A t l o n g d i s t a n c e , h o w e v e r , I f o u n d b i g h o r n s m o r e d i f f i c u l t t o i d e n t i f y t h a n S t o n e ' s s h e e p . T h e a g e o f r a m s w a s d e t e r m i n e d b y c o u n t i n g h o r n s e g m e n t s ( G e i s t 1 9 6 6 a ) . T h e h o r n s e g m e n t s o f S t o n e ' s a n d D a l l s h e e p a r e m u c h m o r e c l e a r l y v i s i b l e t h a n t h o s e o f b i g h o r n s ( F i g . ) . O n a c l e a r d a y w i t h o u t m i r a g e , u s i n g a 2 5 p o w e r s p o t t i n g s c o p e o n a s o l i d r e s t , t h e y m a y b e s e e n a s f a r a w a y a s 6 0 0 y a r d s . A c c u r a t e c o u n t s c a n b e m a d e a t a b o u t 4 0 0 y a r d s o n r a m s e i g h t 2 0 y e a r s o f a g e o r l e s s . S i n c e h o r n s e g m e n t s d e c r e a s e r a p i d l y i n s i z e a f t e r 7 y e a r s o f a g e , s o m e m e r g e w i t h t h e h a i r l i n e c l o s e t o t h e h o r n , o r a r e c a m o u f l a g e d b y d e e p g r o o v e s o n t h e b a s a l p a r t o f t h e h o r n s . T h e f o l l o w i n g f o u r S t o n e ' s r a m s w h i c h h a d b e e n a g e d p r i o r t o t h e i r d e a t h f e l l i n t o m y h a n d s . E s t i m a t e d A c t u a l A g e R a m A g e ( c h e c k e d o n d e a d a n i m a l ) D - r a m 1 1 y r s . + 1 4 y e a r s " f c " 1 0 y r s . 1 2 y e a r s C l i f f - r a m 1 0 y r s . 1 0 y e a r s U n n a m e d b u t k n o w n r a m 8 y r s . 9 y e a r s I t c a n b e s e e n t h a t e v e n w i t h v e r y o l d r a m s a f a i r e s t i m a t e o f t h e i r a g e m a y b e o b t a i n e d . I n B a n f f P a r k , t i m e w a s d e v o t e d t o t h e s e a r c h f o r d e a d s h e e p . A r e c o r d w a s k e p t o f t h e a g e o f e a c h s h e e p , t h e l e n g t h a n d b a s a l c i r c u m f e r e n c e s o f r a m h o r n s , a n d t h e l e n g t h s o f e a c h h o r n s e g m e n t . H o r n s e g m e n t l e n g t h w a s m e a s u r e d f r o m g r o o v e t o g r o o v e o n t h e o u t s i d e e d g e o f e a c h h o r n . S i m i l a r m e a s u r e m e n t s w e r e m a d e f r o m a l l h o r n s c o l l e c t e d o f a l l s h e e p s p e c i e s . T h e r e a r e a f e w c o n s i d e r a t i o n s a b o u t w o r k i n g w i t h s h e e p w h i c h s h o u l d b e p l a c e d o n r e c o r d . W i l d s h e e p c a n b e t a m e d e a s i l y . I b e c a m e a w a r e o f i t f i r s t o n t h e S t o n e ' s s h e e p s t u d y a r e a w h e n , d r e s s e d i n w h i t e o v e r a l l s a n d m o v i n g s l o w l y , i t w a s 2 1 p o s s i b l e t o g e t i n t o g o o d f i l m i n g d i s t a n c e . L a t e r , s o m e r a m s w e r e u n d i s t u r b e d b y m y c l o s e p r e s e n c e a n d e v e n l a y d o w n w i t h o u t l o o k i n g a t m e . I t w a s i n B a n f f P a r k t h a t I b e c a m e f u l l y a w a r e o f h o w t a m e m o u n t a i n s h e e p c a n b e c o m e a n d s t i l l l i v e i n t h e w i l d s t a t e . F o r t h i s I a m g r a t e f u l t o t h e l a t e J . E . S t e n t o n , P a r k W a r d e n o f B a n k h e a d D i s t r i c t . H e h a b i t u a t e d s h e e p t o l i c k r o c k s a l t i n h i s h a n d a n d w h i l e t h e y l i c k e d h e c l a m p e d o n e a r t a g s . T h e P a l l i s e r s h e e p c o m e i n t o t o u c h w i t h h u m a n s o n l y a t L a k e M i n n e w a n k a o n a f e w o c c a s i o n s d u r i n g t h e s u m m e r . Y e t t h e y r e t a i n e d t h e i r t a m e n e s s . B e t w e e n 1 9 6 3 t o 1 9 6 5 I c l i m b e d t o t h e s e s h e e p r e g u l a r l y . W h i l e o f f e r i n g s a l t o n e c o u l d , w i t h c a u t i o n , f r e e t h e h a i r s f r o m t h e e a r t a g s a n d a f t e r s o m e m a n i p u l a t i o n o f t h e e a r , r e a d m o s t t a g s . S h e e p w h i c h w e r e q u i t e - w i l d a t t h e b e g i n n i n g o f t h e b i g h o r n s t u d y s o o n t a m e d a n d c o u l d a l s o b e h a n d l e d . D u r i n g f a l l , 1 9 6 5 , I o b s e r v e d D a l l ' s s h e e p w h i c h l i v e d c l o s e t o t h e A l a s k a h i g h w a y a n d w e r e s o m e w h a t h a b i t u a t e d t o t h e c a r s a n d h u m a n s o n t h e r o a d b e l o w . T h e y w e r e a l i t t l e w i l d a t f i r s t b u t a f t e r t h r e e w e e k s t h e y w e r e t o l e r a n t e n o u g h t o l e t m e s t a n d w i t h i n 2 5 - 3 0 p a c e s . I t w o u l d h a v e t a k e n l i t t l e m o r e e f f o r t a n d t i m e t o t a m e t h e m e n t i r e l y . W e l l e s a n d W e l l e s ( 1 9 6 1 ) d e s c r i b e r a t h e r s i m i l a r e x p e r i e n c e s w i t h d e s e r t s h e e p i n D e a t h V a l l e y , C a l i f o r n i a . I t c a n b e s a f e l y s u g g e s t e d t h a t a n y u n l i m i t e d s h e e p p o p u l a t i o n m a y b e t a m e d a n d s t u d i e d . 2 2 P A R T I D E S C R I P T I O N S O F B E H A V I O U R P A T T E R N S O F S H E E P I n t r o d u c t i o n T h e " b e h a v i o u r p a t t e r n s o f s h e e p c a n h e g r o u p e d i n t o t h r e e m a j o r c a t e g o r i e s . T h e s e a r e h a b i t a t b e h a v i o u r , b o d y c a r e b e h a v i o u r a n d s o c i a l b e h a v i o u r . H a b i t a t b e h a v i o u r i s d i r e c t e d a t t h e p h y s i c a l e n v i r o n m e n t o f t h e a n i m a l - i t s h a b i t a t . B o d y c a r e b e h a v i o u r i s d i r e c t e d m a i n l y a t t h e a n i m a l ' s o w n b o d y , w h i l e s o c i a l b e h a v i o u r i s d i r e c t e d a t o t h e r m e m b e r s o f t h e s a m e s p e c i e s . S o c i a l b e h a v i o u r p a t t e r n s h a v e m e a n i n g t o c o n s p e c i f i c s , i n s o f a r a s t h e s e m a y r e s p o n d p r e d i c t a b l y , b u t s o m e p a t t e r n s a r e u n d e r s t o o d b e y o n d t h e s p e c i e s l i m i t , s u c h a s t h r e a t b e h a v i o u r . I n t h i s t h e s i s , s o c i a l b e h a v i o u r i s o f m a j o r c o n c e r n . H o w d o e s o n e r e c o g n i z e s o c i a l p a t t e r n s ? T h e y a p p e a r t o d i f f e r f r o m " n o r m a l " s t a n c e s a n d a c t i o n s b y v e r y s p e c i f i c d e v i a t i o n s . N o r m a l m o v e m e n t s a r e s l o w a n d r e l a x e d , n e v e r r i g i d . A r i g i d s t a n c e c a n b e j u s t a s c o n s p i c u o u s a s i t s c o n  v e r s e a n d s e r v e s - a s a r a t h e r d i s t u r b i n g s i g n a l t o s h e e p ( F i g . 2 7 ) . S o c i a l b e h a v i o u r p a t t e r n s d e v i a t e f r o m n o r m a l b e h a v i o u r b y u n u s u a l c o n f o r m a t i o n s o f b o d y p a r t s , b y f a s t e r , j e r k i e r o r s l o w e r a n d s t i f f e r m o v e m e n t s t h a n n o r m a l , b y n o n - r a n d o m 2 3 o r i e n t a t i o n s t o w a r d s c o n s p e c i f i c s a n d b y t h e r e l e a s e o f s p e c i f i c s o u n d s a n d o d o u r s . U l t i m a t e l y , a s o c i a l b e h a v i o u r p a t t e r n m u s t h a v e s o m e e f f e c t o n t h e c o n s p e c i f i c i t i s s h o w n t o ; i t m u s t h a v e s o m e " s o c i a l m e a n i n g " . U n f o r t u n a t e l y , t h e r e ' i s n o s i m p l e w a y t o d e t e r m i n e t h i s " m e a n i n g " o b j e c t i v e l y . I t a p p e a r s t h o u g h t h a t i t c o u l d b e d e t e r m i n e d o b j e c t i v e l y b y c o m p a r i n g a n o r m a l r a n k o r d e r i n g o f b e h a v i o u r w i t h a s i m i l a r r a n k o r d e r r e c o r d e d a f t e r t h e o c c u r r e n c e o f a s o c i a l b e h a v i o u r p a t t e r n . T h e m e a n i n g o f t h e '.. s o c i a l p a t t e r n s h o u l d b e i n v e r s e l y p r o p o r t i o n a l t o t h e c o r r e l a t i o n c o e f f i c i e n t o f t h e t w o r a n k o r d e r s . I n t h i s s t u d y I d e t e r m i n e d s o c i a l b e h a v i o u r p a t t e r n s s u b j e c t i v e l y . S h e e p h a v e s o m e w h a t m o r e l i m i t e d m e a n s o f s o c i a l e x p r e s s i o n t h a n o t h e r m a m m a l s . U n l i k e m o o s e o r d e e r , t h e y c a n n o t r a i s e a m a n e o n t h e n e c k o r e r e c t t h e b o d y h a i r . T h e i r e a r s a r e v e r y s m a l l a n d a l t h o u g h t h e y d o a s s u m e c h a r a c  t e r i s t i c p o s i t i o n s , t h e y c h a n g e t h e a p p e a r a n c e o f s h e e p l i t t l e . A, f l i c k o f t h e e a r c a n m a r k e d l y a l t e r t h e a p p e a r a n c e o f a c o w m o o s e o r d e e r , b u t n o t o f s h e e p . U n l i k e p r i m a t e s o r c a r n i  v o r e s , s h e e p h a v e a l m o s t n o f a c i a l e x p r e s s i o n s s a v e f o r s l i g h t c h a n g e s w h e n c l o s i n g t h e e y e s o r d i l a t i n g t h e n o s t r i l s . H o w e v e r , s h e e p a p p e a r t o u s e t h e i r t o n g u e f o r v i s u a l a n d t a c t i l e e x p r e s s i o n . 2 4 A l l c o l o u r e d A m e r i c a n s h e e p h a v e l a r g e , w h i t e r u m p p a t c h e s a n d a w h i t e n o s e . S e x u a l l y m a t u r e r a m s , i n p a r  t i c u l a r , h a v e a p r o n o u n c e d w h i t e m u z z l e . T h e s e s h a d e p a t t e r n s a r e m o s t c o n s p i c u o u s i n f a l l a n d e a r l y w i n t e r w h e n s h e e p c a r r y t h e i r d a r k e s t c o a t . S i n c e t h e g u a r d h a i r s a r e v e r y b r i t t l e ( e x c e p t o n t h e f a c e ) t h e c o a t b e c o m e s w o r n i n w i n t e r a n d b e c o m e s p r o g r e s s i v e l y l i g h t e r . T h u s a r a m c r o s s i n g t h r o u g h s o m e t h i c k d w a r f b i r c h o n e D e c e m b e r m o r n i n g , l e f t a s h o w e r o f b r o k e n h a i r s i n h i s t r a c k s . I n s p r i n g s o m e b i g h o r n e w e s w e r e s o l i g h t t h a t t h e r u m p p a t c h d i s a p p e a r e d ( F i g . 2 4 ) . I n a d d i t i o n , r a m s a r e s t r i k i n g l y d i f f e r e n t i a t e d a n t e r i o r l y b y t h e i r l a r g e h o r n s . H e n c e , s h e e p t e n d t o b e m o s t c o n s p i c u o u s l y m a r k e d a n t e r i o r l y a n d p o s t e r i o r l y d u r i n g e a r l y w i n t e r . T h e p r i m a r y o r g a n s o f e x p r e s s i o n f o r s h e e p a r e i t s h e a d a n d n e c k , a n d , t o a n u n d e t e r m i n e d e x t e n t , i t s c o a t p a t t e r n i n g . B e f o r e c o n c e n t r a t i n g o n t h e s o c i a l b e h a v i o u r , i t a p p e a r s i m p o r t a n t t o u n d e r s t a n d w h a t r e l a t i o n s h i p h a b i t a t a n d b o d y c a r e b e h a v i o u r h a v e h a d t o t h e e v o l u t i o n o f s h e e p . H e n c e a s h o r t d e s c r i p t i o n o f t h e s e b e h a v i o u r a l a d a p t a t i o n s w i l l p r e c e d e t h a t o f s o c i a l b e h a v i o u r . 2 5 H a b i t a t b e h a v i o u r T h e h a b i t a t a d a p t a t i o n s o f D a l l a n d b i g h o r n s h e e p a r e t h o s e o f a g e n e r a l i s e d m o u n t a i n e e r , c a p a b l e o f r u n n i n g a t g r e a t s p e e d o v e r s h o r t d i s t a n c e s , w h o v j u m p s r a t h e r t h a n c l i m b s i n t r e a c h e r o u s t e r r a i n , b u t w h o i s s p e c i a l i z e d t o g r a z i n g w h i c h i n t u r n r e s t r i c t s h i m t o a r e a s w i t h l o w w i n t e r s n o w . T h e h a b i t a t , a n d t o a s m a l l e x t e n t t h e s o c i a l b e  h a v i o u r o f s h e e p i s i n f l u e n c e d b y t h i s c e n t r a l t h e m e i n i t s a d a p t a t i o n s . S h e e p a r e n o r m a l c r o s s - w a l k e r s , w h i c h m a n y g a z e l l e s a r e n o t ( W a l t h e r , 1 9 5 8 ) . U n l i k e m o u n t a i n g o a t s , s h e e p q u i c k l y b e g i n t r o t t i n g o r b o u n d i n g , w h e r e a s t h e g o a t t e n d s t o w a l k e v e n w h e n e s c a p i n g . A m e r i c a n s h e e p a r e s u p e r b j u m p e r s a n d t r a v e r s e c l i f f t e r r a i n o f t e n i n t h i s m a n n e r . T h e l a r g e O v i s a m m o n p o l i i s a p p a r e n t l y a p o o r j u m p e r a n d c l i m b e r , w h o i n c o n f i n e m e n t s h u n s r o c k y t e r r a i n - u n l i k e i b e x o r m a r k h o r ( C a p r a i b e x a n d C . f a l c o n e r ! ) . S h e e p t r a v e l l i n g o n b r i t t l e s n o w c r u s t s s p r e a d t h e i r l e g s a n d p l a c e h o o v e s a n d d e w - c l a w s s i m u l t a n e o u s l y o n t h e s u r f a c e . T h e m a n n e r i n w h i c h E u r a s i a n w i l d s h e e p l i e d o w n a n d r i s e h a s b e e n d e s c r i b e d b y L a r m i e r - T a n n e r ( 1 9 6 5 ) ; A m e r i c a n s h e e p f o l l o w t h e s a m e p a t t e r n . 2 6 T h e r e s t i n g p o s i t i o n s o f s h e e p s h o w s o m e v a r i a b i l i t y o f l e g p l a c i n g , b u t a r e l e s s v a r i a b l e t h a n t h o s e o f d e e r ( O d o c o i l e u s ) o r m o o s e ( A l c e s ) . T h e y r a r e l y r e s t w i t h a l l f o u r l e g s s t r e t c h e d f r o m t h e b o d y ; I h a v e n e v e r s e e n s h e e p l i e f l a t o n t h e i r s i d e s a s m o o s e ( G e i s t , 1 9 6 3 ) o r d e e r ( F i g . l l ) o c c a s i o n a l l y d o . D u r i n g c o l d w e a t h e r s h e e p d r a w t h e i r l e g s t i g h t l y a g a i n s t t h e i r b o d y ( F i g . 1 2 ) , b u t e x t e n d t h e m o f t e n i n w a r m w e a t h e r . S o m e r e s t w i t h t h e m u z z l e o r a h o r n t i p p l a c e d o n t h e g r o u n d . S h e e p t e n d t o r e s t t o g e t h e r a n d t o u s e t h e s a m e b e d s r e p e a t e d l y ( F i g . 1 3 ) . S m a l l l a m b s f r e q u e n t l y r e s t u p h i l l c l o s e t o t h e i r e w e ( F i g . 1 4 ) . T h e p r e r e q u i s i t e s o f b e d d i n g s i t e s a r e l e v e l a r e a s l a r g e e n o u g h t o h o l d a s h e e p , a n d g o o d v i s i b i l i t y . S h e e p m a y r e s t a t n i g h t h i g h i n t h e c l i f f s , p a r t i c u l a r l y d u r i n g s p r i n g . I n c o n t r a s t t o s h e e p , m o o s e r a r e l y u s e t h e s a m e b e d t w i c e i n w i n t e r ( D e s M e u l e s , 1 9 6 4 ) . M o o s e s l u m p i n t o d e e p s n o w t o r e s t a n d p a r t i a l l y b u r y t h e m s e l v e s ( F i g . 1 5 ) . T h e d e e p , f l u f f y s n o w a p p a r e n t l y s e r v e s a s i n s u l a t i o n a n d t h u s i n h e a t c o n s e r v a t i o n . D e s M e u l e s n o t e d t h a t m o o s e l e f t a n a r e a , o n c e t h e s n o w w a s t r a m p l e d a n d s e a r c h e d o u t a r e a s w i t h f l u f f y d e e p s n o w . I h a v e n o t s e e n s h e e p u s e s n o w i n t h i s m a n n e r . H o w e v e r , t h e y d o g o i n t o c a v e s t o r e s t d u r i n g c o l d w i n t e r d a y s , o r s e a r c h o u t c r a c k s i n c l i f f s . 2 7 A n i m p o r t a n t a d a p t a t i o n o f s h e e p i s s c r a t c h i n g . I t i s u s e d t o p a w b e d s , w h i c h d u e t o c o n t i n u o u s u s e , b e c o m e e n l a r g e d b y t h i s a c t i v i t y . S c r a t c h i n g r e m o v e s t h e r o c k s a n d p e b b l e s w h i c h h a v e r o l l e d d o w n t h e s l o p e o n t o t h e b e d . T h i s i s d e m o n s t r a t e d b y a D a l l ' s e w e i n F i g . 1 0 . A f t e r t h e b e d h a d b e e n c l e a n e d t o t h e s o f t s a n d , t h e e w e l a y d o w n . Y e t , a s W a l t h e r ( 1 9 6 1 ) c o r r e c t l y p o i n t e d o u t , p a w i n g i s n o t a n i n t e l l i g e n t l y p e r f o r m e d b e h a v i o u r , f o r s h e e p p a w o n a n y s o r t o f s u b s t r a t e p r i o r t o r e s t i n g , b e i t s h e e r r o c k , s o f t g r a s s , o r a c o n c r e t e p l a t e . I o b s e r v e d t h a t l a m b s 7 d a y s o f a g e b e g a n t o p a w f o r t h e f i r s t t i m e . T h e y i n c o r p o r a t e d i t i n t o p l a y . T h e y p a w e d , j u m p e d , a n d f r o l i c k e d , p a w e d , j u m p e d , e t c . I h a v e s e e n o n e l a m b p a w a b e d , t h e n s t e p t h r e e p a c e s f o r w a r d a n d l i e d o w n . T h e s e a n i m a l s u s e d p a w i n g , b u t n o t w i t h a n y a p p a n e n t i n s i g h t . T h i s i s f u r t h e r i n d i c a t e d b y a d u l t s h e e p a t t e m p t i n g t o r e m o v e c o n s p e c i f i c s f r o m a s a l t b l o c k b y p a w i n g t h e i r b a c k s . T h e s a m e b e h a v i o u r i s u s e d t o g e t a c o n s p e c i f i c t o v a c a t e a b e d ( F i g . 1 7 ) . S h e e p p a w c r a t e r s i n t o t h e s n o w b l a n k e t ( F i g . 1 8 ) a n d f e e d o n t h e u n c o v e r e d g r a s s e s . P a w i n g i s v e r y s t e r e o t y p e d i n s h e e p a n d i s u s e d f r e q u e n t l y i n w i n t e r a s l o n g a s t h e v e g e t a t i o n i s c o v e r e d b y s o f t s n o w . O t h e r r u m i n a n t s f o u n d i n t h e m o u n t a i n s , s u c h a s m o u n t a i n g o a t , d e e r ( O d o c o i l e u s  h e m i o n u s ) . e l k ( C e r v u s c a n a d e n s i s ) a n d m o o s e a l s o r e s o r t t o 2 8 p a w i n g s n o w f r o m v e g e t a t i o n ; o f t h e f o u r s p e c i e s m e n t i o n e d m o o s e d o i t l e a s t o f t e n . P a w i n g t h e s n o w " b l a n k e t f r o m f o r a g e i s , h o w e v e r , h y n o m e a n s u n i v e r s a l . B u f f a l o ( B i s o n ) , l i k e c a t t l e , d o n o t p a w b u t p u s h t h e s n o w a w a y w i t h t h e i r s n o u t s ( F u l l e r , 1 9 6 0 ) . I s h a l l d e s c r i b e t h e h o m e r a n g e a n d m i g r a t i o n c h a r a c t e r i s t i c s o f s h e e p , a s w e l l a s s o m e o f t h e i r o t h e r h a b i t a t b e h a v i o u r e l s e w h e r e . B o d y c a r e b e h a v i o u r T h e p e c u l i a r i t i e s o f t h e c o a t o f m o u n t a i n s h e e p a p p e a r t o b e r e l a t e d t o c e r t a i n c h a r a c t e r i s t i c s o f t h e i r c o m f o r t m o v e m e n t s . S h e e p h a v e l o n g , b r i t t l e g u a r d - h a i r s u n d e r l a i d b y a n a b u n d a n c e o f f i n e w o o l . U n l i k e m u l e d e e r , m o u n t a i n s h e e p a p p e a r t o h a v e o n l y o n e m o u l t p e r y e a r . R y d e r ( i 9 6 0 ) f o u n d f o r m o u f l o n ( 0 . m u s i m o n ) t h a t t h e r e i s o n e c o n s p i c u o u s s p r i n g m o u l t w h e n t h e p r i m a r i e s ( g u a r d h a i r s ) a n d t h e s e c o n d a r i e s ( w o o l ) a r e s h e d , a n d t h a t a s e c o n d p e a k o f p r i m a r y s h e d d i n g a p p e a r s i n f a l l . T h e s a m e m a y b e t r u e f o r A m e r i c a n s h e e p , h o w e v e r , o n l y t h e s p r i n g m o u l t i s c o n  s p i c u o u s . T h e m o u l t i s a m o s t s t r i k i n g e v e n t . T h e h a i r c o m e s o f f i n m a t t e d b u n c h e s a n d m a y h a n g l i k e t o w e l s a b o u t t h e a n i m a l ( F i g . 1 9 ) . T h e f i r s t s i g n o f m o u l t a p p e a r s i n M a r c h 2 9 b u t t h e s h e e p a r e n o t c o m p l e t e l y s h e d u n t i l J u l y . I t i s d u r i n g t h e m o u l t t h a t s h e e p s h o w o c c a s i o n a l l y f r a n t i c c o m  f o r t m o v e m e n t s , f r o m w h i c h o n e c a n i n f e r t h a t t h e l o s s o f h a i r i s a s s o c i a t e d w i t h s o m e d i s c o m f o r t . T h e m o s t c o m m o n c o m f o r t m o v e m e n t i n s p r i n g i s b o d y r u b b i n g . S h e e p m o v e t o r o c k o u t c r o p p i n g s , d e a d t r e e s , s m a l l b u s h e s , c o a r s e r u b b l e f i e l d s o r e r o s i o n s i t e s a n d p r o c e e d t o r u b h a r d a g a i n s t t h e r o u g h s u r f a c e s . T h e y p o l i s h t h e i r s i d e s , s h o u l d e r s a n d r e a r e n d s b a c k a n d f o r t h a g a i n s t t h e o b s t a c l e . T h e h a i r i s n o t a l w a y s r u b b e d o f f b u t b r o k e n o f f , r e s u l t i n g i n s t r i p s a n d s p o t s o f o l d h a i r b a s e s s t i l l f i r m l y e m b e d d e d i n f i e l d s o f n e w l y g r o w i n g o n e s ( F i g . 7 c ) . I h a v e n e v e r s e e n e l k , m o o s e o r m u l e d e e r a c t l i k e s h e e p d o , b u t n e i t h e r d o t h e s e c e r v i d s h a v e a m o u l t i n w h i c h t h e m a t t e d g u a r d h a i r a n d w o o l c o m e s o f f i n s t r i p s a n d d e c o r a t e s t h e c o u n t r y s i d e w h e r e v e r t h e y g o . F r o m 6 5 0 c o m f o r t m o v e m e n t s o f r a m s c o u n t e d i n s p r i n g 1 9 6 4 , 2 6 3 ( 4 0 . 5 $ ) w e r e b o d y r u b b i n g . T h e m o u l t i s g r e a t l y a c c e l e r a t e d o n t h e w i t h e r s o f s m a l l h o r n e d s h e e p . T h i s a p p e a r s t o b e d u e t o t h e p r e s e n c e o f t h e t i c k ( D e r m a c e n t o r a n d e r s o n i ) . S h e e p s c r a t c h t h e i r w i t h e r s w i t h t h e i r h o r n t i p s a n d r e m o v e w i t h i t h a i r a n d s c a b s ( F i g . 2 0 ) . T h e w h o l e u p p e r s h o u l d e r r e g i o n m a y b e l a i d o p e n a n d b e f u l l o f s m a l l s c a b s a n d r o u n d , w h i t i s h m a r k s w h e r e t i c k s a p p a r e n t l y a t t a c h e d , b r o k e n b r u s h e s o f g u a r d h a i r , e n g o r g e d 3 0 a n d a c t i v e l y c r a w l i n g t i c k s ( F i g . 2 1 ) . T h e t i c k s w e r e s u r p r i s i n g l y l o o s e i n t h e s k i n . T h o s e w h i c h I p l u c k e d o u t c a m e a w a y w i t h a s c a b . W i t h e r s c r a t c h i n g w i t h a h o r n w a s t h e n e x t m o s t c o m m o n c o m f o r t m o v e m e n t f o r i t o c c u r r e d i n 6 5 0 c o m f o r t m o v e m e n t s 1 5 1 ( 2 4 . 0 $ ) t i m e s . A. m o s t c o m m o n m e t h o d o f s c r a t c h i n g i s w i t h a h i n d l l e g . S h e e p s c r a t c h t h e c h e s t , u p p e r f r o n t l e g s , n e c k a n d h e a d i n t h i s m a n n e r . I t o c c u r r e d 1 4 6 t i m e s i n 6 5 0 c o m f o r t m o v e m e n t s . S h e e p u s e t h e i r t o n g u e a n d t e e t h l e s s c o m m o n l y . S u c h c o m  f o r t m o v e m e n t o c c u r r e d o n l y 7 9 o u t o f 6 5 0 t i m e s , w h i l e s h a k i n g t h e b o d y - a m e t h o d o f o r d e r i n g t h e h a i r c o a t - o c c u r r e d o n l y 1 1 t i m e s . W i t h t h e i r m o u t h , s h e e p w o r k o v e r f r o n t a n d h i n d l e g s , t h e f l a n k s a n d o c c a s i o n a l l y h a u n c h e s . T h e r e a r e o t h e r c o m f o r t m o v e m e n t s w h i c h h a v e n o t h i n g t o d o w i t h g r o o m i n g o r c a r e o f b o d y s u r f a c e . S h e e p y a w n , a s d o d e e r a n d m o o s e . T h e y s t r e t c h a f t e r r e s t i n g p e r i o d s ( F i g . 2 2 ) . H o w e v e r , I h a v e n o t s e e n s h e e p h u n c h t h e i r b a c k s i n a s t r e t c h a s m o o s e , e l k a n d m u l e d e e r o c c a s i o n a l l y d o ( G e i s t , 1 9 6 6 b , F i g . 1 ) . T h e y d o s t r e t c h t h e i r n e c k w h i l e p u l l i n g i n t h e c h i n s h a r p l y . T h e u r i n a t i o n a n d d e f e c a t i o n p o s t u r e s o f s h e e p a r e s i m i l a r t o o t h e r b o v i d s b u t d e v i a t e f r o m t h o s e o f t e l e m e t e - c a r p a l i a n d e e r ( G e i s t , 1 9 6 6 b ) . D e f e c a t i o n o c c u r s f r o m a n e a r n o r m a l p o s t u r e , o n l y t h a t t h e t a i l i s r a i s e d . S h e e p d o n o t u s u a l l y i n t e r r u p t t h e a c t i v i t y i n w h i c h t h e y a r e e n g a g e d 3 1 w h e n d e f e c a t i n g . T h e u r i n a t i o n p o s t u r e s o f t h e t w o s e x e s v a r y g r e a t l y . E w e s s q u a t a n d u r i n a t e b a c k w a r d s w i t h a r a i s e d t a i l ( F i g . 2 3 ) . T h i s p o s t u r e d o e s h a v e s o m e s o c i a l s i g n i f i c a n c e . R a m s s t a n d a l m o s t n o r m a l l y , t h e i r h i n d l e g s a r e o n l y a l i t t l e f a r t h e r b a c k a n d t h e b a c k i s d e p r e s s e d s l i g h t l y . T h e e v i d e n c e s u g g e s t s t h a t c o m f o r t m o v e m e n t s h a v e t h e i r o w n s p h e r e o f s e l e c t i o n a n d e v o l v e q u i t e i n d e p e n d e n t l y o f s o c i a l - o r h a b i t a t a d a p t a t i o n s . F o r i n s t a n c e , m o u n t a i n g o a t s a n d s h e e p h a v e r a t h e r s i m i l a r h a b i t a t a d a p t a t i o n s a l t h o u g h t h e y e m p h a s i z e v a r i o u s a d a p t a t i o n s w i t h i n t h i s c a t e g o r y d i f f e r e n t l y . B o t h f e e d o n l o w h e r b a c e o u s v e g e t a t i o n , b u t t h e s h e e p i s s p e c i a l i z e d f o r i t a n d h a s t h e l o n g e r , s u b - h y p s o d o n t m o l a r s . B o t h p a w t o r e m o v e s n o w f r o m v e g e t a t i o n , a l t h o u g h t h e g o a t i s m o r e e f f i c i e n t . B o t h a v o i d t h e c o l d e a r l y m o r n i n g s b y b e c o m i n g a c t i v e l a t e r i n t h e d a y . B o t h f r e q u e n t p r e c i p i t o u s t e r r a i n b u t w h e r e a s t h e g o a t c l i m b s p r i m a r i l y , t h e s h e e p j u m p s q u i t e f r e q u e n t l y . H o w e v e r , i n t h e i r c o m f o r t m o v e m e n t s , s h e e p a n d m o u n t a i n g o a t d i f f e r g r e a t l y , a s i n t h e i r s o c i a l a d a p t a t i o n s ( G e i s t , 1 9 6 4 ) . M o u n t a i n g o a t s s h o w c o m f o r t m o v e m e n t s e x c e e d i n g l y r a r e l y , a n d x v h e y t h e y d o s o , t h e y a p p e a r c l u m s y a n d i n e p t . B u t g o a t s s a n d b a t h e . T h e y d i g i n d r y s a n d y s o i l a n d t h r o w i t o v e r t h e i r f l a n k s a n d h a u n c h e s . T h e i r c o a t o f l o n g g u a r d 3 2 h a i r s a n d w o o l i s i m p r e g n a t e d w i t h s a n d . T h e f u r o n t h e g o a t ' s b o d y i s v e r y l o n g a n d d e n s e , w h i c h r a i s e s t h e q u e s t i o n o f w h e t h e r s c r a t c h i n g o r n i b b l i n g w o u l d b e a n e f f i c i e n t m a n n e r o f r e a c h i n g t h e s k i n s u r f a c e . S a n d b a t h i n g a p p e a r s t o h a v e t a k e n t h e r o l e p l a y e d b y t h e m o v e m e n t s c o n n e c t e d w i t h b o d y s u r f a c e c a r e ( E i s e h b e r g , p e r s o n a l c o m m . ) . A . s w a s n o t e d e a r l i e r , d e e r a n d m o o s e d o n o t r u b o f f t h e i r h a i r c o a t s . H o w e v e r , t h e y p o s s e s s c o m f o r t m o v e m e n t s s h e e p d o n o t h a v e . W h e n t h e a n t l e r s a r e i n v e l v e t , d e e r a n d m o o s e r u b t h e a n t l e r t i p s u n d e r t h e r a i s e d h i n d l e g . W h e r e a s s h e e p c o m m o n l y u s e t h e h o r n s t o s c r a t c h w i t h e r s o r s h o u l d e r s , I d i d n o t o b s e r v e m o o s e o r d e e r d o i n g s o . G e n e r a l l y d e e r a p p e a r t o b e m o r e n i m b l e a n d e l e g a n t w h e n s c r a t c h i n g w i t h t h e h i n d l e g o r n i b b l i n g t h e i r b o d y t h a n s h e e p . T h e g i r a f f e h a s e v o l v e d c o m f o r t m o v e m e n t s d i f f e r e n t f r o m t h o s e o f s h e e p , d e e r o r m o u n t a i n g o a t . I t d o e s s o m e r u b b i n g o n t a i l s h r u b s o r t r e e s ; i t d o e s n o t s c r a t c h i t s e l f w i t h t h e h i n d l e g s o r t h e h o r n s , i t s m a i n m e t h o d o f c l e a n i n g i t s b o d y s u r f a c e i s n i b b l i n g w i t h t h e i n c i s o r s a n d l i c k i n g o r s m a c k i n g t h e b o d y s u r f a c e w i t h i t s t o n g u e . I n a d d i t i o n , t h e t a i l i s u s e d f o r s w a t t i n g , a n d t h e s k i n c a n b e q u i v e r e d q u i c k l y p r e s u m a b l y t o d i s l o d g e i n s e c t p e s t s ( B a c k h a u s , 1 9 6 1 ) . T o d i s l o d g e i n s e c t p e s t s , m o u n t a i n s h e e p a n d c a r i b o u j e r k t h e i r h i n d l e g s , f l i p t h e e a r s a n d t a i l , w h i l e c a r i b o u m a y g a l l o p o n 3 3 t o l a r g e s n o w p a t c h e s o r p a r t i a l l y s u b m e r g e t h e m s e l v e s i n w a t e r . I t a p p e a r s t o m e t h a t c o m f o r t m o v e m e n t s a r e p r i m a r i l y a d j u s t e d t o t h e k i n d o f b o d y c o v e r i n g e v o l v e d b y t h e a n i m a l , u s i n g t h e m o s t a c c e s s i b l e m e a n s - b e i t t e e t h , h o r n s , t o n g u e o r h o o v e s - t o r u b a n d c l e a n s e t h e f u r ; i n s p e c i a l c a s e s , s u c h a s t h e l o n g w o o l y h a i r o f m o u n t a i n g o a t s c o m m o n c o m f o r t m o v e m e n t s a t r o p h i e d a n d w e r e r e p l a c e d b y a s p e c i a l i z e d b u t m o r e a p p r o p r i a t e b e h a v i o u r . R u m i n a n t s e v o l v i n g in c o m m o n h a b i t a t s w i l l p r o b a b l y e v o l v e s i m i l a r b o d y c o v e r s a n d s i m i l a r c o m f o r t m o v e m e n t s , a l t h o u g h s h e e p a n d m o u n t a i n g o a t d e m o n s t r a t e t h a t t h i s n e e d n o t o c c u r . F u r t h e r m o r e , s y m b i o n t s l i k e t i c k - b i r d s o f A f r i c a m a y a l s o d o c l e a n s i n g o f t h e b o d y s u r f a c e a s B a c k h a u s ( 1 9 6 1 ) p o i n t e d o u t , a n d s o m e h o w i n f l u e n c e t h e e v o l u t i o n o f c o m f o r t m o v e m e n t s . T h i s a l l i n d i c a t e s t h a t a c o m p a r i s o n o f c o m f o r t m o v e m e n t s b e t w e e n d i f f e r e n t s p e c i e s h a s l i t t l e m e r i t i f t h e b i o l o g y o f t h e s p e c i e s i s , n o t k n o w n . 3 4 S o c i a l b e h a v i o u r A t t e n t i o n , a l a r m , h o r n i n g a n d e l i m i n a t i n g b e h a v i o u r T h e m o s t c o m m o n p o s t u r e s a s s u m e d b y s h e e p a r e t h o s e o f g r a z i n g , r e s t i n g a n d w a l k i n g . N o n e o f t h e s e h a s s o c i a l m e a n i n g i n t h e s e n s e t h a t n o r e s p o n s e s t o t h e s e b e h a v i o u r s a r e n o t i c e a b l e f r o m o t h e r s h e e p . D u r i n g n o r m a l w a l k i n g , t h e s h e e p ' s h e a d i s h e l d q u i t e l o w , n o s e p o i n t i n g t o t h e g r o u n d w h i l e t h e e a r s a r e h e l d b a c k a n d d r o o p d o w n a l i t t l e . Y e t , o n e d e v i a t i o n f r o m t h i s p o s i t i o n , a s h a r p r a i s i n g o f t h e h e a d c o u p l e d w i t h a t e n s e w a l k o r a r i g i d l y h e l d b o d y a t o n c e d r a w s t h e a t t e n t i o n o f o t h e r s h e e p . I t i s t h e a l a r m p o s t u r e ( P i g . 2 5 ) ; e l k h a v e a n a l m o s t i d e n t i c a l a l a r m p o s t u r e ( P i g . 2 6 ) . A n a l a r m e d s h e e p n e e d n o t r u n a w a y , b u t m a y m o v e a t a s t i f f , t e n s e w a l k u p h i l l . I t s t o p s p e r i o d i c a l l y , l o o k s a t t h e s o u r c e o f d i s t u r b a n c e , a n d t h e n s t r u t s o n a g a i n . I t a p p e a r s t o g l a n c e a t t h e d i s t u r b a n c e f r o m t h e c o r n e r o f o n e e y e . O n s e v e r a l o c c a s i o n s s i n g l e r a m s c a r r i e d t h e a l a r m b e h a v i o u r t o e x t r e m e s . T h e y s t r u t t e d a b o u t i n t i g h t c i r c l e s i n o n e p l a c e , s t o p p i n g p e r i o d i c a l l y t o l o o k a t m e , a n d f i n a l l y s l o w l y l a y d o w n f a c i n g m e . M u r i e ( 1 9 4 4 ) d e s c r i b e d a w h o l e b a n d o f D a l l ' s s h e e p d o i n g t h i s i n f r o n t o f a w o l f . I n a d d i t i o n t o a s s u m i n g t h e c h a r a c t e r i s t i c p o s t u r e , a l a r m e d s h e e p m a y s t a m p t h e g r o u n d w i t h o n e f r o n t l e g ( b u t r a r e l y d o s o ) , a n d b l o w s h a r p l y t h r o u g h t h e n o s e . T h i s i s d o n e b y d o m e s t i c g o a t s ( C a p r a h i r c u s ) . a n d s o m e A s i a t i c s h e e p ( W a l t h e r , 1 9 6 1 ) . 3 5 A s h e e p s u d d e n l y f r e e z i n g a n d s t a r i n g i n o n e d i r e c t i o n , a l e r t s o t h e r s w h o t h e n d o l i k e w i s e . T h i s i s t h e a t t e n t i o n p o s t u r e ( F i g . 2 7 ) . T h e e a r s a r e p e r k e d f o r w a r d a n d t h e a n i m a l m a y o r i e n t i t s b o d y a l o n g t h e l i n e o f s i g h t . A s h e e p s t a n d i n g a n d l o o k i n g s t e a d i l y i n a t e n s e , r i g i d s t a n c e i n o n e d i r e c t i o n , h a s v e r y l i k e l y s e e n s o m e t h i n g o f i n t e r e s t s u c h a s a p r e d a t o r , o r a d i s t a n t s h e e p . A s h e e p w h i c h f r e q u e n t l y i n t e r r u p t s f e e d i n g a n d t h e n l o o k s s t e a d i l y a c r o s s a g o r g e , v a l l e y o r b e l t o f t i m b e r , a s s u m i n g a l e s s r i g i d p o s t u r e , i n d i c a t e s t h a t i t w i l l s o o n m o v e i n t h a t d i r e c t i o n . W i t h i t s g a z e t h e s h e e p g i v e s n o t i c e o f i t s i n t e n t , a n d t h e d i r e c t i o n i t w i l l t a k e . S c h a l l e r ( 1 9 6 3 ) a n d K u h m e ( 1 9 6 5 ) d e s c r i b e d s i m i l a r b e h a v i o u r o f l e a d e r s o f g o r i l l a a n d A f r i c a n h u n t i n g d o g ( L y c a o n ) g r o u p s , r e s p e c t i v e l y . N e i t h e r t h e d e f e c a t i n g n o r u r i n a t i n g p o s t u r e o f r a m s d e v i a t e s a p p r e c i a b l y f r o m t h e n o r m a l s t a n c e , a n d a p p e a r s t o c a r r y n o s o c i a l s i g n i f i c a n c e . H o w e v e r , t h e e w e d o e s u r i n a t e i n a m o s t c o n s p i c u o u s m a n n e r ( F i g . 2 3 ) a n d d r a w s t h e a t t e n t i o n o f n e a r b y r a m s . T h e y c o m e a n d n u z z l e t h e f e m a l e ' s v u l v a a n d u r i n e , a n d v e r y f r e q u e n t l y p e r f o r m a l i p c u r l t h e r e a f t e r ( F i g . 4 8 ) . W a l t h e r ( 1 9 5 8 ) s u g g e s t e d t h a t i n s p e c i e s i n w h i c h u r i n e o r d u n g p l a y e d a s o c i a l r o l e , t h e u r i n a t i o n o r d e f e c a t i o n p o s t u r e i s c o n s p i c u o u s . T h e a c t o f d e f e c a t i n g o r u r i n a t i n g i s s i g n a l l e d t h e r e b y t o c o n s p e c i f i c s . T h e r e s e e m s t o b e m e r i t t o W a l t h e r ' s s u g g e s t i o n ; t h e d e f e c a t i o n p o s t u r e o f c a t t l e i s 3 6 a c c e n t u a t e d a n d d e f e c a t i o n i s a c o n s i s t e n t p a r t o f p r e - c o m b a t b e h a v i o u r ( S c h l o e t h , 1 9 6 1 ) ; t h e c o n s p i c u o u s d e  f e c a t i o n p o s t u r e o f O r j r x b u l l s i s s h o w n b y t h e d o m i n a n t m a l e a f t e r c h a s i n g o f f s u b o r d i n a t e o n e s ( W a l t h e r , 1 9 5 8 ) . H o w e v e r , i t i s n o t k n o w n w h a t s e l e c t i v e f o r c e s f a v o u r c o n s p i c u o u s e l i m i n a t i o n b e h a v i o u r . H o r n i n g o f s h r u b s , g r a s s b u n c h e s o r s m a l l t r e e s m a y h a v e s o m e s o c i a l m e a n i n g ( F i g . 2 8 ) . I t o c c u r s f r e q u e n t l y d u r i n g d o m i n a n c e f i g h t s o f r a m s , a n d i s p e r f o r m e d e q u a l l y o f t e n b y t h e p a r t n e r s ( p . 7 8 F i g . 7 3 ) . S o m e o f t h e h o r n i n g m a y s i m p l y b e d o n e t o r e m o v e a n u n c o m f o r t a b l e c l u m p o r h a i r o r o t h e r i r r i t a n t f r o m b e t w e e n t h e h o r n s . O c c a s i o n a l l y , r a m s b u t t e d h e a v i l y a g a i n s t e l a s t i c c o n i f e r s t e m s a n d l e t t h e b a c k l a s h c a r r y t h e m b a c k t o t h e o r i g i n a l s t a n c e . O t h e r r a m s h o r n e d a n d n i b b l e d j u n i p e r b r a n c h e s ( J u n i p e r u s ) a l t e r n a  t i v e l y a n d a p p e a r e d t o g r o w m o r e e x c i t e d b y d o i n g i t . I t a p p e a r e d t h a t r a m s p r e f e r r e d l o d g e p o l e p i n e ( P i n u s c o n t o r t a ) f o r h o r n i n g , a n d t h e t w i s t e d , d a m a g e d s t e m s o f s m a l l p i n e s a t t i m b e r l i n e ( F i g . 2 9 ) g a v e a m p l e e v i d e n c e o f t h i s . W h i t e - t a i l d e e r ( O d o c o i l e u s v i r g i i i i a n u s ) a l s o p r e f e r c o n i f e r s f o r h o r n i n g ( d e V o s , p e r s o n a l c o m m . ) . I t m a y b e t h a t e s s e n t i a l o i l s f o u n d i n c o n i f e r s s t i m u l a t e s h e e p , d e e r a n d a l s o e l k t o d a m a g e t h e s e t r e e s . I o b s e r v e d o n e c o w - e l k t e a r o f f b a r k f r o m l p i n e s i n s a p , t h e n r u b h e r h e a d a n d n e c k l i b e r a l l y i n 3 7 t h e t r e e ' s w o u n d . E x p e r i m e n t s b y G u n d l a c h ( 1 9 6 1 ) o n r e d d e e r ( C e r v u s e l a p h u s ) s h o w e d t h e e x c i t a t o r y e f f e c t s o f p i n e o i l s o n t h e s e d e e r . G e n e r a l l y s h e e p h o r n d u r i n g i n t e n s e s o c i a l i n t e r  a c t i o n s , o r p r i o r t o l o n g , m o v e m e n t s t h r o u g h t i m b e r e d v a l l e y f l o o r s . M o u n t a i n g o a t s w e r e a l s o o b s e r v e d t o h o r n s h r u b s a n d g r a s s b u s h e s i n a g o n i s t i c i n t e r a c t i o n s . T h i s b e h a v i o u r i s o c c a s i o n a l l y c o n t a g i o u s , f o r s e v e r a l r a m s m a y s t a r t h o r n  i n g a f t e r o n e b e g i n s . H o r n i n g m a y b e i n i t i a t e d w i t h a b u t t , a f t e r w h i c h t h e h o r n s a r e r o t a t e d o r s c r u b b e d u n d e r p r e s s u r e o v e r t h e g r a s s b u n c h , s h r u b o r s m a l l t r e e . T h e h o r n i n g p o s t u r e i s o f t e n t e n s e a n d t h e t a i l m a y b e r a i s e d . T h e r e i s a n a g g r e s s i v e o v e r t o n e i n t h i s b e h a v i o u r . O r i e n t a t i o n t o w a r d s t h e c o n s p e c i f i c ; W h e n t h e e w e c a l l s h e r l a m b , s h e o r i e n t s h e r s e l f t o w a r d s t h e l a m b a n d l o o k s d i r e c t l y a t i t . I e m p h a s i z e t h i s , b e c a u s e f o r s h e e p a d i r e c t s t a r e a p p e a r s t o b e a n a g g r e s s i v e p a t t e r n a n d i s n o t t o l e r a t e d . T h e e v i d e n c e f o r t h i s i s i n d i r e c t . S u b o r d i n a t e s l o o k a w a y f r o m d o m i n a n t s w h e n t h e l a t t e r a p p r o a c h ( F i g s . 3 0 & 3 2 a ) a n d o f t e n t u r n t h e i r r e a r t o t h e m . E v e n l a m b s d o t h i s ( F i g . 3 1 ) . I n t h i s f i g u r e n o t e t h e i r o r i e n t a t i o n w h e n t h e y e a r l i n g f e m a l e w a s p r e s e n t a n d w h e n s h e d e p a r t e d . D u r i n g t h e p o s t - c l a s h 3 8 h o r n d i s p l a y t h e s u b o r d i n a t e r a m m a y c l o s e h i s e y e s r a t h e r t h a n l o o k a t t h e d o m i n a n t ' s f a c e ( F i g . 3 4 ) . S h e e p t e n d t o r e s t i n s u c h a m a n n e r a s n o t t o f a c e e a c h o t h e r d i r e c t l y ( F i g . 3 2 b ) . I t a p p e a r s t o m e t h a t l o o k i n g a t a c o n s p e c i f i c d i r e c t l y a t s h o r t r a n g e i s t h e p r e r o g a t i v e o f t h e l a r g e r s h e e p ( F i g . 3 2 a ) , a n d t h a t t h e s m a l l e r s h e e p w h i c h h a p p e n e d t o d o i t w e r e f r e q u e n t l y b u t t e d i n r e t u r n . G e n e r a l l y , w h e n s h e e p a r e c l o s e t o g e t h e r , t h e y f a c e i n t h e s a m e d i r e c  t i o n , p r o b a b l y b e c a u s e t h i s m i n i m i z e s s t a r i n g . W h e n s h e e p a r e o n t h e m o v e , t h e y d i s c o u r a g e o t h e r s f r o m p a s s i n g t h e m b y d i s p l a y i n g , b u t t i n g , c u t t i n g o f f t h e - o n e a t t e m p t i n g t o p a s s , o r r u n n i n g q u i c k l y a h e a d t h e r e b y r e s t o r i n g t h e o r i g i n a l p o s i t i o n . I t c a n b e o c c a s i o n a l l y o b s e r v e d h o w a s m a l l e r s h e e p , a t t e m p t i n g t o w a l k p a s t a d o m i  n a n t a t c l o s e r a n g e , i s b u t t e d a s s o o n a s i t r e a c h e s t h e s h o u l d e r l e v e l o f t h e l a t t e r . I t a p p e a r s t h a t d o m i n a n t s t r y t o k e e p o t h e r s b e h i n d t h e m . T h i s r e s u l t s i n a r e m a r k a b l y s t a b l e ; m a r c h o r d e r w h e n s h e e p a r e o n t h e m o v e , b u t a l s o g i v e s r i s e t o t h e i l l u s i o n t h a t t h e d o m i n a n t , l e a d i n g t h e s h e e p a t t e m p t s t o d e f e n d i t s " l e a d " p o s i t i o n . B e h a v i o u r p a t t e r n s e x c h a n g e d b e t w e e n c o n s p e c i f i e s : S u c h p a t t e r n s c a n b e d i v i d e d i n t o t h o s e w h i c h a r e s h o w n b y t h e e w e a n d h e r l a m b , a n d t h o s e w h i c h a d u l t s p e r f o r m t o w a r d s o n e a n o t h e r . O n l y t h e l a t t e r k i n d o f b e h a v i o u r p a t t e r n s w i l l b e c o n s i d e r e d h e r e . 3 9 T h e h o r n d i s p l a y s . T h e s e a r e t h e m o s t c o m m o n s o c i a l b e h a v i o u r p a t t e r n s o f s h e e p , p e r f o r m e d u s u a l l y b y d o m i n a n t t o w a r d s s u b o r d i n a t e i n d i v i d u a l s . D o m i n a n t h e r e a l w a y s m e a n s t h e a n i m a l a c t s i n a m a n n e r c h a r a c t e r i s t i c o f a l a r g e r b o d i e d s h e e p t o w a r d s a s m a l l e r o n e . T h e h o r n d i s  p l a y s a r e i n d i r e c t - o r p r e s e n t - t h r e a t s ( G e i s t , 1 9 6 4 ) , c o m p a r a b l e t o t h e b r o a d s i d e d i s p l a y s o f m a n y m a m m a l s . H o r n s a r e d i s p l a y e d f r o m t w o p o s t u r e s , t h e l o w - s t r e t c h a n d t h e p r e s e n t ( F i g s . 3 3 & 3 4 ) . T h e f o r m e r i s t h e m o r e c o n s p i c u o u s , a n d t h e o n l y h o r n d i s p l a y I q u a n t i f i e d . F r o m b o t h p o s t u r e s t h e h o r n s a r e s h o w n f r o n t o - l a t e r a l l y ( F i g . 3 5 ) . I t a p p e a r s t h a t w i t h t h i s o r i e n t a t i o n m o r e " h o r n " i s v i s i b l e t o t h e o p p o n e n t t h a n f r o m a f r o n t a l o r l a t e r a l p o s i t i o n . D u r i n g t h e a p p r o a c h i n l o w - s t r e t c h s h e e p m a y f l i c k e r t h e i r t o n g u e . T h e e a r s a r e d e f l e c t e d s i d e w a y s , o r t h e e a r o n t h e o f f - s i d e t o t h e o p p o n e n t i s h e l d s t r a i g h t o u t ( a l s o m u l e d e e r b u c k s , G e i s t 1 9 6 6 ; f o r b l a c k b u c k ( A n t i l o p e ) W a l t e r , 1 9 6 0 , d e s c r i b e d t h e o p p o s i t e ) : d u r i n g s o m e l o w - s t r e t c h a p p r o a c h e s t h e e a r s a r e p o i n t e d t o w a r d s t h e o p p o n e n t . T h e l o w - s t r e t c h o c c u r s d u r i n g t h e f o l l o w i n g s o c i a l i n t e r a c t i o n s : ( l ) B e t w e e n r a m s i n t h e i r f r e q u e n t e n g a g e m e n t s ( F i g . 3 7 ) . R a m s o f e q u a l h o r n s i z e t e n d t o d i s p l a y t o e a c h o t h e r ( w h e r e a s n o r m a l l y o n l y t h e l a r g e r h o r n e d r a m d i s p l a y s ) . 4 0 ( 2 ) B y r a m s ( a n d o c c a s i o n a l l y e w e s ) w h e n e n t e r i n g a b a n d , l e a v i n g a b a n d , p a s s i n g a s m a l l e r i n d i v i d u a l - o r a l a r g e r o n e a t l o n g e r d i s t a n c e - a n d o c c a  s i o n a l l y b y t h e r a m l e a d i n g a b a n d . ( 3 ) B y e w e s a n d r a m s a t t e m p t i n g t o d i s p l a c e a s u b o r d i  n a t e f r o m h i s r e s t i n g p l a c e ( P i g . 3 2 g ) a n d b y e w e s t o w a r d s s m a l l e r e w e s o r s u b a d u l t s . ( 4 ) B y r a m s t o w a r d s e w e s w h e n i n i t i a t i n g c o u r t s h i p . H e r e t h e r a m m a y c r o u c h s l i g h t l y a n d i n s o m e i n s t a n c e s g o v e r y l o w i n f r o n t ( F i g . 3 8 ) . ( 5 ) W h e n p a s s i n g a n o t h e r s p e c i e s , i . e . d e e r . T h i s I h a v e s e e n , h o w e v e r , o n o n e o c c a s i o n o n l y . T h e l o w - s t r e t c h i s s h o w n m o r e f r e q u e n t l y b y r a m s t h a n e w e s , m o r e b y o l d e r r a m s t h a n y o u n g e r a n i m a l s ; t h e e a r l i e s t a g e a t w h i c h s h e e p p e r f o r m t h e l o w - s t r e t c h a p p e a r s t o b e 5 - 6 m o n t h s . T h i s b e h a v i o u r i s a l m o s t a b s e n t f r o m t h e b e h a v i o u r o f l a m b s . T h e " p r e s e n t " i s p e r f o r m e d w i t h t h e h e a d h e l d h i g h a n d t h e n o s e p u l l e d s l i g h t l y a w a y f r o m t h e o p p o n e n t , s o t h a t d i s p l a y i n g r a m s a p p e a r t o l o o k p a s t e a c h o t h e r ( F i g . 3 4 ) . T h e e a r s a r e u s u a l l y f o l d e d b a c k , t h e e y e s o f t h e s u b o r d i n a t e r a m m a y b e s h u t . T h e p r e s e n t u s u a l l y f o l l o w s a c l a s h . T h e c a m s r e c o i l b a c k a n d f r e e z e i n t o t h e p r e s e n t . I t o c c u r s p r i m a r i l y a f t e r c l a s h e s o r t h r e a t j u m p s p e r f o r m e d i n d o m i n a n c e 4 1 f i g h t s a n d i s u s u a l l y m i s s i n g a f t e r c l a s h e s d u r i n g v i c i o u s b a t t l e s . T h e p r e s e n t i s c o m m o n l y s e e n d u r i n g h u d d l e s o f r a m s , a n d o c c u r s a l s o d u r i n g c o u r t s h i p o f t h e e s t r u s e w e ( F i g . 9 4 ) . T h e t w i s t ; T h e t w i s t c a n b e i n t e r p r e t e d a s a n i n  t e n s i f i e d h o r n d i s p l a y f r o m t h e l o w - s t r e t c h p o s i t i o n . T h e d i s p l a y i s i n t e n s i f i e d b y t h e a d d i t i o n o f a r a p i d r o t a t i o n o f t h e h e a d a b o u t i t s m e d i a n a x i s , i n t e n s i f i e d t o n g u e f l i c k e r i n g , a l o u d g r o w l , a n d o c c a s i o n a l l y a n u d g e i n t o t h e o p p o n e n t ' s s i d e w i t h t h e m u z z l e . A t w i s t m a y t e r m i n a t e a l o w - s t r e t c h a p p r o a c h a n d t h e r a m f r e e z e s i n t o a h o r n d i s p l a y ; t w i s t s m a y a l t e r n a t e w i t h l o w - s t r e t c h h o r n d i s p l a y s a s t h e r a m s t a n d s b e h i n d a n d d i s p l a y s t o a s m a l l e r s u b o r d i n a t e . D u r i n g c o u r t s h i p o f e w e s a b o u t t o e n t e r e s t r u s , y o u n g r a m s m a y p o u n c e f o r w a r d t o w a r d s t h e e w e , q u i c k l y l o w e r t h e h e a d a n d t w i s t w h i l e f l i c k e r i n g t h e t o n g u e a n d u t t e r i n g a g r o w l , t h e n r e t u r n t o a n e a r n o r m a l s t a n c e . T h i s r e p e a t s i t s e l f w i t h t h e r a m t w i s t i n g o n c e l e f t , o n c e r i g h t ( F i g . 4 0 ) . T h e r a m r e m a i n s c o n s t a n t l y s o m e d i s t a n c e f r o m t h e e w e . D u r i n g r a m e n g a g e m e n t s t h e d o m i n a n t m a y n o t o n l y n u d g e t h e s u b o r d i  n a t e d u r i n g t h e t w i s t a n d f l i c k e r t h e . t o n g u e i n h i s f u r , b u t s i m u l t a n e o u s l y p u s h h i m w i t h t h e c h e s t . 4 2 T h e f r o n t k i c k ( L a u f e i n s e h l a g , W a l t h e r , 1 9 5 8 ) : T h e k i c k w i t h t h e f r o n t l e g i s v e r y f r e q u e n t l y p e r f o r m e d r i g h t a f t e r t h e i n i t i a t i n g l o w - s t r e t c h o r t w i s t . I t i s a b e h a v i o u r u s e d m a i n l 3 r b y d o m i n a n t r a m s . T h e r a m r a i s e s a f r o n t l e g a n d h i t s t h e o p p o n e n t v e n t r a l l y o n b e l l y , c h e s t o r h a u n c h e s , r a r e l y o n n e c k o r c h i n ( F i g s . 4 1 & 4 2 ) . O c c a s i o n a l l y h e m a y t a k e t h e o p p o n e n t ' s b o d y i n a f r o n t l e g - c h i n p i n c e r . T h e t w i s t a n d f r o n t k i c k a r e f r e q u e n t l y c o m b i n e d ( F i g . 4 1 ) . R a m s m a y g r o w l l o u d l y w h e n k i c k i n g e s t r u s e w e s o r o t h e r r a m s d u r i n g i n t e n s e r a m - r a m i n t e r a c t i o n s . O c c a s i o n a l l y t h e y b u m p t h e i r c h e s t i n t o t h e o p p o n e n t ' s s i d e d u r i n g e a c h k i c k a n d - r a r e l y - d i g a h o r n t i p i n t o h i s b a c k . L a t t e r b e  h a v i o u r I s a w n o t i n f r e q u e n t l y a m o n g b i g h o r n s b u t o n l y d u r i n g o n e d o m i n a n c e f l i g h t a m o n g S t o n e ' s s h e e p . I h a v e a l s o s e e n l a r g e r a m s c o m b i n e t h e k i c k w i t h s u c h a s t r o n g p u s h w i t h t h e c h e s t , t h a t t h e y m o v e d t h e o p p o n e n t s e v e r a l s t e p s d o w n h i l l . I n e x t r e m e s i t u a t i o n s , i . e . b y r a m s a b o u t a n e s t r u s e w e , r a m s m a y k i c k s o h i g h u p o n a n o p p o n e n t ' s h a u n c h t h a t i t a p p e a r s t h e r a m a t t e m p t s t o m o u n t . T h e f r o n t k i c k i s l e s s a k i c k t h a n t a p p i n g . I h a v e e x p e r i e n c e d i t a b o u t a d o z e n t i m e s w h e n g e t t i n g b e t w e e n t w o i n t e r a c t i n g s h e e p . T h i s i s a l m o s t c o m p l e t e l y a b e h a v i o u r p a t t e r n o f r a m s , f o r e w e s p e r f o r m i t v e r y r a r e l y b u t i n t h e s a m e c o n t e x t a s r a m s ( F i g . 7 1 ) . O l d r a m s p e r f o r m i t m o r e 4 3 f r e q u e n t l y t h a n y o u n g ( F i g . 1 0 3 ) . V e r y r a r e l y , p a w i n g w i l l r e p l a c e t h e f r o n t k i c k i f t h e o p p o n e n t h a p p e n s t o h e r e s t i n g ( F i g . 1 7 ) . T h e f r o n t k i c k i s a c h a r a c t e r i s t i c b e h a v i o u r p a t t e r n o f m a n y , t h o u g h n o t a l l r u m i n a n t s . I t i s a b s e n t i n d e e r , b u t d o e s o c c u r i n b o t h l i v i n g s p e c i e s o f t h e G i r a f f i d a e ( W a l t h e r , 1 9 6 0 ) a n d m a n y , b u t n o t a l l , t r i b e s o f t h e B o v i d a e ( W a l t h e r , 1 9 6 0 ) . I n a l l s p e c i e s f o r w h i c h t h i s b e h a v i o u r p a t t e r n w a s d e s c r i b e d , i t i s p e r f o r m e d d u r i n g c o u r t s h i p b y t h e m a l e o n t h e f e m a l e , o f t e n i t i s h i g h l y r i t u a l i s e d a s , f o r i n s t a n c e , i n t h e g e i e n r u k ( L i t h o c r a n i u s ) ( W a l t h e r , 1 9 5 8 ) . M o u n t a i n s h e e p a p p e a r t o d i f f e r f r o m t h i s r u l e a s m a l e s p e r  f o r m f r o n t k i c k s o n o t h e r m a l e s d u r i n g a g o n i s t i c i n t e r a c t i o n s . I s h a l l d e m o n s t r a t e l a t e r t h a t r a m s r e a l l y d o n o t d e v i a t e f r o m t h e r u l e , a n d t h a t t h e f r o n t k i c k a m o n g s h e e p i s s t i l l a c o u r t s h i p p a t t e r n . S h e e p d i f f e r f r o m o t h e r k n o w n b o v . i d s i n  s o f a r a s t h e y d o n o t d i f f e r e n t i a t e b e h a v i o u r a l l y b e t w e e n m a l e a n d f e m a l e . A . b i g r a m t r e a t s e v e r y t h i n g s m a l l e r t h a n h e i s w i t h c o u r t s h i p p a t t e r n s i r r e s p e c t i v e o f s e x . I c a n n o t c o m  p l e t e l y a g r e e w i t h W a l t h e r ( 1 9 6 4 ) t h a t b e c a u s e t h e f r o n t k i c k a p p e a r s i n a g o n i s t i c s i t u a t i o n s b e t w e e n s h e e p , i t m u s t b e l o o k e d u p o n a s d e r i v e d f r o m a g g r e s s i v e b e h a v i o u r . I n A m e r i c a n s h e e p t h e f r o n t k i c k i s n o w p a r t o f t h e m a l e s p r e s e n t - t h r e a t c o m p l e x . 4 4 T h e n e c k f i g h t ( F i g . 4 3 ) : T h i s i s a v e r y r a r e b e h a v i o u r p a t t e r n o f r a m s w h i c h , i n t h e f e w i n s t a n c e s o b  s e r v e d , w a s p e r f o r m e d o n r a m s a s w e l l a s e w e s . T h e r a m p u t s h i s c h i n a n d t h r o a t o v e r t h e w i t h e r s o f h i s o p p o n e n t , h o w e v e r , n o w r e s t l i n g o r p u s h i n g f o l l o w s . T h i s b e h a v i o u r p a t t e r n , c o m m o n a n d f u n c t i o n a l i n t h e b a r b a r y s h e e p o r a o u d a d ( A m m o t r a g u s ) ( H a a s , 1 9 5 8 ) m u s t b e c o n s i d e r e d v e s t i g i a l f o r m o u n t a i n s h e e p . T h e m o u n t : M o u n t i n g i s p e r f o r m e d b y d o m i n a n t s o n s u b o r d i n a t e s o f b o t h s e x e s . E w e s m o u n t e a c h o t h e r r a r e l y . E x c e p t i o n a l l y a y o u n g r a m m a y m o u n t a l a r g e r , o l d e r r a m w h e n b o t h a r e p a r t o f a h u d d l e g r o u p . T h e m o u n t i n g p o s t u r e o f s h e e p i s q u i t e e r e c t , w i t h t h e n o s e f r e q u e n t l y p o i n t i n g a t t h e b a c k o f t h e p a r t n e r . P e l v i c s t r o k e s a r e p e r f o r m e d , i r r e s p e c t i v e o f t h e s e x o f t h e m o u n t e d . P r i o r t o m o u n t i n g , t h e p e n i s m a y b e p a r t i a l l y e x t r u d e d . I t w a s n o t e d e a r l i e r t h a t d o m i n a n t r a m s t r e a t s u b o r d i n a t e s a s i f t h e y w e r e f e m a l e s . I n a d d i t i o n , s u b o r d i n a t e s m a y r e a c t l i k e f e m a l e s t o t h e a c t i o n s o f t h e d o m i n a n t . T h u s t h e s m a l l r a m i n F i g . 4 4 m o u n t e d b y t h e l a r g e r o n e , p e r f o r m s l o r d o s i s . M o u n t i n g i s p a r t o f t h e d o m i n a n t - s u b o r d i n a t e b e h a v i o u r c o m p l e x , a n d h e n c e o c c u r s t h r o u g h o u t t h e y e a r . I t i s m o r e c o m m o n l y p e r f o r m e d b y y o u n g r a m s t h a n o l d o n e s w h e n c o u r t i n g n o n - e s t r u s e w e s ( F i g . 1 1 6 ) . L a m b s d u r i n g p l a y c o m m o n l y m o u n t e a c h o t h e r . 45 E j a c u l a t i o n : Rams may e j a c u l a t e t h r o u g h o u t the y e a r , d u r i n g i n t e r a c t i o n s w i t h o t h e r rams, w h i l e c o u r t i n g e s t r u s o r n o n - e s t r u s ewes; t h e y may e j a c u l a t e s p o n t a n e o u s l y w i t h o u t any v i s i b l e cause when a l o n e . T h i s happens o c c a  s i o n a l l y i n t h e m o r n i n g a f t e r t h e ram r i s e s f r om h i s b e d . E j a c u l a t i o n i s no t f r e q u e n t l y s e e n . D u r i n g t h e a c t t he ram s u d d e n t l y c r ouche s i n t h e r e a r , p r o t r u d e s t h e p e n i s s i deway s p a s t t h e f r o n t l e g s ( F i g . 45) t h e n s t a g g e r s s t i f f - l e g g e d ! y f o r w a r d o r s t e p s a r ound i n a na r r ow c i r c l e . When he w i t h  draws t h e p e n i s , t h e ram r e t u r n s f r om the s t i f f , t e n s e e j a c u  l a t i o n p o s t u r e t o t h e r e l a x e d no rma l s t a n c e . I saw a D a l l ram l i c k what was p r o b a b l y t h e e j a c u l a t e and p e r f o r m a l i p c u r l t h e r e a f t e r . U n l i k e t h e b a r b a r y sheep (Haas , 1958) or i b e x ( K r u m b i e g e l , 1952) moun ta i n sheep o n l y e x c e p t i o n a l l y n u z z l e t h e i r p e n i s d u r i n g e j a c u l a t i o n . ( I saw o n l y one s m a l l D a l l ram do s u ch . ) C o u r t s h i p : C o u r t s h i p i s p a r t o f t he dominant - s u b o r d i n a t e b e h a v i o u r o f sheep and c o n t a i n s most o f i t s b e  h a v i o u r p a t t e r n s . I s h a l l d e a l w i t h i t i n more d e t a i l l a t e r , b u t s h a l l d e s c r i b e h e r e some o f t h e b e h a v i o u r p a t t e r n s more u n i q u e t o c o u r t s h i p t h a n t o o t h e r i n t e r a c t i o n s . I n t h e most p r o b a b l e sequence, t h e ram approaches the ewe i n a l o w - s t r e t c h ( F i g . 4 6 ) , s n i f f s and l i c k s h e r v u l v a ( F i g . 4 7 ) , upon w h i c h t h e ewe u r i n a t e s and t h e ram - a f t e r n u z z l i n g t h e u r i n e - pe r f o r i n s a 1 i p c u r l ( F i g . 4 8 ) . Then the 4 6 r a m u s u a l l y l e a v e s t h e e w e . T h i s s e q u e n c e i s c o m m o n l y p e r f o r m e d o n n o n - e s t r u s e w e s . H o w e v e r , c o u r t s h i p i s m u c h m o r e v a r i e d t h a n i n d i c a t e d a b o v e . S e v e r a l r a m s m a y c o u r t o n e e w e ( F i g . 4 6 ) . T h e n o n - e s t r u s e w e m a y b e c o u r t e d b y s m a l l e r r a m s w i t h o u t t h e l a r g e r o n e s i n t e r f e r i n g ( F i g . 4 9 ) . L a r g e r r a m s d o n o t p r e v e n t s m a l l e r o n e s f r o m t e s t i n g a f e m a l e ' s u r i n e a n d o n e c o m m o n l y s e e s s e v e r a l r a m s l i p c u r l w h e r e o n e e w e u r i n a t e d ( F i g . 4 8 ) . S u b o r d i n a t e r a m s m a y u r i n a t e t o d o m i n a n t s a n d o c c a  s i o n a l l y a y e a r l i n g f e m a l e m a y u r i n a t e t o a d o m i n a n t e w e a p p r o a c h i n g h e r i n l o w - s t r e t c h . R a m s w i l l h e n c e l i p c u r l n o t o n l y o v e r t h e u r i n e o f e w e s , b u t a l s o o v e r t h e u r i n e o f o t h e r r a m s i n c l u d i n g t h e i r o w n . L i p c u r l i n g i s c o m m o n l y o b s e r v a b l e w h e n r a m s i n t e r a c t . I t i s p r o b a b l e t h a t l i p c u r l i n g i n d i c a t e s s e x u a l m a t u r i t y i n y e a r l i n g r a m s . T h o s e y e a r l i n g r a i n s w h i c h l i p c u r l e d d i d s h o w s o m e r u t t i n g b e h a v i o u r b u t n o t t h o s e t h a t d i d n o t l i p c u r l . L a m b a n d e w e s l i p c u r l s o r a r e l y t h a t I s a w o n l y o n e b i g h o r n e w e d o s o . T h e b e h a v i o u r p a t t e r n s d e s c r i b e d s o f a r a r e c h a r a c  t e r i s t i c o f l a r g e , d o m i n a n t s h e e p . T h e s o c i a l b e h a v i o u r p a t t e r n s f o l l o w i n g a r e m o r e c o m m o n l y i n i t i a t e d b y s u b o r d i n a t e s , w h i l e s o m e a r e e q u a l l y f r e q u e n t i n t h e b e h a v i o u r a l r e p e r t o i r e o f b o t h . 4 7 T h e h o r n t h r e a t : T h e h o r n t h r e a t i s a n i n d i c a t i o n m o v e m e n t t o b u t t a n d a s s u c h b e l o n g s t o t h e c a t e g o r y o f w e a p o n t h r e a t s ( G e i s t , 1 9 6 4 ) . I t i s f r e q u e n t l y s h o x m b y s u b o r d i n a t e s t o w a r d s a p p r o a c h i n g d o m i n a n t s , o r b y d o m i n a n t s c h a s i n g a w a y o r c h a r g i n g a t a s u b o r d i n a t e . T h e b e h a v i o u r c o n s i s t s o f l o w e r i n g t h e h e a d a n d i n c l i n i n g t h e h o r n s t o w a r d s t h e o p p o n e n t ( F i g . 3 3 ) . H o r n i n g , r u b b i n g , n u z z l i n g ( c o n t a c t p a t t e r n s ) : T h e s e a r e t h e m o s t c o m m o n l y u s e d b e h a v i o u r p a t t e r n s o f s m a l l r a m s o n l a r g e r o n e s . A f t e r a s m a l l r a m i n i t i a t e s a n a p p r o a c h h e b e g i n s t o l i c k a n d n u z z l e t h e h e a d o f t h e d o m i n a n t , t o h o r n h i s f a c e , n e c k , c h e s t o r s h o u l d e r s , o r t o r u b h i s f a c e o n t h e f a c e o f t h e d o m i n a n t ( F i g . 5 0 ) . O l d e r D a l l a s r a m s c a r r i e d d i s t i n c t g r e y a n d b l a c k m a r k i n g s a r o u n d t h e i r p r e o r b i t a l g l a n d s a n d e y e s , w h e r e a s s m a l l h o r n e d y o u n g r a m s s h o w e d l i t t l e e v i d e n c e o f t h i s ( F i g . 2 ) . I b e l i e v e t h e s e d i r t m a r k i n g s a r e c a u s e d b y t h e h o r n i n g o f y o u n g r a i n s . D u r i n g t h e f r e q u e n t d a i l y h o r n i n g s , d i r t a n d t h e s e c r e t i o n f r o m t h e p r e o r b i t a l g l a n d w o u l d b e s p r e a d a b o u t t h e e y e s o f l a r g e r a m s . I t i s m o s t l i k e l y , f u r t h e r m o r e , t h a t s u b o r d i n a t e r a m s w o u l d i m p r e g n a t e t h e i r o w n h o r n s a n d f a c e s w i t h t h e g l a n d ' s s e c r e t i o n . T h e r e f o r e , a b a n d o f r a m s w o u l d q u i t e l i k e l y a c q u i r e a g r o u p - s c e n t f r o m t h i s h o r n i n g . A t p r e s e n t t h e f u n c t i o n o f t h e p r e o r b i t a l g l a n d i s u n k n o w n . 4 8 I n o t e d e a r l i e r t h a t m o u n t a i n s h e e p h a i r i s v e r y b r i t t l e . T h i s d o e s n o t a p p l y t o t h e f a c i a l h a i r o f r a m s w h i c h i s q u i t e t o u g h . I t a p p e a r s t o m e t h a t t h i s m a y b e r e l a t e d t o t h e f a c i a l h o r n i n g s r a m s r e c e i v e a l m o s t d a i l y t h r o u g h o u t t h e y e a r . I f t h e f a c i a l h a i r w e r e b r i t t l e i t w o u l d b e q u i c k l y b r o k e n o f f a n d r e m o v e d b y t h e a c t i v i t y o f t h e s m a l l e r r a m s . R e m o v a l o f f a c i a l h a i r w o u l d e x p o s e t h e s k i n a n d l e a v e i t u n p r o t e c t e d d u r i n g c l a s h e s a n d d i r e c t l y e x p o s e d t o s n o w a n d c o l d t e m p e r a t u r e s i n w i n t e r . A p p a r e n t l y a s m a l l a i r s p a c e i s a d v a n t a g e o u s b e t w e e n s n o w a n d s k i n , f o r c a r i b o u , a m o n g t h e c o l d c l i m a t e g r a z e r s , h a v e c o m p l e t e l y f u r r e d m u z z l e s . I s u g g e s t t h a t r a m s w i t h s o f t , b r i t t l e f a c i a l h a i r w o u l d b e s e l e c t e d a g a i n s t . W h i l e a s u b o r d i n a t e i s l i c k i n g , h o r n i n g o r r u b b i n g t h e h e a d o r n e c k o f a d o m i n a n t , t h e l a t t e r s t a n d s a n d d i s  p l a y s i n p r e s e n t , a n d o c c a s i o n a l l y k i c k s a n d g r o w l s a t t h e s u b o r d i n a t e . T h e s e b e h a v i o u r p a t t e r n s , h o r n i n g , l i c k i n g a n d r u b b i n g a r e a l s o u s e d b y t h e c o u r t i n g e s t r u s e w e ( F i g . 9 4 ) . T h e b u t t : H o r n i n g b y t h e s u b o r d i n a t e m a y o c c a s i o n a l l y l e a d d i r e c t l y t o b u t t i n g . T h i s b e h a v i o u r p a t t e r n i s u s e d b y d o m i n a n t s a n d s u b o r d i n a t e s a b o u t e q u a l l y f r e q u e n t l y a n d i s t h e m i l d e s t , o v e r t a g g r e s s i v e . " p a t t e r n o f s h e e p ( F i g . 5 1 ) . 4 9 I t o c c u r s i n t h e h o r n t h r e a t - r u s h - b u t t s e q u e n c e ( F i g . 5 2 ) , w i t h w h i c h d o m i n a n t s c h a s e a w a y s u b o r d i n a t e s , a s e q u e n c e u s e d r e l a t i v e l y m o r e f r e q u e n t l y b y e w e s a n d s u b a d u l t s t h a n r a m s . D o m i n a n t r a m s t e n d t o b u t t s u b o r d i n a t e s w h i c h p a s s t o o c l o s e l y i n a l o w - s t r e t c h , a n d s u b o r d i n a t e s m a y b u t t d o m i n a n t s w h i c h c o m e t o t h e m i n a h o r n d i s p l a y . B i g h o r n r a m s o c c a s i o n a l l y c o m b i n e t h e f r o n t k i c k w i t h a b u t t o n s m a l l e r r a m s . T h e b u t t i s a n a t t e m p t t o h i t t h e o p p o n e n t w i t h t h e h o r n s . I t i s a h a m m e r - l i k e d o w n w a r d b l o w w i t h t h e h e a d d u r i n g w h i c h t h e c h i n i s d r a w n i n a n d t h e h o r n s t i l t e d o u t . A f t e r c o n t a c t i s m a d e w i t h t h e o p p o n e n t , t h e c h i n i s d r a w n i n e v e n t i g h t e r a n d t h e h o r n s p u s h e d i n t o h i s b o d y . T h e m o s t e x a g g e r a t e d f o r m o f t h e b u t t i s t h e c l a s h . T h e c l a s h : T h e c l a s h d i f f e r s f r o m t h e b u t t m a i n l y i n t h e f o r c e o f e x e c u t i o n a n d t h e m e a n s o f a c h i e v i n g t h i s . W h e r e a s t h e b u t t i s p e r f o r m e d b y o n e o p p o n e n t o n l y , b o t h o p p o n e n t s p a r t i c i p a t e i n t h e c l a s h . T h e c l a s h m a y b e d e l i v e r e d f r o m a f o u r l e g g e d s t a n c e o r a b i p e d a l r u n . M o v i e f i l m r e v e a l e d t h a t t h e c l a s h i s n o t s i m p l y t w o r a m s r u n n i n g h e a d l o n g i n t o e a c h o t h e r . I t c a n b e d i v i d e d i n t o s e v e r a l s t a g e s . T h e p r e p a r a t o r y s t a g e : T h e r a m i n i t i a t i n g t h e c l a s h f a c e s h i s o p p o n e n t , s i m u l t a n e o u s l y l i f t s o n e f r o n t l e g o f f t h e g r o u n d , c r o u c h e s i n t h e r e a r a n d t i l t s h i s h e a d s i d e w a y s . I f 5 0 t h e h e a d i s t i l t e d l e f t , i t w i l l h e t h e l e f t h o r n w h i c h w i l l f i r s t m a k e c o n t a c t w i t h t h e o p p o n e n t . T h e e y e s a r e w i d e o p e n a n d t h e e a r s a r e l a i d h a c k f l a t . T h e r a m m a y f u r t h e r g e t u p o n h i s h i n d l e g s a n d l i f t t h e f r o n t l e g s o f f t h e g r o u n d ( s e e t h r e a t - j u m p ) ( P i g . 5 3 ) . T h e f o r w a r d p r o p u l s i o n : T h e h i n d l e g s p r o p e l t h e b o d y u p a n d f o r w a r d , t h e e y e s a r e f i x e d o n t h e o p p o n e n t . N o w s e v e r a l c h a n g e s t a k e p l a c e : ( a ) T h e b o d y s t r a i g h t e n s o u t a n d b e g i n s t o d e s c e n d , ( b ) N e c k a n d h e a d a r e m o v e d d o w n a t a g r e a t e r r a t e t h a n t h e b o d y , ( c ) T h e c h i n i s p u l l e d i n s h a r p l y p r o p e l l i n g t h e h e a v y h o r n s f o r w a r d a n d d o w n w a r d . H e n c e , t h e r e a r e f o u r f o r c e s w h i c h i n c r e a s e t h e f o r w a r d a n d d o w n w a r d m o m e n t u m , ( l ) t h e b o d y p r o p u l s i o n , ( 2 ) t h e f a l l o f t h e b o d y d u e t o g r a v i t y , ( 3 ) t h e d o w n w a r d p r o p u l s i o n o f t h e n e c k a n d h e a d , a n d ( 4 ) t h e f o r w a r d a n d d o w n w a r d p r o p u l s i o n o f t h e h o r n s . I t a p p e a r s t h a t t h e s e f o r c e s w o u l d s u m m a t e , p r o d u c i n g a f a r h a r s h e r b l o w t h a n i f t h e r a m c l a s h e d r i g i d l y i n t o t h e o p p o n e n t ( P i g . 5 4 ) . C o n t a c t : J u s t p r i o r t o c o n t a c t t h e e y e s o f t h e r a m c l o s e . O n c o n t a c t w i t h o n e h o r n e d g e , t h e h e a d o f t h e r a m b e g i n s t o r o t a t e s o t h a t t h e n o s e p o i n t s d o w n . T h i s b r i n g s t h e s e c o n d h o r n i n t o c o n t a c t w i t h t h e o p p o n e n t . I t a p p e a r s 5 1 t h a t t h e c l a s h i s h e n c e a d o u b l e b l o w w i t h t h e h o r n s ( F i g . 5 5 ) . N o w t h e c l a s h m a y c o n t i n u e i n o n e o f t w o f a s h i o n s : ( a ) T h e s h e e p k i c k s u p i n t h e r e a r a n d p i v o t s i t s b o d y w e i g h t a b o u t t h e f r o n t l e g s , t h e r e b y " r i d i n g h o m e " t h e c l a s h . T h e u p w a r d t h r o w o f t h e r e a r -. i n c o m b i n a t i o n w i t h a r i g i d b o d y - w o u l d i n c r e a s e t h e d o w n w a r d f o r c e o f t h e h e a d ( F i g . 6 5 b & 5 6 ) . ( b ) T h e a n i m a l o n c o n t a c t c o l l a p s e s i t s f r o n t l e g s , l e t t i n g t h e r i g i d b o d y p i v o t i n t h e a c e t a b u l u m , a n d t h e n q u i c k l y c r o u c h e s i n t h e r e a r . B o t h t h e s e a c t i o n s w o u l d c o n  t i n u e t h e d o w n w a r d f o r c e b e h i n d t h e b l o w a f t e r c o n t a c t ( F i g . 6 7 ) . T h e c a t c h - p h a s e : A f t e r c o n t a c t t h e r a m b e g i n s t o p r e p a r e h i s b o d y f o r l a n d i n g ( F i g . 5 5 b ) . T h i s c o n s i s t s m a i n l y o f b r i n g i n g t h e l e g s i n t o l i n e w i t h h i s d e s c e n t ; i t i s b e s t i l l u s t r a t e d w h e n a c l a s h m i s s e s ( F i g . 5 8 ) . T h e r e a r e m a n y v a r i a t i o n s t o t h e c l a s h . I t m a y o c c u r w h e n t h e r a m ' s f r o n t l e g s a r e o f f t h e g r o u n d ( F i g . 5 9 ) , o r t h e h i n d l e g s a r e o f f t h e g r o u n d ( F i g . 3 , G e i s t , 1 9 6 6 c ) . T h e r a m m a y n o t c a t c h h i m s e l f w i t h h i s f r o n t l e g s a n d t h u s c r a s h h e a d f i r s t i n t o t h e g r o u n d ( F i g . 6 0 ) . T h e c l a s h i s f o l l o w e d d u r i n g d o m i n a n c e f i g h t s b y a p r e s e n t ( F i g . 3 4 ) . P r i m a r y e f f e c t s o f t h e c l a s h : B o t h t h e g r e a t f o r c e a n d t h e r o u g h , g r o o v e d h o r n s l e a v e t h e i r m a r k o n t h e o p p o n e n t . 5 2 T h e r i d g e s a n d g r o o v e s o f t h e h o r n s p e r m i t a g r i p o n t h e o p p o n e n t ' s b o d y , b u t t e a r o u t h a i r s i n t h e p r o c e s s . T h e h o r n s u r f a c e s o f f i g h t i n g r a m s a r e u s u a l l y c o v e r e d w i t h b i t s o f b r o k e n h a i r . T h e f o l l o w i n g e f f e c t s a r e n o t i c e a b l e : ( 1 ) S m a l l e r r a m s m a y g e t l i t e r a l l y t e l e s c o p e d b y t h e f o r c e ( F i g . 6 1 ) . H o w e v e r , I h a v e n o t s e e n r a m s t h r o w n b a c k b y a c l a s h , p r o b a b l y b e c a u s e m o s t c l a s h e s a r e i n i t i a t e d b y t h e s m a l l e r , s u b o r d i n a t e a n i m a l . ( 2 ) T h e n o s e a n d o r b i t a l r e g i o n s g e t b a d l y c u t ( F i g . 6 2 ) . ( 3 ) T h e h o r n t i p s g e t b r o k e n a n d s p l i n t e r e d , w h i l e c h u n k s g e t k n o c k e d o u t o f t h e h o r n e d g e s ( F i g . 6 2 ) . O c c a  s i o n a l l y , a l a r g e p a r t o f t h e h o r n i s l o s t ( F i g . 6 3 ) . ( 4 ) G a s h e s a r e o p e n e d 011 t h e b o d y w i t h b r o k e n h o r n t i p s ; o n e r a m a p p a r e n t l y r e c e i v e d a b r o k e n s h o u l d e r t h r o u g h a f i g h t ; o n e d e a d r a m f o u n d h a d t h e l e f t h o r n c o r e s n a p p e d o f f . C o n s i d e r a b l e a m o u n t o f b l o o d h a d a c c u m u l a t e d s u b - c u t a n e o u s l y , a s w a s i n d i c a t e d b y t h e d a r k r e d c o n n e c t i v e t i s s u e o n t h e l e f t s i d e o f t h e s k u l l . T h i s r a m w a s p r o b a b l y a f i g h t i n g c a s u a l t y . ( 5 ) H a i r i s t o r n o u t , o c c a s i o n a l l y i n g r e a t c l u m p s ( F i g . 6 2 ) . ( 6 ) B l o o d m a y b e f o u n d o n t h e h o r n s o f r a m s a f t e r t h e y . f i g h t . W h e n h o r n s a r e g r o w i n g i n s p r i n g a n d s u m m e r , 5 3 b l o o d o o z e s i n l a r g e d r o p s f r o m t h e c o n t a c t l i n e b e t w e e n h o r n s a n d f a c i a l s k i n . I d o n o t k n o w w h a t i n t e r n a l d a m a g e s , i f a n y , r a m s r e d e i v e d u r i n g f i g h t i n g . I h a v e n o t b e e n f o r t u n a t e e n o u g h t o a u t o p s y a r a m t h a t , h a d f o u g h t . T h e d a m a g e w h i c h w a s o b s e r v a b l e c e n t e r e d a b o u t t h e h e a d p r i m a r i l y , w h i c h i s n o t s u r p r i s i n g i f t h e d e f e n s i v e m e c h a n i s m s o f s h e e p a r e c o n  s i d e r e d . A s e c o n d a r y e f f e c t o f t h e c l a s h : I n a n e a r l i e r p a p e r I r e p o r t e d t h a t r a m s c a n j u d g e b y t h e h o r n s i z e o f a s t r a n g e r w h e t h e r h e i s d o m i n a n t o r s u b o r d i n a t e . L a r g e h o r n e d s t r a n g e r s a r e a c c e p t e d a s d o m i n a n t a n d s m a l l h o r n e d s t r a n g e r s a s s u b o r d i n a t e . D o m i n a n c e f i g h t s o c c u r b e t w e e n s t r a n g e r a m s o f e q u a l h o r n s i z e ( G e i s t 1 9 6 6 c ) . I t a p p e a r s t h e r e f o r e t h a t r a m s k n o w n o t o n l y t h e h o r n s i z e o f o t h e r r a m s , b u t a l s o t h e i r o w n . H o w i s t h i s p o s s i b l e ? R a m s u s u a l l y d i s p l a y t h e i r h o r n s i n a p r e s e n t i m m e d i a t e l y a f t e r a c l a s h . T h e y h e n c e e x p e r i e n c e b o t h t h e f o r c e o f t h e c l a s h a n d t h e s i g h t o f t h e o p p o n e n t ' s h o r n s . I t w a s n o t e d t h a t t h e c l a s h h a d f o u r f o r c e c o m p o n e n t s , o f w h i c h t h e l a s t o n e i s t h e d o w n w a r d b l o w w i t h t h e h o r n s . T h i s b l o w s h o u l d v a r y i n s e v e r i t y w i t h h o r n m a s s . A l a r g e h o r n e d r a m s h o u l d h e n c e d e a l o u t a m o r e s e v e r e h e a d b l o w t h a n a s m a l l h o r n e d r a m . T h i s b l o w i s f o l l o w e d a t o n c e b y t h e h o r n 5 4 d i s p l a y . H e n c e e a c h o p p o n e n t e x p e r i e n c e s a g i v e n b l o w f o r c e a n d s e e s t h e h o r n s o f t h e o p p o n e n t i m m e d i a t e l y a f t e r t h i s . T h e r a m s s h o u l d t h e n c o n n e c t t h e s t r e n g t h o f " b l o w s w i t h t h e h o r n s i z e o f o p p o n e n t s . T h e r e f o r e r a m s s h o u l d h e a b l e t o e s t i m a t e w h a t b l o w s t h e i r o p p o n e n t s a r e c a p a b l e o f p u r e l y b y l o o k i n g a t t h e i r h o r n s . S i n c e c l a s h i n g o c c u r s q u i t e f r e  q u e n t l y , r a m s a r e c o n s t a n t l y r e m i n d e d o f t h e r e l a t i o n s h i p b e t w e e n h o r n s i z e a n d t h e f o r c e o f b l o w s . H e n c e r a m s s h o u l d b e a b l e t o e s t i m a t e t h e c l a s h p o t e n t i a l o f s t r a n g e r s p u r e l y f r o m t h e i r h o r n s i z e . T h e d e f e n s e m e c h a n i s m s : T h e s i m p l e s t w a y t o e s c a p e t h e e f f e c t o f a c l a s h o r a b u t t i s t o j u m p a s i d e ( F i g . 5 8 ) , a b e h a v i o u r c o m m o n l y r e s o r t e d t o b y s u b a d u l t s a n d f e m a l e s b u t r a r e l y b y r a m s . O b s e r v a t i o n s i n t h e f i e l d a n d o f s l o w e d d o w n m o t i o n p i c t u r e f i l m o f f i g h t i n g s h e e p , s h o w e d t h a t t h e y c o n  s t a n t l y a t t e m p t e d t o f a c e t h e o p p o n e n t a n d c a t c h h i s b l o w s w i t h t h e i r h o r n s . I n F i g . 6 4 a 2 y e a r o l d r a m i s i n t h e p r o c e s s o f b u t t i n g a e w e . N o t e t h a t t h e e w e i s s w i n g i n g h e r b o d y a r o u n d t o l i n e u p w i t h t h e d i r e c t i o n o f t h e b u t t . H e r h e a d i s l o w e r e d a n d t h e h o r n s a r e p o i n t e d f o r w a r d t o r e c e i v e t h e b l o w . T h e d o w n w a r d b l o w w o u l d b e c a u g h t b y t h e h o r n s a g a i n s t t h e t e n s i o n o f t h e n e c k a n d w o u l d f o r c e t h e h e a d o f t h e e w e d o w n , b u t w o u l d h a r d l y d o a n y d a m a g e . O n e f u n c t i o n o f t h e h o r n s i s h e n c e t o s h i e l d t h e a n i m a l a n d n e u t r a l i z e t h e o p p o n e n t ' s b l o w s . T h i s p r o p o s e d f u n c t i o n e x p l a i n s m u c h o f 5 5 t h e s h e e p ' s h e a d m o r p h o l o g y . T h e f i r s t l i n e o f d e f e n s e a g a i n s t b l o w s o n t h e f a c e , i s a t h i c k t o u g h h i d e . I n f a c t , t h e s k i n o n t h e n o s e a n d f r o n t i s t h i c k e r t h a n o n a n y o t h e r p a r t o f t h e b o d y . U n  f o r t u n a t e l y I h a d o n l y o n e s p e c i m e n , a 6 ^ y e a r o l d S t o n e ' s r a m , t o e x a m i n e . T h e r e f o r e , I m a d e s k i n m e a s u r e m e n t s o n m a l e s o f d o m e s t i c g o a t s . T h e d o m e s t i c g o a t i s a c l o s e r e l a t i v e o f t h e s h e e p a n d p o s s e s s e s s i m i l a r f i g h t i n g b e h a v i o u r . T h e r e f o r e , t h e y s h o u l d h a v e s i m i l a r d e f e n s i v e m e c h a n i s m s , w h i c h i s b o r n e o u t b y b o t h s k J L n m e a s u r e m e n t s a n d s k u l l s t r u c  t u r e . F o r c o m p a r i s o n p u r p o s e s , t h e s k i n m e a s u r e m e n t s o f a m o u n t a i n g o a t m a l e a r e c o m p a r e d w i t h t h a t o f d o m e s t i c g o a t a n d S t o n e ' s s h e e p ( F i g . 6 5 ) . T h e m o u n t a i n g o a t d o e s n o t f i g h t l i k e t h e s h e e p o r d o m e s t i c g o a t w i t h f r o n t a l b u t t s , b u t s t r i k e s v e n t r a l l y a t t h e o p p o n e n t ' s b e l l y a n d h a u n c h e s . M o s t b l o w s e x c h a n g e d b y , . m o u n t a i n g o a t s l a n d o n r u m p a n d b e l l y , s i n c e t h e a n t a g o n i s t s a r e p o s i t i o n e d a n t i - p a r a l l e l t o e a c h o t h e r ( G e i s t , i n p r e s s ) . N o t e t h a t t h e g o a t h a s a " r u m p s h i e l d " o f t h i c k d e r m i s , w h i c h i n a 9 y e a r o l d m a l e r e a c h e d 22 mm i n t h i c k n e s s . O n t h e o t h e r h a n d t h e f a c i a l s k i n o f g o a t s i s t h i n , w h i c h c o r r e l a t e s w i t h t h e a b s e n c e o f h e a d - t o - h e a d f i g h t i n g i n t h i s s p e c i e s . I t a p p e a r s h e n c e , t h a t s p e c i e s d e v e l o p t h i c k s k i n w h e r e m o s t b l o w s t e n d t o l a n d d u r i n g f i g h t i n g . 5 6 T h e s k u l l s t r u c t u r e o f m o u n t a i n s h e e p , r a m s i n p a r t i c u l a r , a p p e a r s t o h e a d a p t e d t o w i t h s t a n d h e a v y c o n - c u s s i o n . L i k e o t h e r r u m i n a n t s , o r s w i n e , w h i c h c o l l i d e h e a d o n i n f i g h t i n g , t h e s k u l l o f s h e e p i s h e a v i l y p n e u m a t e d . T h e r e a r e t x r o l a y e r s o f h o n e , u p t o 5 c m a p a r t , o v e r l y i n g t h e b r a i n . I n t h e s p a c e b e t w e e n t h e s e b o n e s a r e n u m e r o u s c r o s s c o n n e c t i o n s o f b o n e , a c t i n g l i k e s t r u t s . T h e d o u b l e r o o f e x t e n d s f r o m a b o u t 5 - 6 c m b e f o r e t h e b r a i n t o t h e o c c i p u t . H e r e i t f u s e s i n t o o n e 2 c m t h i c k s p o n g y t e x t u r e d b o n e . T h e b o n y h o r n c o r e s , a b o u t 1 0 - 1 1 c m i n d i a m e t e r a t t h e b a s e , a r e f o r m e d f r o m t h e u p p e r s k u l l r o o f . T h e y a r e h o l l o w a n d f i l l e d w i t h a m a z e o f c r o s s c o n n e c t i o n s . S o m e o f t h e s e b o n y s t r u t s r a d i a t e o u t f r o m t h e l o w e r b o n y c a s e e n - c a p s u l i n g t h e b r a i n , a n d r u n a l m o s t h a l f o f t h e l e n g t h o f t h e h o r n c o r e . T h e b o n e f o r m i n g t h e h o r n c o r e i s v e r y d e n s e a n d u p t o 6 mm t h i c k . T h e n a s a l s a r e s o l i d l y f u s e d t o t h e f r o n t a l s a n d a r e o f d e n s e , s t r o n g b o n e . B y c o n t r a s t , t h e s k u l l o f m o u n t a i n g o a t i s l i g h t . T h e b r a i n i s e n c a p s u l e d i n o n e l a y e r o f l i g h t , s p o n g y t e x t u r e d b o n e . T h e n a s a l s a n d f r o n t a l s a r e b o t h t h i n . T h e w h o l e s k u l l i s f r a g i l e a n d f r a c t u r e s n o w a n d a g a i n o n g o a t s s h o t a n d w h o s u b s e q u e n t l y f a l l d o w n m o u n t a i n s i d e s . 57 T h e s p a c e s u r r o u n d i n g t h e l o w e r b r a i n c a s e o f s h e e p , a p p e a r s t o b e d e r i v e d f r o m t h e f r o n t a l s i n u s e s . I n m o u n  t a i n g o a t s t h e s e s i n u s e s a r e v e r y s m a l l a n d l o c a t e d j u s t a n t e r i o r t o t h e b r a i n o v e r t h e c r i b r i f o r m p l a t e . D o m e s t i c g o a t o c c u p y a p o s i t i o n i n t e r m e d i a t e b e t w e e n m o u n t a i n g o a t s a n d s h e e p . T h e s i n u s e s a r e g r e a t l y e n l a r g e d , b u t d o n o t r e a c h p a s t t h e h o r n c o r e s . H e n c e t h e p a r i e t a l s a r e o n e s p o n g y t e x t u r e d b o n e o v e r t h e b r a i n ; i n m o u n t a i n s h e e p t h e p a r i e t a l s a r e s p l i t i n t o a n u p p e r a n d l o w e r l a y e r c o n n e c t e d b y c r o s s s t r u t s . T h e s k u l l o f m a l e d o m e s t i c g o a t s i s m u c h h e a v i e r a n d s t u r d i e r t h a n t h a t o f m o u n t a i n g o a t s b u t i s n o t a s h e a v y , c o m p l e x a n d p r o b a b l y s t u r d y , a s t h a t o f b i g h o r n s h e e p . I t i s m o s t l i k e l y t h a t t h e r e a r e o t h e r a l t e r a t i o n s i n t h e s k u l l a n d t h e p l a c e m e n t a n d a t t a c h m e n t o f t h e b r a i n , o r t h e j u n c t i o n o f o c c i p u t t o t h e c e r v i c a l v e r t e b r a e . F o r t h e p r e s e n t t h e y e s c a p e d d e t e c t i o n . T h e r e i s , h o w e v e r , l i t t l e d o u b t t h a t t h e h a i r , s k i n a n d s k u l l s t r u c t u r e o f s h e e p h a s e v o l v e d u n d e r s e v e r e s o c i a l s e l e c t i o n . B e s i d e s s h o w i n g a d a p t a t i o n s t o t h e h a b i t a t , s u c h a s s u b h y p s o d o n t d e n t i t i o n o r w i d e i n t e r o c c u l a r d i s t a n c e ( u s e f u l f o r j u d g i n g d i s t a n c e w h e n j u m p i n g ) , t h e y a r e a l s o a d a p t e d t o t h e s o c i a l e n v i r o n m e n t o f s h e e p . T h e t h r e a t - j u m p : T h i s p a t t e r n i s a n i n t e n t i o n m o v e  m e n t t o c l a s h a n d i s h e n c e a w e a p o n - t h r e a t ( F i g . 8 6 ) . L i k e t h e c l a s h i t i s p r i m a r i l y a p a t t e r n i n i t i a t e d b y s m a l l e r s h e e p 5 8 a n d s h o w n t o l a r g e r o n e s . I t i s s h o w n h y b o t h s e x e s a n d h y l a m b s ( F i g . 5 3 ) . I t o c c u r s c o m m o n l y i n t h e p l a y o f s h e e p ( F i g s . 8 2 & 8 1 ) . D u r i n g d o m i n a n c e f i g h t s , s o m e t h r e a t j u m p s a r e f o l l o w e d a t o n c e b y t h e p r e s e n t ( h o r n d i s p l a y ) . T h e h e a d s h a k e : T h i s i s a b e h a v i o u r s h o w n a l m o s t o n l y b y s m a l l e r s h e e p , p a r t i c u l a r l y s u b a d u l t s a n d f e m a l e s a f t e r h a v i n g b e e n d i s t u r b e d b y a l a r g e r s h e e p . O c c a s i o n a l l y , f o l l o w i n g t h e h e a d s h a k e t h e a n i m a l b o u n c e s f o r w a r d , f r o l i c s , t h r e a t j u m p s a n d r u n s o n . T h e h e a d s h a k e m a y a l s o i n i t i a t e a t h r e a t j u m p , l e a d i n g o c c a s i o n a l l y t o a c l a s h . Y o u n g r a m s p e r f o r m t h i s d u r i n g p l a y . T y p i c a l l y , t h e c h i n i s p u l l e d i n , t h e h e a d a n d n e c k a r e r a i s e d a n d t h e h o r n s h e n c e i n c l i n e d f o r w a r d , d u r i n g t h e s h a k e . O n a l l o c c a s i o n s o b s e r v e d t h e s h e e p s h a k i n g t h e h e a d h a d i t s r u m p t o w a r d t h e d o m i n a n t . T h e h e a d s h a k e i s n o t a v e r y c o m m o n b e h a v i o u r . p a t t e r n . Q u a l i t a t i v e d i f f e r e n c e s i n t h e b e h a v i o u r o f S t o n e ' s . P a l l ' s  a n d b i g h o r n s h e e p : A l t h o u g h t h e r a c e s o f s h e e p w h i c h I s t u d i e d d i f f e r e d g r e a t l y i n c o a t c o l o u r a n d p a t t e r n i n g a s w e l l a s i n h o r n a n d g r o w t h c h a r a c t e r i s t i c s ( C o w a n , 1 9 4 0 ) , I c o u l d n o t d e t e c t a n y c o n s i s t e n t q u a l i t a t i v e d i f f e r e n c e i n t h e i r b e h a v i o u r . T h e b e h a v i o u r p a t t e r n s w h i c h S t o n e ' s s h e e p p e r f o r m e d w e r e s o v e r y s i m i l a r t o t h o s e o f b i g h o r n s a n d D a l l ' s , t h a t i f a n y d i f f e r e n c e e x i s t s , I d i d n o t d e t e c t i t . D a l l ' s s h e e p t e n d t o a s s u m e a s l i g h t l y m o r e e x a g g e r a t e d l o w - s t r e t c h i n w h i c h t h e y h o l d 5 9 u p t h e i r n o s e s a l i t t l e h i g h e r t h a n b i g h o r n s u s u a l l y d o . H o w e v e r , t h e l a t t e r o c c a s i o n a l l y p e r f o r m t h i s b e h a v i o u r p a t t e r n a s d o D a l l ' s a l s o , a n d t h e d i f f e r e n c e i s m o r e q u a n t i t a t i v e t h a n q u a l i t a t i v e . Q u a n t i t a t i v e d i f f e r e n c e s w i l l b e d i s c u s s e d l a t e r . 6 0 P A R T I I A N A N A L Y S I S O F T H E R U L E S O F S O C I A L B E H A V I O U R I n t r o d u c t i o n T h e a i m o f t h i s c h a p t e r i s t o d e s c r i b e s o m e o f t h e r u l e s w h i c h s h e e p f o l l o w w h e n i n t e r a c t i n g w i t h o n e a n o t h e r . T o t h i s e n d , q u a n t i t a t i v e d a t a h a v e b e e n g a t h e r e d a b o u t t h e f r e q u e n c y o f s o c i a l b e h a v i o u r p a t t e r n s , t h e i r s e q u e n c e a n d t h e s i t u a t i o n i n w h i c h t h e y o c c u r . T h e u n i t o f c o m p a r i s o n u s e d h e r e , i s t h e i n t e r a c t i o n . I t d e n o t e s t h e h a p p e n i n g s b e t w e e n t w o a n i m a l s f r o m t h e t i m e t h e y e n g a g e , t o t h e t i m e t h e y m o v e a p a r t a n d i g n o r e e a c h o t h e r . A n i n t e r a c t i o n i s h e n c e v e r y v a r i a b l e i n t i m e - i t m a y l a s t s e c o n d s , o r r a r e l y , s e v e r a l h o u r s . O n o c c a s i o n s t h e r e i s , i n a d d i t i o n , t h e d i f f i c u l t y o f d e c i d i n g w h e n a n i n t e r a c t i o n e n d e d a n d a n e w o n e b e g a n . F o r i n s t a n c e , w h e n s e v e r a l r a m s i n a g r o u p i n t e r a c t o n e m a y m o v e t e m p o r a r i l y f r o m h i s p a r t n e r a n d e n g a g e w i t h a n o t h e r o n l y t o r e t u r n a g a i n . W e r e t h e s e t w o i n t e r a c t i o n s o n t h e s a m e r a m o r h a d t h e r a m m e r e l y i n t e r r u p t e d t h e i n i t i a l i n t e r a c t i o n ? O r , i n a n i n t e r  a c t i o n b e t w e e n t w o r a m s o n e m o v e s o f f a l i t t l e , f e e d s t h e n r e t u r n s a g a i n t o h i s o p p o n e n t . O n e o r t w o i n t e r a c t i o n s ? I n b o t h e x a m p l e s , I t r e a t e d i t a s o n e i n t e r a c t i o n . B o t h p a r t n e r s 61 had to return to feed and separate from each other before the i n te rac t i on was declared f i n i s h e d . In group i n t e r  act ions (huddles) each ram had only one i n te rac t i on with each of the others regardless how often i t was in terrupted, how long the i n te r rup t ion l a s ted , or how long the huddle wore on. The frequency of various behaviour patterns i s ind icated in the graphs as patterns per 100 in terac t ions , or as patterns per i n t e r a c t i o n . The fo l lowing behaviour patterns were quant i f ied (abbreviat ions as used i n the graphs fo l low i n brackets) : Low-stretch (Lo.) horning the opponent*s body (HB) Front -k i ck or Laufeinschlag mounting (M) (L) Twist (T) threat-jump (TH.) Butt ing (B) s n i f f i n g and nuzz l ing of rear (S) Horn-threat (H) charging or rushing at opponent (Ru.) Rubbing (R) l i p c u r l or flehmen (F) Behaviour patterns which were rare such as e jacu la t i on , or the head-shake were l e f t out. L i c k i n g and nuzz l ing the opponent*s head were quant i f i ed under " rubb ing " . I recorded the response of sheep to being k icked or mounted with the symbols (o) or (-), the f i r s t meaning that no response at a l l occurred and the second, that the k icked or mounted sheep withdrew at once. The behaviour patterns quant i f ied are hence 62 t h o s e w h i c h s h e e p p e r f o r m t o w a r d s o n e a n o t h e r ; I i g n o r e d p a t t e r n s w h i c h w e r e n o t s p e c i f i c a l l y d i r e c t e d a t c o m p a n i o n s . T h e s e x - a g e c l a s s e s o f s h e e p ( P i g . 7) c a n h e a r r a n g e d i n o r d e r o f r e s e m b l a n c e . W h e n t h i s i s d o n e , t h e l a m b - w h i c h i s s m a l l e s t i n b o d y - a n d h o r n s i z e - w i l l b e f o u n d a t o n e e n d o f t h e s e r i e s , a n d t h e l a r g e f u l l c u r l e d r a m s ( c l a s s I V ) a t t h e o t h e r . T h e o t h e r c l a s s e s f o r m a s m o o t h c o n n e c t i n g s e r i e s , e a c h c l a s s d i f f e r i n g o n l y s l i g h t l y i n a p p e a r a n c e f r o m t h e f o l l o w i n g , a n d p r e c e d i n g o n e . T h i s c a n b e s e e n i n P i g . 7. T h e c l a s s e s i n c r e a s e i n b o d y s i z e t h r o u g h o u t t h e s e r i e s , q u i c k l y b e t w e e n l a m b a n d f e m a l e a n d m o r e s l o w l y f r o m y e a r l i n g t o c l a s s I V r a m . T h e s a m e i s t r u e f o r h o r n s i z e , o n l y t h a t h o r n s i z e i n c r e a s e s m o s t b e t w e e n c l a s s e s y e a r l i n g r a m t o c l a s s I V r a m . T h e d i f f e r e n c e s i n a p p e a r a n c e a r e d i f f e r e n c e s i n d e g r e e o n l y a n d t h e w h o l e s e r i e s c l a s s L . t o I V r e p r e s e n t s o n e v i s u a l g r a d i e n t . i n w h i c h t h e e w e a p p e a r s o n l y a s a " s m a l l h o r n e d m a l e . " I n t h e f i g u r e s i n t h i s s e c t i o n , I h a v e t r e a t e d t h i s a r r a n g e m e n t o f s h e e p c l a s s e s a s s u c h a g r a d i e n t . T h a t i s , e a c h c l a s s r e p r e s e n t s a c e r t a i n d e g r e e o f h o r n - b o d y s i z e d e v e l o p m e n t , o r " m a l e " a p p e a r a n c e . A n u m b e r o f d i f f e r e n t " s o c i a l s i t u a t i o n s " c o u l d b e r e c o g n i z e d . I n t h e n o r m a l s i t u a t i o n a n i n t e r a c t i o n b e t w e e n t w o s h e e p t o o k p l a c e w i t h o u t o t h e r s t a k i n g a n y n o t i c e o f i t , o r b e i n g i n a n y w a y c o n n e c t e d w i t h t h a t i n t e r a c t i o n . W h e n 63 rams interacted in a huddle (Pig. 80), I marked such inter actions and evaluated such interactions separately. Other situations were the actions of large, estrous ewe-guarding  rams on subordinate ones, the interactions of subordinate rams among themselves in the presence of an estrous ewe, the interactions of rams with estrous as opposed to non- estrous ewesr and the dominance fights of rams. Whenever the number of specific behaviour patterns i s compared from one situation to the next, the patterns appear always in the order - Lo., L, T, B, H, R, HB, M, Th., C, S, Ru., F. This happens to be the order of frequency with which the patterns appear in the interactions of big  horn rams in the normal situation. The patterns have been ranked, and this is, the rank order against which a l l other pattern frequencies from different social situations, species or sexes are compared. The rank order of behaviour patterns for bighorn rams in the normal situation, when larger rams in i t i a t e interactions on smaller, i s shown in Fig. 71. The graph has been heavily outlined from pattern low-stretch (Lo.) to class(C). Beyond this I added S. Ru., and F. These patterns, sniffing of rear, rushing and lipcurling are not entirely comparable to the preceding ones. The rush is not part of an interaction, i t jis one interaction. It begins and ends one interaction almost every time i t occurs. Sniffing 64 and. l i p c u r l i n g are behaviour patterns which have no soc i a l meaning but do occur i n s o c i a l i n te rac t i on s . Hence, I p laced them into each i n te rac t i on but outside the rank order of s o c i a l l y meaningful pat terns . Graphs of pattern f r e  quencies within in teract ions should be read as rank order d i s to r t i ons (using the bighorn ram rank order graph as com parison) • There i s no p a r t i c u l a r reason why the in teract ions of large bighorn rams on smaller ones during the normal s i tua t i on should be used to compare others t o , except that such in teract ions were rather common and d id contain a l l the behaviour patterns quant i f i ed . This cannot be stated f o r instance, of in teract ions between lambs. I used bighorn ram in teract ions simply because I had to have some bas is fo r comparison, and these struck me as convenient i n te rac t i on s . Results and Discussion Soc i a l preference The f i r s t question about the s o c i a l in teract ions of sheep i s : With whom does each c lass of sheep in teract vo lun t a r i l y ? F i g . 67 gives an answer to t h i s . Each of the seven graphs represents the percent d i s t r i bu t i ons of i n t e r  act ions i n i t i a t e d by one c lass of Stone*s sheep on others. 6 5 T h e t o t a l n u m b e r o f i n t e r a c t i o n s o n w h i c h e a c h g r a p h i s b a s e d , a n d t h e s y m b o l o f t h e c l a s s i n q u e s t i o n ( I V t o L . ) , i s i n d i c a t e d a b o v e e a c h g r a p h . F o r i n s t a n c e , c l a s s I V r a m s w e r e o b s e r v e d i n 6 5 4 i n t e r a c t i o n s ; t h e y i n t e r a c t e d m o s t f r e  q u e n t l y w i t h e w e s ( 3 6 $ ) , n e x t f r e q u e n t l y w i t h c l a s s I I r a m s (19%), a n d l e a s t f r e q u e n t l y w i t h l a m b s ( L . ) ( 4 $ ) . T h e g r a p h s f o r r a m s c l a s s I V - I I c a n b e d i r e c t l y c o m p a r e d w i t h e a c h o t h e r s i n c e r a m s o f t h e s e c l a s s e s l i v e i n t h e s a m e s o c i a l e n v i r o n m e n t . T h e s a m e i s t r u e f o r g r a p h s 0 y e a r l i n g t o l a m b , s i n c e t h e s e c l a s s e s l i v e i n t h e f e m a l e b a n d s . H o w e v e r , t h e s e t w o g r o u p s o f g r a p h s m a y , w i t h s o m e c a u t i o n , b e c o m p a r e d w i t h e a c h o t h e r s i n c e r a m s a n d e w e s d o c o m e t o g e t h e r f r o m e a r l y N o v e m b e r t i l l l a t e D e c e m b e r a n d i t i s d u r i n g t h i s p e r i o d t h a t m o s t o f t h e i n t e r a c t i o n s w e r e o b s e r v e d . I t i s e v i d e n t , t h a t w h e n e v e r r a m s i n i t i a t e i n t e r  a c t i o n w i t h e w e s , e w e s c o u l d d o t h e s a m e . H o w e v e r , t h e y d o riot. T h e g r a p h s i n F i g . 6 7 s h o w t h e f o l l o w i n g : ( 1 ) R a m s i n t e r a c t w i t h a l l s e x - a g e c l a s s e s o f s h e e p , w h e r e a s e w e s i n t e r a c t a l m o s t e x c l u s i v e l y w i t h s h e e p o f e q u a l o r s m a l l e r s i z e . ( 2 ) L a r g e r a m s i n t e r a c t m o r e w i t h r a m s t h a n d o s m a l l e r o n e s ( I V = 5 3 $ , I I I = 5 0 $ , I I = 3 4 $ o f a l l o b s e r v e d i n t e r a c t i o n s o n r a m s ) . ( 3 ) L a r g e r a m s i n t e r a c t l e s s w i t h s u b a d u l t f e m a l e s (<|>y) a n d l a m b s ( L . ) t h a n d o s m a l l e r o n e s . 6 6 ( 4 ) E w e s a n d s u b a d u l t s a s w e l l a s y e a r l i n g m a l e s i n t e r a c t v o l u n t a r i l y p r i m a r i l y w i t h s h e e p o f e q u a l o r s m a l l e r b o d y s i z e . I t i s a p p a r e n t t h a t t h e l a r g e r r a m s d i s t r i b u t e t h e i r i n t e r a c t i o n s o v e r a l l s e x e s a n d a g e s o f s h e e p . T h e n u m b e r o f i n t e r a c t i o n s w h i c h a c l a s s o f s h e e p p e r f o r m s w i t h a n o t h e r c l a s s , d e p e n d s t o s o m e e x t e n t o n h o w f r e q u e n t l y t h a t c l a s s w a s e n c o u n t e r e d . F o r i n s t a n c e , r a m s m a d e m o s t i n t e r a c t i o n s w i t h e w e s ( F i g . 6 7 ) . H o w e v e r , e w e s w e r e t h e m o s t c o m m o n c l a s s o f s h e e p i n t h e v i c i n i t y o f t h e a c t i n g r a m s , i . e . , t h e 6 5 4 i n t e r a c t i o n s o f c l a s s I V S t o n e ' s r a m s w e r e p e r f o r m e d i n t h e c l o s e p r e s e n c e o f 1 9 6 I V r a m s , 3 9 3 I I I r a m s , 6 4 9 I I r a m s , 2 5 1 6y., 9 4 7 e w e s . 4 0 0 ( j ) y . , a n d 5 0 9 l a m b s . T h i s r a i s e s t h e s e c o n d q u e s t i o n : D o s h e e p i n t e r a c t r a n d o m l y w i t h i n d i v i d u a l s o f a l l s e x - a g e c l a s s e s , o r d o t h e y p r e f e r t o i n t e r a c t w i t h p a r t i c u l a c l a s s e s ? F i g . 6 7 h a s a l r e a d y d e m o n s t r a t e d t h a t s m a l l b o d i e d s e x - a g e c l a s s e s t e n d t o p r e f e r s h e e p o f e q u a l o r s m a l l e r s i z e H o w e v e r , t h e p o s e d q u e s t i o n c a n b e a n s w e r e d m o r e p r e c i s e l y . O n e c a n c o m p a r e t h e p e r c e n t f r e q u e n c y w i t h w h i c h a c l a s s w a s c h o s e n f o r a n i n t e r a c t i o n , a n d t h e f r e q u e n c y w i t h w h i c h i t w a s p r e s e n t i n t h e s o c i a l e n v i r o n m e n t . T h u s c l a s s I V S t o n e ' s r a m s p e r f o r m e d 9 . 6 $ o f t h e i r i n t e r a c t i o n s o n o t h e r 67 c l a s s I V r a m s . H o w e v e r , o t h e r c l a s s I V r a m s m a d e u p o n l y 5.8$ o f a l l s h e e p I n t h e i r p r o x i m i t y . T h e r e f o r e , c l a s s I V r a m s a c t e d 9.6 / 5 . 8 , o r 1.6 t i m e s a s o f t e n o n c l a s s I V r a m s t h a n a n t i c i p a t e d , i f c l a s s I V r a m s h a d n o p r e f e r e n c e w h a t s o  e v e r . T h e r a t i o o f p e r c e n t f r e q u e n c y o f i n t e r a c t i o n s o n c l a s s x o v e r p e r c e n t f r e q u e n c y o f p r e s e n c e o f c l a s s x , i s c a l l e d a p r e f e r e n c e i n d e x . A p r e f e r e n c e i n d e x v a l u e o f 1 m e a n s t h a t t h e c l a s s o f s h e e p i n q u e s t i o n w a s c h o s e n a s o f t e n a s i t w a s p r e s e n t i n t h e s o c i a l e n v i r o n m e n t o f t h e a c t i n g c l a s s j n o c h o i c e h a s b e e n d e m o n s t r a t e d w h e r e t h e i n d e x v a l u e i s 1 . H o w e v e r , i f t h e i n d e x v a l u e i s l a r g e r ( o r s m a l l e r ) t h a n 1, t h e n t h e c l a s s h a s b e e n c h o s e n m o r e f r e q u e n t l y ( o r l e s s f r e q u e n t l y ) t h a n p r e s e n t . A, p r e f e r e n c e i n d e x v a l u e o f 0 .35 o f I I I r a m s f o r l a m b s , s h o w s t h a t I I I r a m s i g n o r e d t h e l a m b s m o s t o f t h e t i m e . T h e p r e f e r e n c e i n d e x m e t h o d i s a c r u d e m a n n e r o f a s s e s s i n g t h e s o c i a l p r e f e r e n c e s o f e a c h s h e e p c l a s s ; h o w e v e r , i t d o e s g i v e r e p e a t a b l e r e s u l t s 9 a n d c o n c l u s i o n s b a s e d o n i t a r e s u p p o r t e d b y d i f f e r e n t d a t a . W e c a n e s t i m a t e t h e s o c i a l p r e f e r e n c e o f a s h e e p c l a s s i n a s e c o n d m a n n e r . I f o n e c l a s s o f s h e e p p r e f e r s a n o t h e r c l a s s , i t i s l i k e l y t h a t i t w i l l i n t e r a c t l o n g e r , a n d s h o w m o r e b e h a v i o u r p a t t e r n s t o w a r d s a m e m b e r o f t h e p r e f e r r e d c l a s s t h a n t o w a r d s a l e s s p r e f e r r e d c a t e g o r y . T h i s w e d o f i n d . I n F i g . 68 t h e s o l i d c i r c l e s (t) 68 s t a n d f o r S t o n e ' s s h e e p p r e f e r e n c e i n d e x d a t a ; t h e o p e n c i r c l e (0) f o r S t o n e ' s s h e e p , f o r t h e n u m b e r o f b e h a v i o u r p a t t e r n s p e r f o r m e d p e r i n t e r a c t i o n o n e a c h c l a s s i n t e r a c t e d w i t h ; t h e s o l i d l i n e s t a n d s f o r b i g h o r n s h e e p p r e f e r e n c e i n d e x d a t a . P i g . 68 s h o w s t h e f o l l o w i n g : ( 1 ) R a m s p r e f e r t o i n t e r a c t w i t h r a m s o f t h e i r o w n s i z e c l a s s o r o f a s i z e c l a s s c l o s e t o t h e i r o w n . S e c o n d l y , r a m s p r e f e r e w e s . ( 2 ) D e s p i t e a c e r t a i n a m o u n t o f p r e f e r e n c e , r a m s i n t e r a c t w i t h a l l s e x - a g e c l a s s e s o f s h e e p . (3 ) R a m s a r e l e a s t i n t e r e s t e d i n s u b - a d u l t s . (4) P r e f e r e n c e i n d e x d a t a a n d t h e f r e q u e n c y w i t h w h i c h r a m s p e r f o r m e d b e h a v i o u r p a t t e r n s p e r i n t e r a c t i o n o n a l l c l a s s e s , l e a d t o t h e s a m e c o n c l u s i o n : I I I r a m s n o t o n l y c h o o s e o t h e r c l a s s I I I r a m s m o r e f r e q u e n t l y t h a n o t h e r s , b u t p e r f o r m m o r e b e h a v i o u r p a t t e r n s o n t h e m t h a n o n o t h e r r a m s . ( 5 ) T h e d a t a a r e n o t c o m p l e t e l y c o n s i s t e n t , b u t a r e c o n s i s t e n t e n o u g h t o e s t a b l i s h t h e c o n c l u s i o n s o u t l i n e d a b o v e . T h e i n d e x o f c h o i c e d a t a f o r y e a r l i n g r a m s o f b o t h s p e c i e s d o e s n o t f o l l o w e n t i r e l y t h a t o f l a r g e r r a m s . T h e y e a r l i n g s c h o o s e t h e i r o w n c l a s s r e l a t i v e l y m o s t f r e q u e n t l y . T h e i r p r e f e r e n c e f o r e w e s , h o w e v e r , d o e s n o t a p p e a r t o o g r e a t . T h e r e i s a g o o d r e a s o n f o r t h i s . Y e a r l i n g r a m s r e m a i n s u b o r d i n a t e t o e w e s t i l l t h e y h a v e s u r p a s s e d t h e m i n 6 9 b o d y s i z e . T h i s m a y o c c u r a t 1 6 - 1 8 m o n t h s o f a g e , b u t f o r s o m e r a m s i t d o e s n o t h a p p e n t i l l 2 7 - 3 0 m o n t h s o f a g e . A s l o n g a s t h e y e a r l i n g r a m s a r e n o t t o t a l l y d o m i n a n t o v e r e w e s , i t a p p e a r s t o b e r e a s o n a b l e t h a t t h e y c h o o s e e w e s l e s s f r e q u e n t l y t o i n t e r a c t w i t h t h a n o t h e r y e a r l i n g r a m s . I n t e r a c t i o n i n i t i a t i o n T h e n e x t q u e s t i o n i s : H o w a r e t h e s o c i a l i n t e r a c t i o n s o f s h e e p i n i t i a t e d ? T h e i n t e r a c t i o n s a r e i n i t i a t e d e i t h e r i n a l o w - s t r e t c h o r w i t h a w e a k h o r n - t h r e a t ; o c c a s i o n a l l y n o p a r t i c u l a r p a t t e r n i s u s e d . I f w e p l o t t h e p e r c e n t f r e q u e n c y w i t h w h i c h r a m s i n i t i a t e i n t e r a c t i o n s i n l o w - s t r e t c h o n l a r g e r a n d s m a l l e r c o m p a n i o n s , w e f i n d t h a t t h e l o w - s t r e t c h i s u s e d p r e d o m i n a n t l y t o w a r d s s m a l l e r r a m s ( F i g . 6 9 ) . T h i s i s t r u e f o r S t o n e ' s a n d b i g h o r n s h e e p . T h e l a r g e r r a m s u s e m a i n l y t h e l o w - s t r e t c h a n d t h e s m a l l e r m a i n l y t h e h o r n - t h r e a t w h e n a p p r o a c h i n g a c o m p a n i o n j u s t p r i o r t o t h e i n t e r a c t i o n . E w e s a n d s u b - a d u l t s i n i t i a t e v e r y f e w i n t e r a c t i o n s i n l o w - s t r e t c h . A d u l t S t o n e ' s e w e s d i d s o i n o n l y 1 4 $ o f t h e i n t e r a c t i o n s ( n = 1 5 7 ) , a n d y e a r l i n g e w e s i n o n l y 1 0 $ ( n = 5 8 ) . T h e m a n n e r i n w h i c h s h e e p i n i t i a t e a n i n t e r a c t i o n d e p e n d s o n t h e i r s e x a n d s i z e r e l a t i v e t o t h e c o m p a n i o n s t h e y i n t e r a c t w i t h . I t s h o u l d b e n o t e d t h a t t h e d a t a i n F i g . 6 9 d e m o n s t r a t e t h a t s h e e p a r e a w a r e o f t h e d o m i n a n c e p o s i t i o n 7 0 o f t h e i r c o m p a n i o n b e f o r e t h e y i n t e r a c t w i t h h i m . B e h a v i o u r p a t t e r n s e q u e n c e T h e n e x t q u e s t i o n i s : I s t h e r e a d e f i n i t e p r e d i c t a b l e o r d e r w h i c h b e h a v i o u r p a t t e r n s f o l l o w a f t e r a n i n i t i a t i o n ? T h i s q u e s t i o n w a s i n v e s t i g a t e d a s f o l l o w s : I r e c o r d e d t h e b e h a v i o u r p a t t e r n w h i c h i m m e d i a t e l y f o l l o w e d t h e a p p r o a c h . F o r i n s t a n c e , i f a r a m a p p r o a c h e d i n l o w - s t r e t c h t h e n d e l i v e r e d a f r o n t k i c k , I r e c o r d e d ( a ) t h e m a n n e r o f a p p r o a c h ( l o w - s t r e t c h ) a n d ( b ) t h e f o l l o w i n g p a t t e r n ( f r o n t k i c k ) . N e x t I r a n k e d t h e b e h a v i o u r p a t t e r n s w h i c h f o l l o w e d t h e a p p r o a c h p a t t e r n i n t h e i r o r d e r o f f r e q u e n c y . I u s e d t h e i n t e r a c t i o n s o f l a r g e S t o n e ' s r a m s o n s m a l l e r o n e s , w h e n t h e l a r g e r a p p r o a c h e d i n l o w - s t r e t c h a s a b a s i s f o r c o m p a r i s o n ( F i g . 7 0 A § , l a r g e r o n s m a l l e r ) . I t c a n b e s e e n t h a t a l m o s t a n y b e h a v i o u r p a t t e r n c o u l d f o l l o w t h e i n i t i a t i n g l o w - s t r e t c h . H e n c e n o d e f i n i t e o r d e r i n w h i c h b e h a v i o u r p a t t e r n s f o l l o w e a c h o t h e r c o u l d b e e s t a b l i s h e d , h o w e v e r , t h i s d o e s n o t m e a n t h a t o n e c o u l d n o t p r e d i c t w h a t w o u l d f o l l o w o n c e a n i n t e r a c t i o n w a s i n i t i a t e d . F i g . 7 0 s h o w s s i x g r o u p s o f g r a p h s , s e p a r a t e d i n t o A. a n d B s u b g r o u p s . A r e p r e s e n t s i n t e r a c t i o n s i n i t i a t e d i n l o w - s t r e t c h a n d B , i n t e r a c t i o n s n o t i n i t i a t e d i n l o w - s t r e t c h . T h e n u m b e r s a b o v e e a c h g r a p h i n d i c a t e t h e n u m b e r o f i n t e r  a c t i o n s e a c h g r a p h i s b a s e d o n . T h e c i r c l e s r e p r e s e n t S t o n e ' s 71 sheep data, the s o l i d l i n e bighorn data, the l i n e without c i r c l e s represents comboned bighorn and Stone's sheep data. The open c i r c l e (0) represents data from Stone's year l ing ewes. A l l contact behaviour (nuzzl ing, horning, rubbing) has been brought together under rubbing (R). The abscissa represents the behaviour patterns other than low-stretch which may fo l low the i n i t i a l approach pat tern, ranked i n the order of frequency as they occur i n in terac t ions of large Stone's rams on smaller ones. It can be seen f o r instance that any in teract ions of small rams on l a rger ones, when the smaller d id not use a low-stretch to i n i t i a t e the i n te rac t i on (B), small Stone's (0) or bighorn rams (-), used rubbing (R) as the f i r s t behaviour pattern a f t e r i n i t i a t i o n . A study of the graphs under the s i tuat ions ind icated shows the fo l lowing: (1) There i s no d e f i n i t e sequence i n which behaviour patterns fo l low in the s o c i a l i n te rac t i on s . Any soc i a l behaviour pattern may fo l low a f te r i n i t i a t i o n , be t h i s in low-stretch or not, however, each pattern does have a s i tua t ion depending probably on appearance. (2) The p robab i l i t y with which a given behaviour pattern appears a f t e r i n i t i a t i o n depends on: (a) whether the i n i t i a t i o n was i n low-stretch or not . Thus, when larger sheep in teracted with small ones, d i sp lay patterns ( f r on t - k i ck ; , 72 twist ) usual ly fo l lowed the low-s t retch, while contact (rubbing, horning, nuzzl ing) and aggressive patterns (Butt, c l a sh , threat-jump) fol lowed i f no low-stretch was used, (b) whether a l a rger i n i t i a t e d an engagement on a smaller one or v ice versa . In the former, d isp lay patterns pre dominated, and i n the l a t t e r , contact patterns, (c) whether a male or a female were i n i t i a t e d on by rams. In the former case, d i sp lay patterns predominated, in the l a t t e r , s n i f f i n g and nuzz l ing of the rear , (d) whether a male or a female i n i t i a t e d an engagement. Ewes, un l ike rams, use predomi nantly aggressive patterns and few d isp lays , (e) whether a young ram or an older one i n i t i a t e d an engagement ( i . e . (f yea r l i ng on Q, versus 0* on (J)). Young rams use more aggres s ive patterns and fewer d i sp lay patterns than older ones. (3) Stone's and bighorn sheep behave very s im i l a r l y under s im i l a r circumstances f o r a l l s i tuat ions compared. The most important po int , i n addit ion to the lack of a f i x e d pattern sequence, displayed by the data in F i g . 81, i s that the behaviour of sheep towards one another i s quite p red ic tab le . Assuming that I saw a smaller ram move in a weak horn threat towards a l a rger one, then I would predict that the larger would be horned, rubbed or nuzzled, and i n be t te r than 75 out of 100 times t h i s would be co r rec t . 7 3 N e x t t o b e e x a m i n e d i s t h e b e h a v i o u r o f s h e e p w h i c h h a v e i n i t i a t e d i n t e r a c t i o n s . W h a t k i n d o f b e h a v i o u r p a t t e r n s a n d h o w m a n y a r e e x c h a n g e d b e t w e e n t h e i n t e r a c t i n g c o m p a n i o n s ? T h e " n o r m a l " i n t e r a c t i o n s A f t e r r e j e c t i n g t h e h y p o t h e s i s t h a t s o c i a l b e h a v i o u r p a t t e r n s a r e o r g a n i z e d i n p r e d i c t a b l e s e q u e n c e , I s h a l l p r e s e n t t h e s o c i a l p a t t e r n s w h i c h o c c u r w i t h i n i n t e r a c t i o n s r a n k e d i n o r d e r o f f r e q u e n c y . T h e s t a n d a r d r a n k o r d e r , a g a i n s t w h i c h t h e f r e q u e n c y o f b e h a v i o u r p a t t e r n s i n v a r i o u s i n t e r a c t i o n s w i l l b e c o m p a r e d , i s t h a t o f p a t t e r n s p e r f o r m e d b y l a r g e b i g h o r n r a m s o n s m a l l o n e s i n t h e " n o r m a l " s i t u a t i o n . T h e d a t a i n P i g . 7 1 a r e l a i d o u t i n t h e f o l l o w i n g m a n n e r : I n e a c h f i g u r e , t h e u p p e r g r a p h s h o w s t h e a c t i o n o f t h e l a r g e r s h e e p , a n d t h e l o w e r o f t h e s m a l l e r o n e . T h e b i g h o r n d a t a a r e r e p r e s e n t e d b y a s o l i d l i n e c o n n e c t i n g d a t a p o i n t s ; S t o n e ' s y e a r l i n g e w e s a r e r e p r e s e n t e d b y a b r o k e n l i n e ; t h e S t o n e ' s s h e e p d a t a a r e r e p r e s e n t e d a s s o l i d b a r s . T h e n u m b e r s a b o v e e a c h g r a p h r e p r e s e n t t h e n u m b e r o f i n t e r  a c t i o n s o n w h i c h e a c h g r a p h i s b a s e d , t h u s , e a c h f i g u r e r e p r e s e n t s o n e s o c i a l s i t u a t i o n ( i . e . i n t e r a c t i o n i n i t i a t e d b y l a r g e r r a m o n s m a l l e r o n e ) a n d t h e f r e q u e n c y w i t h w h i c h t h e v a r i o u s p a t t e r n s w e r e d e a l t o u t b y t h e l a r g e r a n d t h e s m a l l e r p a r t n e r . A n e x a m i n a t i o n o f t h e s u b - f i g u r e s i n F i g . 7 1 s h o w s t h e f o l l o w i n g : 7 4 ( 1 ) A n y s o c i a l b e h a v i o u r p a t t e r n , i n c l u d i n g t h o s e o f c o u r t s h i p ( s n i f f i n g r e a r , m o u n t i n g ) , c a n o c c u r i n t h e s o c i a l i n t e r a c t i o n s o f r a m s , a n d o f e w e s . ( 2 ) T h e b e h a v i o u r p a t t e r n s u s e d m o s t f r e q u e n t l y b y t h e l a r g e r a m a r e u s e d l e s s f r e q u e n t l y b y t h e s m a l l r a m . O n e c a n h e n c e d i v i d e b e h a v i o u r p a t t e r n s i n t o t w o g r o u p s ; t h o s e u s e d p r i m a r i l y b y t h e l a r g e r r a m , a n d t h o s e p r i m a r i l y b y t h e s m a l l e r r a m . I n t h e n o r m a l i n t e r a c t i o n s o f S t o n e ' s r a m s , t h e f o l l o w i n g b e h a v i o u r p a t t e r n s a r e u s e d p r i m a r i l y b y t h e d o m i n a n t : R u s h ( 1 0 0 $ ) , t w i s t ( 1 0 0 $ ) , f r o n t - k i c k ( 9 4 $ ) , l o w - s t r e t c h ( 8 1 $ ) , m o u n t i n g ( 8 0 $ ) ; t h e s e p a t t e r n s a r e u s e d s o m e w h a t l e s s f r e q u e n t l y b y t h e d o m i n a n t - h o r n - t h r e a t ( 4 7 $ ) , b u t t ( 4 3 $ ) ; t h e s e b e h a v i o u r p a t t e r n s a r e u s e d l e a s t f r e  q u e n t l y - t h r e a t - j u m p ( 2 2 $ ) , c l a s h ( 2 1 $ ) , r u b b i n g ( 4 $ ) , h o r n i n g t h e o p p o n e n t ' s b o d y ( 2 $ ) ( n = 1 8 8 0 i n t e r a c t i o n s ) . D i s p l a y , s e x u a l b e h a v i o u r p a t t e r n s a n d c h a s i n g a w a y a r e v i r t u a l l y t h e p r e r o g a t i v e o f t h e d o m i n a n t , t h e c o n t a c t p a t t e r n s a r e u s e d a l m o s t e n t i r e l y b y t h e s u b o r d i n a t e . T h e a g g r e s s i v e p a t t e r n s a r e u s e d b y b o t h , b u t a r e i n i t i a t e d m a i n l y b y t h e s u b o r d i n a t e . I f w e c o m p a r e t h e n o r m a l i n t e r a c t i o n s o f r a m s i n i t i a t e d b y t h e l a r g e r ( P i g . 7 1 A ) v e r s u s t h o s e i n i t i a t e d b y t h e s m a l l e r ( F i g . 7 1 B ) , t h e n t h e f o l l o w i n g w i l l b e f o u n d : ( l ) I n i n t e r a c t i o n s i n i t i a t e d b y t h e s m a l l e r r a m , t h e s m a l l e r p e r f o r m s m o r e p a t t e r n s t h a n i n t h e c o n v e r s e s i t u a t i o n , a n d h e p e r f o r m s m o r e p a t t e r n s t h a n t h e l a r g e r r a m . 7 5 ( 2 ) T h e s u b o r d i n a t e u s e s t h e s a m e p a t t e r n s , a n d w i t h t h e s a m e r e l a t i v e f r e q u e n c y o n t h e d o m i n a n t , r e g a r d l e s s o f w h e t h e r t h e l a t t e r i n i t i a t e d t h e i n t e r a c t i o n o r n o t . T h e o n l y e x c e p t i o n i s t h a t t h e s u b o r d i n a t e u s e s m o r e l o w - s t r e t c h e s ( 1 0 . ) a n d f r o n t - k i c k s ( L ) w h e n h e i n i t i a t e s a n i n t e r a c t i o n . T h e n o r m a l f e m a l e i n t e r a c t i o n s ( F i g . 7 1 C ) d i f f e r f r o m t h o s e o f m a l e s i n t h e f o l l o w i n g w a y s : ( 1 ) F e m a l e s u s e v e r y f e w d i s p l a y a n d a l m o s t n o c o n t a c t p a t t e r n s . T h e y u s e p r i m a r i l y a g g r e s s i v e p a t t e r n s . ( 2 ) T h e l a r g e f e m a l e s r e c e i v e f e w r e s p o n s e s f r o m t h e s m a l l e r o n e s . A s i n t h e r a m i n t e r a c t i o n s , S t o n e ' s a n d b i g h o r n e w e s b e h a v e r a t h e r s i m i l a r l y , w h i l e y e a r l i n g f e m a l e s b e h a v e v e r y s i m i l a r l y t o a d u l t o n e s ( F i g . 7 1 C ) . T h e n a t u r e o f i n t e r a c t i o n s b e t w e e n r a m s , t h a t i s , t h e i r b e h a v i o u r p a t t e r n c o n t e n t s a n d f r e q u e n c i e s , v a r i e s w i t h t h e s o c i a l s i t u a t i o n . F i g . 7 1 i l l u s t r a t e d t h e n o r m a l i n t e r a c t i o n s . L e t u s n o w e x a m i n e t h e " h u d d l e " . T h e h u d d l e I n t h i s s i t u a t i o n m o s t r a m s o f o n e g r o u p g e t t o g e t h e r o n a r i d g e a n d w h i l e s t a n d i n g o r m o v i n g a s a t i g h t k n o t ( F i g . 8 0 ) , i n t e r a c t o n e a c h o t h e r . F i g . 7 2 A , s h o w s t h e p a t t e r n f r e  q u e n c y d i s t r i b u t i o n i n " n o r m a l " i n t e r a c t i o n s o f l a r g e b i g  h o r n r a m s o n s m a l l e r o n e s , a s c o m p a r e d t o i n t e r a c t i o n s o f 76 t h e s a m e k i n d i n " h u d d l e s " . I t c a n h e s e e n t h a t : (1) H u d d l e i n t e r a c t i o n s l a s t l o n g e r a n d c o n t a i n m o r e p a t t e r n s , (2) S u b o r d i n a t e r a m s p e r f o r m m o r e p a t t e r n s i n t h e " h u d d l e " s i t u a t i o n t h a n i n t h e n o r m a l o n e , b u t t h a t t h e p r o p o r t i o n s o f b e h a v i o u r p a t t e r n s c o m m o n l y u s e d b y s u b o r d i n a t e r a m s r e m a i n s s i m i l a r , (3) S u b o r d i n a t e r a m s p e r f o r m m o r e d i s p l a y p a t t e r n s i n t h e " h u d d l e " t h a n i n t h e " n o r m a l " i n t e r a c t i o n . ( 4 ) D o m i n a n t a n d s u b o r d i n a t e r a m s t h r e a t - j u m p , c l a s h a n d b u t t c o n s i d e r a b l y m o r e i n t h e " h u d d l e " i n t e r a c t i o n s . I i n t e r p r e t t h e h u d d l e a s a g a t h e r i n g o f p l a y i n g r a m s i n w h i c h t h e s u b o r d i n a t e , s m a l l e r r a m s , a r e l e a s t i n  h i b i t e d . T h i s i s i n d i c a t e d b y t h e o c c a s i o n a l m o u n t i n g o f a l a r g e r b y a s m a l l e r r a m , t h e f r e q u e n t t h r e a t - j u m p s w h i c h a r e a c c o m p a n i e d b y h e a d - s h a k i n g ( w h i c h d o e s n o t o c c u r i n d o m i n a n c e f i g h t s ) a n d t h e o c c a s i o n a l d i s i n t e g r a t i o n o f t h e h u d d l e i n t o a g r o u p o f f r o l i c k i n g , c l a s h i n g r a m s . H o w e v e r , p l a y o r n o t , i n h u d d l e s t h e l a r g e r a n d s m a l l e r r a m s a c t s t r i c t l y i n a c c o r d a n c e w i t h t h e i r r a n k a n d t h e b r e a k - d o w n o f b e h a v i o u r i n t o t h a t t y p i c a l o f t h e s m a l l e r o r s u b o r d i n a t e a n d t h a t o f t h e l a r g e r o r d o m i n a n t i s e n t i r e l y r e c o g n i z a b l e . 7 7 B e h a v i o u r o f t h e d o m i n a n t c l a s s I V r a m g u a r d i n g a n e s t r o u s e w e I n F i g . 7 2 B t h e " n o r m a l " i n t e r a c t i o n s o f l a r g e S t o n e ' s r a m s o n s m a l l e r o n e s , a r e c o m p a r e d t o t w o o t h e r k i n d s o f i n t e r a c t i o n s . O n e i s t h e i n t e r a c t i o n o f t h e e w e - g u a r d i n g d o m i n a n t r a m w i t h s u b o r d i n a t e r a m s . S u c h i n t e r a c t i o n s s h o w t h e f o l l o w i n g : ( 1 ) T h e y a r e b r i e f . T h e d e f e n d i n g d o m i n a n t d i s p l a y s m u c h l e s s t h a n i n " n o r m a l " i n t e r a c t i o n s . ( 2 ) T h e y a r e h i g h l y a g g r e s s i v e . I n a b o u t h a l f o f t h e i n t e r a c t i o n s t h e l a r g e d e f e n d i n g r a m c h a r g e s w i t h l o w e r e d h e a d a t t h e s m a l l e r s u b o r d i n a t e s . ( 3 ) S m a l l r a m s s h o w f e w p a t t e r n s i n r e p l y . I n t h i s v e r y t e n s e s o c i a l s i t u a t i o n t h e s u b o r d i n a t e s a v o i d t h e d o m i n a n t w h i c h w o u l d b e h i g h l y u n u s u a l f o r t h e " n o r m a l " o r " h u d d l e " s i t u a t i o n s . T h e s e c o n d k i n d o f i n t e r  a c t i o n a m o n g r a m s a b o u t t h e e s t r o u s e w e , i s t h a t o f s u b  o r d i n a t e s a m o n g e a c h o t h e r . B e h a v i o u r o f s u b o r d i n a t e r a m s a b o u t e s t r o u s e w e F i g . 7 2 B ( - . - . - ) s h o w s t h e p a t t e r n f r e q u e n c y o f s u b  o r d i n a t e r a m s i n t e r a c t i n g o n e a c h o t h e r , a s c o m p a r e d t o t h e " n o r m a l " i n t e r a c t i o n o f l a r g e r o n s m a l l e r S t o n e ' s r a m s . I t c a n b e s e e n t h a t : ( l ) T h e " n o r m a l " i n t e r a c t i o n s a n d t h o s e a b o u t t h e e s t r o u s e w e a r e v e r y s i m i l a r e x c e p t t h a t m o u n t i n g s b y t h e l a r g e r t a k e p l a c e w i t h g r e a t f r e q u e n c y . 78 ( 2 ) T h e s m a l l e r s u b o r d i n a t e r a m d o e s n o t " r e p l y " a s f r e q u e n t l y t o t h e l a r g e r o n e i n t e r a c t i n g w i t h h i m a s i n t h e " n o r m a l " s i t u a t i o n . I n a l l p r e v i o u s s i t u a t i o n s , t h e b e h a v i o u r o f t h e s m a l l e r , s u b o r d i n a t e r a m d i f f e r e d a p p r e c i a b l y f r o m t h a t o f t h e l a r g e r o r d o m i n a n t o n e . T h i s i s n o t t r u e f o r t h e n e x t s i t u a t i o n . D o m i n a n c e f i g h t s T h e s e a r e i n t e r a c t i o n s b e t w e e n t w o s h e e p o f e q u a l b o d y a n d h o r n s i z e w h i c h h a v e m e t f o r t h e f i r s t t i m e a n d a r e e s t a b l i s h i n g t h e i r r e s p e c t i v e d o m i n a n c e r a n k s . F i g . 7 3 s h o w s t h e f r e q u e n c y w i t h w h i c h t w o r a m s e n g a g e d i n a l o n g d o m i n a n c e f i g h t i n M a r c h , 1 9 6 2 . T h i s f i g h t b e t w e e n t w o c l a s s I I I S t o n e ' s r a m s i s d i s c u s s e d i n a l a t e r s e c t i o n i n d e t a i l ( p . 9 0 ) . N o t e t h a t e a c h r a m a c t e d a s i f h e w e r e t h e d o m i n a n t . B o t h u s e d m a i n l y d i s p l a y p a t t e r n s o n e a c h o t h e r , i n t e r r u p t e d b y s e v e r e c l a s h e s . T h e y u s e d t h e s a m e p a t t e r n s w i t h s i m i l a r f r e q u e n c i e s . C o n t a c t p a t t e r n s ( h o r n i n g , r u b b i n g , n u z z l i n g ) a r e a l m o s t a b s e n t . T h e r a m w h i c h u s e d m o s t b u t t s , a n d i n i t i a t e d m o s t c l a s h e s - G - r a m - w a s a l s o t h e o n e w h o u s e d f e w e r d i s p l a y p a t t e r n s . H e l o s t t h e d o m i n a n c e f i g h t . A d o m i n a n c e f i g h t l a s t s t i l l o n e o f t h e o p p o n e n t s b e g i n s t o u s e c o n t a c t p a t t e r n s a n d h e n c e s t o p s a c t i n g a s i f h e w e r e t h e l a r g e r . 7 9 I n P i g . 7 3 I r e p l a c e d p a t t e r n S w i t h " h o r n i n g o f g r o u n d " ( H G ) . B o t h r a m s u s e d i t r e a s o n a b l y f r e q u e n t l y d u r i n g t h e d o m i n a n c e f i g h t . I n t e r a c t i o n s b e t w e e n r a m s a n d e w e s F i g . 7 4 4 s h o w s t h e f r e q u e n c y o f b e h a v i o u r p a t t e r n s u s e d w h e n r a m s o l d e r t h a n 3 y e a r s i n t e r a c t w i t h n o n - e s t r o u s e w e s . A g a i n t h e b e h a v i o u r o f S t o n e ' s a n d b i g h o r n s h e e p i s v e r y s i m i l a r . F i g . 7 4 B s h o w s t h e b e h a v i o u r o f y e a r l i n g S t o n e ' s r a m s i n t e r a c t i n g w i t h e w e s . F i g u r e s 7 4 A & B s h o w t h e f o l l o w i n g : (1) R a m s u s e t h e s a m e p a t t e r n s t o w a r d s n o n - e s t r o u s e w e s a s t o w a r d s s m a l l e r r a m s , b u t w i t h s o m e w h a t d i f f e r e n t f r e q u e n c i e s . (2) I n t e r a c t i o n s w i t h n o n - e s t r o u s e w e s d i f f e r i n t h a t r a m s u s e m o r e t w i s t s ( T ) , d o m o r e r e a r e n d s n i f f i n g a n d p e r f o r m m o r e l i p c u r l s , t h a n i n i n t e r a c t i o n s w i t h s m a l l e r m a l e s . F u r t h e r m o r e , t h e y u s e f e w e r a g g r e s s i v e p a t t e r n s . ( 3 ) U n l i k e s u b o r d i n a t e r a m s i n t h e " n o r m a l " s i t u a t i o n , n o n - e s t r o u s e w e s r e p l y w i t h v e r y f e w b e h a v i o u r p a t t e r n s t o l a r g e r a m s . ( 4 ) Y e a r l i n g r a m s d i f f e r f r o m l a r g e r r a m s i n t h a t t h e y u s e f e w e r d i s p l a y p a t t e r n s t o w a r d s t h e e s t r o u s e w e , t h e y b u t t ( B ) a n d m o u n t (M) t h e e w e m o r e a n d p e r f o r m f e w e r l i p c u r l s . E w e s r e p l y t o y e a r l i n g r a m s m o r e o f t e n t h a n l a r g e r r a m s . 8 0 T h e i n t e r a c t i o n s o f r a m s w i t h n o n - e s t r o u s e w e s a p p e a r s o m e w h a t a l t e r e d i n t e r a c t i o n s o f l a r g e r a m s w i t h s m a l l e r o n e s . T h e d i f f e r e n c e s i n t h e r a m - r a m a n d r a m - e w e i n t e r a c t i o n s a l m o s t d i s a p p e a r i f t h e s e i n t e r a c t i o n s o c c u r a b o u t a n d o n t h e e s t r o u s e w e ( P i g . b 7 5 ) . I n F i g . 8 6 i t s h o w s t h a t t h e k i n d a n d f r e q u e n c y o f p a t t e r n s s h o w n b y t h e r a m o n t h e e w e i n h e a t ( - ) , a n d s u b o r d i n a t e m a l e s t o w a r d s e a c h o t h e r ( - . - . - ) , a s w e l l a s t h e r e p l y o f t h e s m a l l e r s h e e p a r e v e r y s i m i l a r i n e a c h c a s e . T h e e s t r o u s e w e i s n o t Y 1 o n l y t r e a t e d a s i f s h e w e r e a s m a l l r a m , b u t s h e a l s o r e p l i e s a s i f s h e w e r e a s m a l l r a m . T h e r e a r e m i n o r d i f f e r e n c e s ; t h e e w e h o r n - t h r e a t s m o r e f r e q u e n t l y , s h e r u b s h e r b o d y o c c a s i o n a l l y a l o n g t h e c h e s t o f t h e l a r g e r a m b r e e d i n g h e r , s h e p e r f o r m s a f e w c o q u e t j u m p s ( p . i l 7 F i g . 9 4 ) , h o w e v e r , o n t h e w h o l e h e r b e h a v i o u r r e s e m b l e s t h a t o f t h e s m a l l e r r a m . T h e d a t a i n F i g . 7 5 g i v e r i s e t o a m a j o r h y p o t h e s i s : R a m s d o n o t d i f f e r e n t i a t e c o n s p e c i f i c s o n t h e b a s i s o f s e x b u t o n t h e b a s i s o f r e l a t i v e s i z e . A l l " s m a l l e r " s h e e p - i r r e s p e c t i v e o f s e x - a r e t r e a t e d b y r a m s i n t h e s a m e m a n n e r . T h u s : : a c l a s s I V r a m t r e a t s s u b o r d i n a t e c l a s s I V r a m s a s i f t h e y w e r e e w e s , a n d t h e d i f f e r e n c e s i n t h e i n t e r a c t i o n s w i t h n o n - e s t r o u s e w e s , a r i s e f r o m t h e e w e s * r e a c t i o n t o t h e r a m s b e h a v i o u r . 8 1 I c o n t e n d t h a t i n s h e e p s o c i e t y t h e r e i s n o " f e m a l e " i n t h e u s u a l s e n s e , r a t h e r t h e f e m a l e a p p e a r s t o r a m s a s a h i g h l y d e s i r a b l e s u b o r d i n a t e . R a m s u s e m o r e c o u r t s h i p p a t t e r n s t o w a r d s s m a l l e r r a m s , t h e m o r e t h e s e r a m s r e s e m b l e a f e m a l e . F i g . 7 6 4 s h o w s t h e f r e q u e n c y p e r 1 0 0 i n t e r a c t i o n s w i t h w h i c h S t o n e ' s a n d b i g h o r n r a m s e x a m i n e d t h e r e a r o f t h e v a r i o u s s e x - a g e c l a s s e s o f s h e e p a n d F i g . 7 6 B s h o w s h o w f r e q u e n t l y t h e r a m s m o u n t e d t h e m . I t i s e v i d e n t t h a t t h e m o r e r a m s l o o k e d l i k e e w e s , t h e m o r e t h e y w e r e e x a m i n e d a b o u t t h e r e a r a n d m o u n t e d . I t w a s n o t e d e a r l i e r t h a t t h e i n t e r a c t i o n s o f r a m s o n n o n - e s t r o u s e w e s d i f f e r e d q u a n t i t a t i v e l y f r o m t h o s e o n s m a l l e r r a m s , b u t t h e i n t e r a c t i o n s o n e s t r o u s e w e s w e r e q u i t e s i m i l a r t o t h o s e o f r a m s o n e a c h o t h e r i n t h e p r e s e n c e o f e s t r o u s e w e s . F u r t h e r m o r e , n o t e i n F i g . 7 6 B t h a t m a l e a n d f e m a l e y e a r l i n g s w e r e m o u n t e d b y r a m s m o r e f r e q u e n t l y t h a n a d u l t , n o n - e s t r o u s e w e s . T h e s e d i f f e r e n c e s a p p e a r t o b e c a u s e d b y s e v e r a l r e s p o n s e s o f t h e n o n - e s t r o u s e w e s w h i c h b r e a k u p i n t e r a c t i o n s . T h e e w e d o e s t w o t h i n g s w h i c h s u b o r d i n a t e r a m s u s u a l l y d o n o t : ( a ) s h e w i t h d r a w s w h e n k i c k e d , ( b ) s h e u r i n a t e s t o t h e m a l e a n d h e p r o m p t l y l i p c u r l s . ( O c c a s i o n a l l y r a m s a l s o u r i n a t e t o a d o m i n a n t o n e , h o w e v e r , t h i s i s n o t a n e a s y b e h a v i o u r t o n o t e s i n c e t h e u r i n a t i o n p o s t u r e o f r a m s i s n o t c o n s p i c u o u s ) . L i p c u r l i n g i n t h e i n t e r a c t i o n s o f r a m s d o e s , h o w e v e r , o c c u r l e s s f r e q u e n t l y t h a n i n c o u r t s h i p s . B o t h o f 8 2 t h e s e d i f f e r e n c e s d i s a p p e a r w h e n t h e e w e i s i n e s t r o u s * T h u s d u r i n g 1 4 4 c o u r t s h i p s o n e s t r o u s e w e s , r a m s l i p c u r l e d o n l y 7 t i m e s , b u t i n c o u r t s h i p s o n n o n - e s t r o u s e w e s , t h e r a m s l i p c u r l e d 3 0 - 4 0 t i m e s p e r 1 0 0 c o u r t s h i p s ( P i g . 7 4 ) . F i g . 7 7 s h o w s t h e p e r c e n t f r e q u e n c y w i t h w h i c h t h e v a r i o u s s e x - a g e c l a s s e s w i t h d r e w f r o m t h e k i c k s a n d m o u n t s b y r a m s . I t c a n b e s e e n t h a t t h e e w e i n e s t r o u s w i t h d r e w a b o u t a s f r e q u e n t l y w h e n k i c k e d a s r a m s d i d . W h e n . n o t i n h e a t , e w e s w i t h d r e w m o r e t h a n t h r e e t i m e s a s f r e q u e n t l y w h e n k i c k e d a n d t w i c e a s f r e q u e n t l y w h e n m o u n t e d . T h e r e f o r e , w h e n t h e r a m k i c k s a n d t h e e w e r e m a i n s s t a n d i n g t h e " n o r m a l " b e h a v i o u r p e r f o r m e d b y a r a m t o w a r d s a s u b o r d i n a t e c a n p r o c e e d a n d t h e e w e g e t s m o u n t e d a f t e r a s e r i e s o f k i c k s . A s i n d i c a t e d a b o v e , t h e s e c o n d w a y t o i n t e r r u p t a r a m ' s c o u r t s h i p i s f o r t h e e w e t o u r i n a t e . N o v e m b e r a n d D e c e m b e r ( p r e - r u t a n d r u t ) e x c e p t e d , e w e s u r i n a t e d t o c o u r t i n g r a m s i n a b o u t 4 3 $ o f t h e c o u r t s h i p s , h o w e v e r , t h i s f i g u r e i s b a s e d o n a s m a l l s a m p l e ( n = 3 8 ) . I n N o v e m b e r , w h e n i n t e n s e l y c o u r t e d , S t o n e ' s e w e s u r i n a t e d d u r i n g 2 0 $ o f t h e c o u r t s h i p s ( n = 4 4 5 ) . D u r i n g D e c e m b e r r a m s s h i f t e d t h e i r a t t e n t i o n t o e s t r o u s e w e s a n d c o u r t e d n o n - e s t r o u s e w e s l e s s f r e q u e n t l y . N o w t h e p e r c e n t a g e o f c o u r t s h i p s i n w h i c h e w e s u r i n a t e d r o s e t o 3 6 ( n = 2 7 ) . A p p a r e n t l y t h e f r e q u e n c y o f u r i n a t i o n s i n c o u r t s h i p s i s i n v e r s e l y r e l a t e d t o t h e f r e q u e n c y w i t h w h i c h e w e s a r e c o u r t e d . 83 I f e w e s u r i n a t e o n t h e a p p r o a c h o f t h e r a m , t h a t i s , b e f o r e h e r e a c h e s t h e e w e , t h e c o u r t s h k p t e n d s t o b e v e r y s h o r t . T h u s , f o r 1 2 2 c o u r t s h i p s o n S t o n e ' s e w e s i n w h i c h u r i n a t i o n o c c u r r e d b e f o r e t h e r a m r e a c h e d t h e e w e , t h e a v e r a g e n u m b e r o f p a t t e r n s p e r f o r m e d b y t h e r a m o n o r t o w a r d s t h e e w e w a s 2 . 5 9 . H o w e v e r , i n 1 4 7 c o u r t s h i p s w h e r e t h e e w e u r i n a t e d a f t e r t h e r a m g o t t h e r e , t h e n u m b e r o f p a t t e r n s p e r i n t e r a c t i o n w a s 4 . 7 . B i g h o r n r a m s b e h a v e d s i m i l a r l y t o e w e s . I f e w e s u r i n a t e d b e f o r e t h e r a m g o t t h e r e , t h e l a t t e r p e r  f o r m e d 2 . 2 p a t t e r n s o n t h e a v e r a g e ( n = 1 4 ) ; i f t h e e w e u r i n a t e d a f t e r h e g o t t h e r e , t h e r a m p e r f o r m e d 4 . 9 p a t t e r n s o n t h e a v e r a g e . T h e r e f o r e , u r i n a t i o n b y t h e e w e a n d l i p c u r l i n g b y t h e r a m d o e s a p p e a r t o r e d u c e t h e b e h a v i o u r a l s e q u e n c e s i n c o u r t s h i p s . H o w e v e r , i t d o e s n o t a p p e a r t o m a t t e r i f t h e r a m l i p c u r l s o r n o t a f t e r t h e e w e u r i n a t e s f o r s u c h c o u r t s h i p s i n w h i c h r a m s l i p c u r l e d a r e j u s t a s l o n g a s t h o s e i n w h i c h r a m s d i d n o t . T h i s w a s t r u e b o t h f o r S t o n e ' s a n d f o r b i g h o r n e w e s . T h e f u n c t i o n o f l i p c u r l i n g a n d t h e a d a p t i v e s i g n i f i c a n c e o f t h e e w e ' s u r i n a t i o n r e s p o n s e r e m a i n u n k n o w n . L i n d s a y ( 1 9 5 5 ) s h o w e d t h a t r a m s d e p r i v e d o f t h e i r s e n s e o f s m e l l c o u l d n o t d i s t i n g u i s h e s t r o u s f r o m n o n - e s t r o u s e w e s . I n g e n e r a l , r a m s t r e a t e w e s a s i f t h e s e w e r e s u b  o r d i n a t e m a l e s . T h e y a r e , h o w e v e r , n o t a b l e t o p e r f o r m a s m a n y p a t t e r n s o n n o n - e s t r o u s e w e s b e c a u s e t h e y i n t e r r u p t t h e 8 4 i n t e r a c t i o n "by r u n n i n g a w a y w h e n k i c k e d , a n d / o r u r i n a t i n g w h i c h c a u s e s t h e r a m t o l i p c u r l a n d e n d t h e c o u r t s h i p . W h e n t h e e w e e n t e r s e s t r o u s , h e r h o r m o n a l c h a n g e s p r o b a b l y a r e r e s p o n s i b l e f o r e l i m i n a t i n g h e r w i t h d r a w a l r e s p o n s e t o t h e k i c k a s w e l l a s h e r u r i n a t i o n . N o w t h e b e h a v i o u r o f t h e e x c i t e d r a m t o w a r d s t h e e w e i s a l m o s t i d e n t i c a l t o t h a t o f e x c i t e d r a m s t o o n e a n o t h e r w h e n t h e y p e r c e i v e b u t a r e b a r r e d f r o m t h e e s t r o u s e w e . F u r t h e r m o r e , t h e e w e a c t s n o t o n l y l i k e a r a m b y a c c e p t i n g f r o n t - k i c k s w i t h o u t r e s p o n d i n g , b u t s h e a l s o b e h a v e s v e r y s i m i l a r l y t o a s u b o r d i n a t e r a m - s o m e t h i n g s h e d o e s o n l y w h e n i n h e a t . C o n v e r s e l y , s m a l l r a m s m a y b e h a v e l i k e e w e s b y u r i n a t i n g t o d o m i n a n t r a m s o r p e r f o r m i n g l o r d o s i s w h e n m o u n t e d ( F i g . 4 4 ) . 85 PART I I I DESCRIPTION OP SHEEP BEHAVIOUR DURING EARLY WINTER Normal d a i l y behaviour of rams Before some of the unique f e a t u r e s of ram s o c i e t y can be a p p r e c i a t e d , one needs to know something of t h e i r normal d a i l y behaviour. Rams spend most of the day f e e d i n g and r e s t i n g . Stone's rams were a c t i v e d u r i n g 65$ of the d a y l i g h t hours i n October (n = 93 hours) and 58$ i n February (n • 114 h o u r s ) . Rams f e e d about 75 - 80$ of the time they are a c t i v e and o n l y a s m a l l f r a c t i o n of the day i s devoted t o s o c i a l i n t e r a c t i o n s . During f e e d i n g rams ten d to be d i s p e r s e d ( F i g . 7 8 ) . F e e d i n g p e r i o d s are i n t e r s p e r s e d w i t h r e s t i n g p e r i o d , d u r i n g which rams tend to r e s t t o g e t h e r . Before a r e s t i n g or f e e d i n g p e r i o d , rams f r e q u e n t l y engage i n minor i n t e r a c t i o n s . P a r t i c u l a r l y rams of n e a r l y the same dominance rank i n t e r a c t q u i t e r e g u l a r l y a t t h i s time. O c c a s i o n a l l y a l a r g e ram d i s p l a c e s a s m a l l e r one from a bedding s i t e . D uring the r e s t i n g p e r i o d a ram p e r i o d i c a l l y gets up, u r i n a t e s and d e f e c a t e s and then t u r n s and l i e s down a g a i n . A l o t o f u r i n e and f e c e s are d e p o s i t e d on the r e g u l a r bedding s i t e s and i n s p r i n g the grass i s u s u a l l y greener and grows l o n g e r at the edge o f , and below, sheep beds. 86 When d u r i n g a minor move rams stop t e m p o r a r i l y as a group, small rams ten d to n i b b l e and rub t h e i r noses on the horns of l a r g e r rams. Du r i n g l o n g marches sheep u s u a l l y move i n s i n g l e f i l e , w ith a l a r g e horned ram l e a d i n g ram bands and an a d u l t ewe l e a d i n g ewe bands. The r u l e t h a t the l a r g e s t horned ram l e a d s , was broken on l y twice from 73 i n s t a n c e s . In both cases the band was f o l l o w i n g a l a r g e c l a s s I I I ram w h i l e a IV ram was present (Table I I I ) . Ram bands mix w i t h a minimum of s t r i f e ; sheep l i v e i n an open s o c i e t y . A group of t h r e e rams which i s moving t o another group i n s i n g l e f i l e , i s shown i n F i g . 79. Note t h a t the l e a d i n g c l a s s IV ram i s e n t e r i n g the new group i n a horn d i s p l a y , a behaviour f r e q u e n t l y shown by sheep e n t e r  i n g a group or p a s s i n g an i n d i v i d u a l . Only when rams of equal s i z e meet, and have not seen each other f o r months, i s t h e r e a good chance of o b s e r v i n g a le n g t h y i n t e r a c t i o n between them. T h i s i s not a common occurrence, however, Group i n t e r a c t i o n s Mountain sheep d i f f e r from other North American ruminants i n t h a t males perform group i n t e r a c t i o n s . The s i m p l e s t form I termed a "huddle". A l l , or most, rams from a group gather i n t o a t i g h t bunch on a l e v e l spot on top of a r i d g e or on some l e v e l a r e a on a s l o p e . They f a c e the c e n t r e of the g a t h e r i n g , t h e i r white rumps f a c i n g out ( F i g . 80). 87 The l a r g e r rams d i s p l a y w h i l e the younger ones rub and horn the l a r g e r ones. P e r i o d i c a l l y the huddle may erupt i n t o threat-jumping, clashing rams which f r e e z e i n t o r i g i d present a f t e r the l a s t c l a s h , and then c l o s e i n f o r more d i s p l a y and co n t a c t behaviour. The f r o n t - k i c k i s r a r e l y seen i n huddles; mounting occurs o c c a s i o n a l l y . I t i s o n l y i n huddles t h a t I observed s m a l l e r rams mount l a r g e r ones. Huddles were observed throughout the year, but p r i m a r i l y i n f a l l , s p r i n g and e a r l y summer. They are most f r e q u e n t l y seen i n the morning and l a t e a f t e r n o o n . In the dense p o p u l a t i o n s of bighorns and D a l l ' s sheep which I s t u d i e d , huddles were common, but among my Stone's sheep they were r a r e . A r a r e form o f the huddle i s the " r a p i n g p a r t y " . A group of rams focuses i t s a t t e n t i o n on one c l a s s I ram and begins mounting him. The l i t t l e ram i s c o u r t e d u n t i l he runs away. I observed o n l y f o u r r a p i n g p a r t i e s and these soon disappeared from s i g h t . Groups of p l a y i n g rams are more commonly seen i n s p r i n g and summer than at ot h e r seasons. I t may b e g i n when rams huddle a f t e r r i s i n g i n the morning and are s t i l l i n the c l i f f s above the s l o p e s . One ram t u r n s from the group, shakes h i s head and begins t o bounce d o w n h i l l . Others f o l l o w and b e g i n t o f r o l i c . Suddenly the l e a d ram w h i r l s , t h r e a t - jumps and o f t e n c l a s h e s on the ram be h i n d him ( P i g . 8 1 ). Both 88 may f r e e z e i n p r e s e n t . Others h u r r y to them forming another temporary huddle u n t i l one ram runs away. During such runs, rams may w h i r l about, threat-jump r e p e a t e d l y , bound h i g h i n t o the a i r , cut other rams o f f or c l a s h i n s e r i e s w i t h s e v e r a l rams ( F i g . 82)• I have seen as many as e i g h t rams s t a n d i n g i n a c i r c l e on t h e i r h i n d l e g s , f a c i n g each o t h e r . I soon found t h a t p l a y i n g c o u l d be a r t i f i c a l l y p r o  voked as l o n g as I c o u l d get rams to run downhill towards me. T h i s was not d i f f i c u l t to do s i n c e the rams were eager to l i c k the s a l t I always c a r r i e d f o r them. The f u n c t i o n of group i n t e r a c t i o n s appears to be s t a b i l i z a t i o n of dominance r e l a t i o n s h i p s . When h u d d l i n g , rams can meet and engage i n s o c i a l i n t e r a c t i o n s which l a c k the tenseness of dominance f i g h t s . They can acquaint them s e l v e s w i t h the f i g h t i n g p o t e n t i a l of o t h e r members of the band, and are s t e a d i l y reminded of i t d u r i n g f r e q u e n t h u d d l e s . I t may a l s o be t h a t s m a l l rams c o n t i n u o u s l y impregnate them s e l v e s w i t h the s e c r e t i o n from the p r e o r b i t a l g l a n d of l a r g e r rams, and a c q u i r e a group s c e n t . The s i g n i f i c a n c e of t h i s i s not c l e a r except t h a t i t would c o n t r i b u t e t o making the s o c i a l environment f a m i l i a r and p r e d i c t a b l e . Huddles appear t o be a l e s s w a s t e f u l way of s t a b i l i z i n g dominance rank than dominance f i g h t s ; on the Stone's sheep study area I saw few huddles and almost a l l dominance f i g h t s while f o r the b i g h o r n and D a l l sheep I observed the converse was t r u e . 89 Some group i n t e r a c t i o n s r e s u l t when a t h i r d ram e n t e r s i n t o a c o n f l i c t between two rams. I observed o n l y once a l a r g e r ram ( I I I ) , b r e a k i n g up a dominance f i g h t between two s m a l l e r rams ( I I ) by a t t a c k i n g the l a r g e r . D u r i n g a dominance f i g h t between two bighorn rams ( c l a s s I V ) , a s m a l l e r ram ( I I I ) r e g u l a r l y c l a s h e d i n t o the s i d e of the l a r g e r each time the two l a r g e r rams c l a s h e d . The s m a l l e r ram was p i r a t i n g s o c i a l advantage from an animal i t would not n o r m a l l y a t t a c k . The l a r g e r ram c o u l d not r e t a l i a t e s i n c e h i s l a r g e opponent would have smashed a t once i n t o h i s s i d e . Every time the l a r g e IV ram t u r n e d to the I I I ram, h i s c l a s s IV opponent made i n t e n t i o n movements to c l a s h and the IV ram t u r n e d away from h i s s m a l l e r opponent. I t i s not uncommon to see a s m a l l ram e n t e r i n t o an i n t e r a c t i o n between two l a r g e r rams and b e g i n to horn and b u t t the second l a r g e s t . In one o t h e r i n s t a n c e , the subordinate of two i n t e r a c t i n g rams searched out h i s next subordinate and assumed p o s i t i o n behind him. T h i s r e s u l t e d i n t h r e e rams s t a n d i n g one behind the o t h e r . When the l a r g e s t k i c k e d , the second l a r g e s t passed on the k i c k t o the t h i r d and s m a l l e s t ram. Twice I observed two rams "gang-up" on a t h i r d , and f i l m e d one of these i n t e r  a c t i o n s . One of these rams was a s m a l l f o u r year o l d who was strange to the area and was c o n f r o n t e d by two s l i g h t l y l a r g e r rams. The rams c l a s h e d and horned w i t h each other and on one o c c a s i o n the s m a l l e r was pushed s i m u l t a n e o u s l y from the f r o n t and r e a r by the two l a r g e r ones. 90 Dominance f i g h t s I observed dominance f i g h t s o n l y between rams o f equal or near equal horn and body s i z e . Such f i g h t s can occur at any time of the year but seem most fre q u e n t d u r i n g seasonal m i g r a t i o n s when s t r a i n g e rams are most l i k e l y to meet. F o r one of the c o n d i t i o n s of dominance f i g h t s i s t h a t the p a r t n e r s a re s t r a n g e r s or have not seen each other f o r s e v e r a l months. I have argued p r e v i o u s l y t h a t rams appear to r e c o g n i z e each other's dominance rank by t h e i r horn s i z e s ( G e i s t , 1966). Hence smal l horned rams l a r g e l y i g n o r e a l a r g e r horned s t r a n g e r , or a c t towards them at once as s u b o r d i n a t e s . When rams of equal horn s i z e meet, th e r e i s no c r i t e r i o n whereby dominance c o u l d be s e t t l e d a p r i o r i , and only a f i g h t can determine i t . However, dominance f i g h t s are q u i t e r a r e . The l o n g e s t dominance f i g h t I observed o c c u r r e d on March 19 and 20, 1962, between two seven year o l d Stone's rams, G and M, both c a r r y i n g f c u r l h o r ns. S i n c e these rams showed almost a l l the p o s s i b l e combat phases, and no other dominance f i g h t I ever witness added much t h a t was new, I s h a l l c oncentrate on t h i s i n t e r a c t i o n . G-ram was a r e s i d e n t o f Sanctuary Mountain. M-ram c r o s s e d w i t h the l a r g e r F-ram ( c l a s s IV) to Sanctuary on the morning of March 18th. M and F-ram d i d not meet the Sanctuary rams however, t i l l about 10 a.m. of the 19th. F-ram, who was 91 o n l y seven years o l d ( l i k e M and G) but c a r r i e d much l a r g e r horns i n t e r a c t e d s h o r t l y with d i s p l a y p a t t e r n s with two c l a s s IV Sanctuary rams of s l i g h t l y s m a l l e r horn s i z e , and emerged as the dominant without any f i g h t . Then G-ram came i n l o w - s t r e t c h to F, and k i c k e d a t h i s r e a r . F-ram w h i r l e d and rose i n t o a threat-jump at which G-ram turned and moved o f f . G-ram co n t i n u e d i n l o w - s t r e t c h s t r a i g h t at the s l i g h t l y l a r g e r M-ram and k i c k e d him on the c h e s t . Both rams then s t o o d shoulder t o shoulder, d i s p l a y e d i n present and k i c k e d at each o t h e r ' s chest and b e l l y . Thus a t 10.10 a.m. began an i n t e r a c t i o n which was to continue f o r 25 hours. The behaviour of rams i n a dominance f i g h t can be d i v i d e d i n t o s e v e r a l c a t e g o r i e s which are i l l u s t r a t e d i n F i g . 8 3 . One engagement c y c l e goes approximately as f o l l o w s : one ram approaches the other i n l o w - s t r e t c h , t w i s t i n g h i s horns and g r u n t i n g ( F i g . 8 3 A ) , and d e l i v e r s a k i c k a t the opponent's c h e s t . T h i s begins the k i c k phase i n which rams s t a r t out s t a n d i n g shoulder to shoulder, but while exchanging k i c k s , s l i d e a l o n g each other's s i d e ( F i g . 83B ). Both opponents d i s p l a y i n present and growl on each k i c k . O c c a s i o n a l l y one d i g s h i s horn i n t o h i s opponent's back or b u t t s sideways at h i s p a r t n e r ' s head. The rams may push wi t h the shoulders or chest a t each other, which may l e a d t o some c i r c l i n g or w h i r l i n g s h o u lder to shoulder about each o t h e r . The kick-phase may l a s t f o r only one k i c k but may run t o 4 3 k i c k s . Rams tend t o f 92 r e p l y to k i c k s i n a t i t - f o r - t a t f a s h i o n . Bighorns d i f f e r e d from Stone's rams i n th a t they coupled some k i c k s w i t h a b u t t a t the opponent. The kick-phase ends when one or both suddenly p u l l t h e i r heads down i n t o a l o w - s t r e t c h and move past the oth e r ( F i g . 83C). Sometimes one breaks o f f the k i c k phase by t u r n i n g i n l o w - s t r e t c h r i g h t around while p r e s s i n g h i s r e a r a g a i n s t h i s opponent's s i d e . A f t e r both walk away s e v e r a l s t e p s , b o t h w h i r l around and r i s e on t h e i r h i n d l e g s i n t o a threat-jump ( F i g . 83D). T h i s may l e a d at once t o a c l a s h ( F i g . 83E) or both rams drop down and f r e e z e i n t o a present ( F i g . 83F). The present a l s o f o l l o w s the c l a s h . The rams may break o f f here and f e e d s i d e by s i d e ( F i g . 83G) or again i n i t i a t e ( F i g . 834) and be g i n once more. From the 25 hours which M and G fought, I o b t a i n e d e x a c t l y 8 hours of q u a n t i t a t i v e d a t a . In t h a t time I r e  corded 92 k i c k phases; 36 of these were f o l l o w e d by a t h r e a t - jump, present and ended at t h a t p o i n t on 20 (from 36) occa s i o n s ; 17 k i c k phases were f o l l o w e d by a c l a s h - present and o n l y 3 ended a t t h a t p o i n t . T h e r e f o r e , 30 k i c k phases f o l l o w e d at once a f t e r a threat-jump or c l a s h and 62 k i c k phases were n o n - c y c l i c . 39 k i c k phases ended by both rams moving apart and b e g i n n i n g to f e e d . When not engaged both rams u s u a l l y f e d s i d e by s i d e c a r e f u l l y watching each o t h e r . Suddenly one or the other would j e r k up h i s head, at which the oth e r a l s o j e r k e d up or rose i n t o a threat-jump. I kept note of how such s h o r t 93 f e e d i n g p e r i o d s ended. On 38 o c c a s i o n s both rams j e r k e d t h e i r heads up and f r o z e i n t o a present d i s p l a y . In 23 i n s t a n c e s the rams suddenly rose and c l a s h e d , hence, a l i t t l e more than h a l f of a l l c l a s h e s observed were these sudden engagements t e r m i n a t i n g a f e e d i n g p e r i o d . In 15 i n s t a n c e s the rams only threat-jumped and f r o z e then i n present, and on two occasions one suddenly b u t t e d the other and both en gaged. From these 78 f e e d i n g p e r i o d endings, 64 l e d on t o f u l l engagements and k i c k phases, and on 14 the rams r e t u r n e d t o f e e d a g a i n . In the b e g i n n i n g of t h e i r engagement M and G-rams horned the ground or small a l p i n e f i r s e x t e n s i v e l y . In t h e i r f i r s t hour they horned 4 times, i n the second 20, i n the t h i r d 16, i n the f o u r t h 4, a f t e r t h a t h o r n i n g v a r i e d between 1 and 6 per hour. On the morning of the 20th the two t i r e d rams had almost stopped h o r n i n g . T h i s d i s t r i b u t i o n of h o r n i n g supports the h y p o t h e s i s t h a t i t i s a s i g n of excitement r a t h e r than a s o c i a l l y meaningful p a t t e r n . M- and G-ram horned e q u a l l y f r e q u e n t l y . M and G d i d not b u t t each o t h e r as f r e q u e n t l y d u r i n g the f i r s t few hours of the f i g h t as l a t e r . In the f i r s t 4^ hours o f the engagement the rams exchanged two b u t t s , but i n the next 3^ hours they b u t t e d each other 27 t i m e s . Now one began; t o n o t i c e t h a t the rams were ba d l y s t r a i n e d and they began t o loo k t i r e d . I observed how one or both staggered 94 to r e g a i n f o o t i n g a f t e r a heavy c l a s h . In some c l a s h e s i t appeared as i f t h e i r horns s l i p p e d o f f each other, f o r one would l i t e r a l l y p i l e up i n f r o n t of the l e g s of the o t h e r . O c c a s i o n a l l y one climbed up and c l a s h e d almost s t r a i g h t down. N e i t h e r l o s t i t s f o o t i n g i n such c l a s h e s . Only once d i d they hook horns and b e g i n a s h o r t but v i o l e n t s t r u g g l e . I ended o b s e r v a t i o n s a t 18.50 hours at dusk. Dur i n g the n i g h t I heard c l a s h e s , i n d i c a t i n g t h a t M and G were s t i l l engaged. In the e a r l y morning I found M and G r e s t i n g o p p o s i t e each other, s t i l l d i s p l a y i n g s t i f f l y i n present to each o t h e r . At 9.00 a.m., I heard the f i r s t c l a s h of the morning and r e t u r n e d t o observe them. At 10.20 a.m. the l a s t c l a s h f e l l . J u s t p r i o r t o i t , G-ram had e n t e r e d i n t o almost v i o l e n t kick-phases t o which M-ram h a r d l y r e p l i e d . I t appeared as i f G-ram was d e s p e r a t e l y a c t i n g as a dominant. Both rams f e d on s t e a d i l y . At 12.15 p.m., M-ram w h i r l e d towards G, then f r o z e i n p r e s e n t , but G d i d not f l i n c h and f e d on. At 12.25 p.m., M-ram came t o G i n l o w - s t r e t c h and began k i c k i n g but G t u r n e d h i s r e a r on M while f e e d i n g . From then on he d i d not r e p l y t o any of M?s k i c k i n g , d i s p l a y s , or threat-jumps. The f i g h t was o v e r . The dominance had been s e t t l e d . G-ram had l o s t f o r he now accepted b e i n g d i s p l a y e d to and behaved l i k e a ewe by not r e p l y i n g . 95 One behaviour p a t t e r n which M and G d i d not show i n t h e i r f i g h t , but which some other Stone's rams showed was pawing the ground d u r i n g the engagement. In some dominance f i g h t s , t h i s f o l l o w e d a f t e r rams disengaged from the k i c k - p h a s e . The ram pawed the ground 3 - 4 times b e f o r e or a f t e r t u r n i n g and f a c i n g the opponent i n l o w - s t r e t c h . Pawing was, however, r a r e . I saw o n l y Stone's sheep do i t . However, Jones (1950) c i t e d an o b s e r v a t i o n of Griggs, who saw pawing by desert b i g h o r n rams d u r i n g combat. Walther (1961) r e p o r t e d t h a t a c a p t i v e Marco P o l o ram (0 . ammon p o l i ) pawed exub e r a n t l y p r i o r t o threat-jumps i n engagements wi t h an u r i a l ( 0 . ammon c y c l o c e r o s ) or a g a i n s t the ob s e r v e r . In American sheep t h i s behaviour p a t t e r n may be v e s t i g i a l . The opponents i n a dominance f i g h t do not n e c e s s a r i l y separate once the f i g h t i s over. M-ram f o l l o w e d G about on the 20th but d i d not search him out l a t e r . A f t e r a dominance f i g h t one c l a s s I I ram f o l l o w e d and engaged on another f o r at l e a s t 3 days a f t e r the i n i t i a l engagement. Some dominance f i g h t s may r e s u l t i n the f o r m a t i o n o f "dominance p a i r s " i n which the l a r g e r s t e a d i l y f o l l o w s the s m a l l e r ram and the two remain t o g e t h e r f o r months. The post f i g h t i n g phase i s c h a r a c t e r i s e d by the sub o r d i n a t e s acceptance o f what amounts to i n s u l t . I observed the dominant p a r t n e r not o n l y d i s p l a y t o the subordinate, k i c k and mount him, but a l s o move d i r e c t l y i n f r o n t of him, loo k s q u a r e l y at him then threat-jump r e p e a t e d l y . Normally, 96 I would expect t h a t , a t t h i s , the subordinate would at once c l a s h h e a v i l y i n t o the dominant. However, a f t e r a dominance f i g h t , the subordinates kept on f e e d i n g and s l o w l y t u r n e d t h e i r r e a r t o the opponent. Regardless of what the dominant d i d they f e d q u i e t l y on, and o r i e n t e d away from him. I t may be t h a t t u r n i n g the rump patch t o the opponent some how appeased i t . In t o t a l I saw s i x dominance f i g h t s among Stone's sheep and p a r t of a seventh one. Three took p l a c e i n s p r i n g , one i n l a t e summer, and t h r e e i n the p r e - r u t . I saw only one, v e r y s h o r t dominance f i g h t between two c l a s s I I D a l l rams which was l a c k i n g i n v i g o u r and the r i c h n e s s of d e t a i l the Stone's sheep showed. Among bigh o r n s I saw not a s i n g l e i n t e n s e f i g h t , but d i d observe s e v e r a l p o o r l y r i t u a l i s e d engagements which were dominance f i g h t s of s o r t s . None l a s t e d long; the same two rams mainly c l a s h e d now and again then dropped i n t o a s t i f f present and soon f e d on. These d i f f e r e n c e s between sheep on my Stone's, D a l l , and b i g h o r n study areas are almost c e r t a i n l y p o p u l a t i o n and not s p e c i e s d i f f e r e n c e s . The D a l l and b i g h o r n p o p u l a t i o n s were both q u i t e dense and the i n d i v i d u a l s a c t e d much more a l i k e than d i d the Stone's sheep. I noted e a r l i e r t h a t huddles on the Stone's sheep area were r a r e , but very common among the D a l l and b i g h o r n sheep observed. I t may be t h a t huddles are a s i m p l e r manner o f e s t a b l i s h i n g dominance orders where sheep 97 are very common and strange i n d i v i d u a l s meet f r e q u e n t l y . There were few sheep on my Stone's sheep a r e a . Dominance f i g h t s between ewes do occur but must be r a r e . In 42 months i n the f i e l d w i t h sheep, I observed o n l y one. I t was a s h o r t f i g h t between two b i g h o r n ewes on October 31, 1964. Three females s t o o d i n a group on a rddge. Two ewes are p r i m a r i l y engaged. The subordinate ewe b u t t e d the dominant one 5 times, c l a s h e d 4 times on her, and n i b b l e d h e r head q u i t e e x t e n s i v e l y t w i c e . She r e c e i v e d one c l a s h and a weak h o r n - t h r e a t i n r e t u r n . The t h i r d ewe c l a s h e d twice on the s u b o r d i n a t e ewe and mounted the dominant once. I t appeared, as i n some ram i n t e r a c t i o n s , t h a t a t h i r d animal was t a k i n g advantage of one, or both, f i g h t i n g i n d i v i d u a l s . 4s i n ram i n t e r a c t i o n s , the dominant i s the one who can stand and accept the a g g r e s s i v e behaviour (as d i s t i n c t from c o u r t s h i p behaviour) of the s u b o r i n a t e w i t h l i t t l e or no r e p l y . 4 f u r t h e r r e p o r t on what appeared t o be a dominance f i g h t of ewes i s found i n B l o o d (1963). 4 t p resent a comparison of dominance f i g h t s between d i f f e r e n t r a c e s of North American sheep cannot go v e r y f a r . Good d e s c r i p t i o n s of f i g h t i n g D a l l rams are l a c k i n g . The c a r e f u l o b s e r v a t i o n s of Welles and Welles (1961) and t h e i r e x c e l l e n t photography of dominance f i g h t s among de s e r t sheep (jQ» J3 . n e l s o n i ) i n d i c a t e t h a t Stone's and b i g h o r n sheep d i f f e r o n l y s l i g h t l y . Stone's sheep paw a l i t t l e d u r i n g dominance 98 f i g h t s , bighorns very r a r e l y ; b ighorns use the horn jab i n t o the opponent's back f r e q u e n t l y , Stone's sheep r a r e l y . Bighorns combine the k i c k and a b u t t which Stone's sheep do very r a r e l y . In g e n e r a l , i t appears t h a t bighorns b u t t and c l a s h more f r e q u e n t l y and are g e n e r a l l y rougher than t h i n - h o r n sheep (see T a b l e IV) U n r i t u a l i s e d f i g h t i n g V i c i o u s , u n r i t u a l i s e d f i g h t s occur between rams about an e s t r o u s ewe, but may be induced by p r o v i d i n g o n l y l i m i t e d access t o a p i e c e of s a l t . I have observed and f i l m e d a number o f u n r i t u a l i s e d brawls i n the l a t t e r s i t u a  t i o n , and have found them no l e s s f i e r c e than those about e s t r o u s ewes. The v i c i o u s f i g h t s o f rams are s l u g g i n g and w r e s t l i n g matches of b r u t e f o r c e , l a c k i n g a l l r i t u a l and f i n e s s e . Rams w h i r l about one another, t r y i n g t o keep t h e i r horns p o i n t e d a t the opponent as a defense measure, and t r y to c r a s h i n t o the opponent's s i d e whenever p o s s i b l e . Rams h i t out sideways w i t h t h e i r heads ( F i g . 84),Jpush each other around w i t h chest and shoulders ( F i g . 85), and b u t t each other wherever p o s s i b l e w h i l s t t r y i n g t o a v o i d the blows of the o t h e r . O c c a s i o n a l l y , horns get l o c k e d ( F i g . 86) and rams may t u g and w r e s t l e or b l i n d l y w h i r l around each other, a p p a r e n t l y i n an attempt to f r e e themselves. The f i g h t i s ended when one of the opponents f l e e s w h i le the o t h e r charges head lowered a f t e r him. 99 In the defense o f an e s t r o u s ewe, a l a r g e Stone's ram slammed a c l a s s I I ram i n t o the snow wit h a blow to i t s s i d e . But the s m a l l ram r e c o v e r e d q u i c k l y . In another f i g h t about an e s t r o u s ewe, the defending l a r g e c l a s s I¥ b i g h o r n ram stumbled and f e l l i n t o a snowbank. At once the next l a r g e s t , a c l a s s I I I ram pounced on him and, u s i n g i t s horns, h e l d the s t r u g g l i n g f u l l c u r l h e l p l e s s on i t s s i d e . I saw Stone's rams t r y i n g r e p e a t e d l y t o push s m a l l e r rams o f f a c l i f f d u r i n g the defense of a ewe. I saw t h i s o n l y at t h a t time among rams, but d i d see a 2 year o l d female t r y i n g t o push a y e a r l i n g ram o f f a c l i f f f a c e . In a l l i n s t a n c e s the sheep jumped t o a lower l e d g e . The v i c i o u s f i g h t s o f rams have l i t t l e i n common with dominance f i g h t s . Y e a r l i n g rams g a i n dominance over ewes When i n October, 1961 and 1962 Stone's sheep were r e t u r n i n g t o the study a r e a , i t was n o t i c e a b l e t h a t y e a r l i n g rams (17 months old) were f r e q u e n t l y e n t e r i n g i n t o dominance i n t e r a c t i o n s w i t h ewes. At f i r s t y e a r l i n g and two year o l d ewes were the main t a r g e t , then a d u l t ewes. The same be ha v i o u r was s t r i k i n g l y n o t i c e a b l e among D a l l sheep a t Kluane Lake, but I d i d not observe i t t o the same extent i n f a l l , 1964, among bighorns i n Banff Park. T h i s i s probably due to the poor grox^th of bi g h o r n y e a r l i n g s on my study area, which a t 18 months o f age b a r e l y reached female s i z e , had small t e s t e s and d i d not en t e r i n t o the r u t . On the oth e r 1 0 0 h a n d , y e a r l i n g s o n t h e S t o n e ' s s h e e p a n d D a l l s t u d y a r e a r e a c h e d f e m a l e s i z e b e f o r e t h e r u t , a n d h a d c l e a r l y v i s i b l e , l a r g e t e s t e s . T h e S t o n e ' s y e a r l i n g s w e r e v e r y i n t e r e s t e d i n e s t r o u s e w e s a n d l i p c u r l e d o v e r f e m a l e u r i n e ( t h i s a p p e a r s t o b e a s i g n o f s e x u a l m a t u r i t y ) . A m o n g t h e S t o n e ' s s h e e p o b s e r v e d , a l l y e a r l i n g m a l e s d o m i n a t e d f e m a l e s b y 1 8 m o n t h s o f a g e , s o m e b i g h o r n r a m s d i d n o t m a n a g e t o d o t h i s u n t i l 2 8 - 3 0 m o n t h s o f a g e f o r e w e s w e r e o c c a s i o n a l l y s u c c e s s f u l i n d r i v i n g Z\ y e a r o l d r a m s f r o m s o m e s a l t . A l r e a d y a t 1 1 - 1 2 m o n t h s o f a g e , r a m s b e g i n t o p e s t e r y e a r l i n g e w e s a r e v e n s m a l l t w o y e a r o l d e w e s , b y s t a n d i n g b e h i n d t h e m , s u d d e n l y m o u n t i n g , b u t t i n g , n u d g i n g o r d i s p l a y i n g t o t h e m ( F i g s . 8 7 & 8 8 ) . T h e l o w - s t r e t c h i s s t i l l u s e d v e r y r a r e l y a t t h a t a g e , b u t b e c o m e s m o r e c o m m o n t o w a r d f a l l , a l t h o u g h s t i l l n o t a s f r e q u e n t a s u s e d b y o l d e r r a m s ( F i g . 7 4 ) . T h e s m a l l e w e s u s u a l l y w i t h d r a w , b u t o c c a s i o n a l l y u r i n a t e t o t h e y e a r l i n g o r b u t t h i m . I n f a l l , f e m a l e s a r e m o s t a n t a g o n i s t i c t o t h e y e a r l i n g r a m s . I n a n u m b e r o f i n s t a n c e s i t c o m e s t o s h o r t b u t f i e r c e f i g h t s b e t w e e n t h e m ( F i g . 8 9 ) . D o m i n a n c e i s r e v e a l e d w h e n t h e r a m c a n i n  s p e c t , k i c k o r m o u n t t h e e w e s w i t h o u t p r e c i p i t a t i n g a f i g h t o r b e i n g c h a s e d a w a y . G e n e r a l l y , e w e s a r e c o n s i d e r a b l y m o r e a n t a g o n i s t i c t o t h i s c l a s s t h a n t o l a r g e r r a m s . E w e s i n i t i a t e i n t e r a c t i o n s o n y e a r l i n g r a m s f r e q u e n t l y ( F i g . 6 7 ) a n d t h e y r e p l y t o t h e i r i n t e r a c t i o n s m o r e f r e q u e n t l y ( F i g . 7 4 B ) . I n 101 l a t e f a l l , o c c a s i o n a l l y a y e a r l i n g ram pursued, herded and r e p e a t e d l y charged and h u t t e d a female as i f e n j o y i n g the l i c e n s e o f hard-won dominance. The p r e - r u t In l a t e October and e a r l y November, rams on a l l t h r e e study areas began t o appear on the ewe ranges and a s s o c i a t e d f a i r l y s t e a d i l y w i t h ewes. Strange rams meeting each o t h e r entered i n t o i n t e r a c t i o n s , only very few o f which were dominance f i g h t s . Rams became i n c r e a s i n g l y more a c t i v e . In October they were a c t i v e about 65$ o f the d a y l i g h t hours (n = 93 h o u r s ) , i n the f i r s t h a l f of November 67$ (n = 60 h o u r s ) , i n the second h a l f of November 73$ (n = 64 h o u r s ) , i n December 83$ (n = 68 h o u r s ) , i n January 71$ (n = 98 h o u r s ) , i n February 58$ (n = 114 h o u r s ) . O v e r a l l a c t i v i t y i n c r e a s e d t o r e a c h a maximum d u r i n g the r u t and subs i d e d i n the f o l l o w  i n g months. Rams cou r t the non-estrous ewes. Young rams i n p a r t i c u l a r show: some behaviour which d e v i a t e s from the c o u r t  s h i p s d e s c r i b e d so f a r . Young rams ten d t o mount ewes much more f r e q u e n t l y than o l d e r rams ( F i g . 102). A f t e r s n i f f i n g the ewe, they suddenly attempt t o mount w i t h e r e c t e d pro t r u d i n g p e n i s . The ewes v i r t u a l l y always attempt t o j e r k f r e e . The o n l y exceptions observed were s e v e r a l 2^ year o l d females t h a t had reached sexual m a t u r i t y . They accepted some mountings when not i n e s t r o u s . 102 On the Stone's sheep area, I observed a few young rams guarding non-estrous ewes d u r i n g each r u t t i n g season. The o b j e c t of such appeared to be to prevent the ewe from g o i n g anywhere. The moment she moved, the ram pounced i n h e r way and i n h o r n - t h r e a t chased h e r back. The ram c o u l d be p o s i t i o n e d below or above the ewe. He d i d not f e e d but s t o o d and watched h e r . A. few times guarded ewes attempted t o break out and the rams gave chase. In o n l y one i n s t a n c e d i d the ewe manage t o escape and j o i n the ewe group. U s u a l l y the ram got i n f r o n t o f h e r and cut her o f f . Guarding rams which stood above the ewe descended s t e a d i l y i n e l e v a t i o n w h i l e those below a guarded ewe s t e a d i l y ascended, s i n c e i n every short chase the former ram chased the ewe down and the l a t t e r chased h e r up. The l a r g e s t ram I observed guarding a s i n g l e non-estrous ewe was a c l a s s I I I Stone's ram. I observed o n l y one 5 year o l d c l a s s I I Stone's ram g u a r d i n g a non-estrous ewe and defending her as i f she was i n e s t r o u s a g a i n s t another 5 year o l d ram and a 3 year o l d . On t h r e e s u c c e s s i v e days i n December, 1965, I checked on t h i s group and noted t h a t the guarding young ram d i d not f e e d , r e s t e d very l i t t l e , and prevented o t h e r small rams from r e a c h i n g the group he guarded - an a d u l t ewe w i t h lamb, p l u s a 2^ year o l d ewe r e a c h i n g sexual m a t u r i t y . I must s t r e s s here t h a t h i s behaviour i s h i g h l y e x c e p t i o n a l , f o r rams norm a l l y guard o n l y e s t r o u s ewes. 103 Durin g the p r e - r u t , rams f r e q u e n t l y moved alone between groups of females or wandered over the r u t t i n g r anges. These s e a r c h i n g rams moved t o p r o j e c t i n g rock outcroppings and f r e q u e n t l y stood and scanned the s l o p e s and c l i f f s about them. S e a r c h i n g rams move n o r m a l l y at a walk a l o n g e s t a b l i s h e d t r a i l s , s t o p p i n g here and t h e r e t o scan the c o u n t r y s i d e or s n i f f and l i p c u r l over a u r i n e s p o t . They l i c k t h e i r l i p s f r e q u e n t l y when moving, and now and ag a i n c a l l w i t h a deep, l o u d "baa". D a l l rams appear t o have a h i g h e r v o i c e than b i g h o r n s . Wandering rams descend t o groups o f females or rams i n l o w - s t r e t c h and be g i n s o c i a l i n t e r a c t i o n s . A f t e r I got t o know the r u t t i n g ranges of Stone's sheep, I n o t i c e d t h a t s e a r c h i n g rams s y s t e m a t i c a l l y v i s i t e d and lo o k e d over the l o c a l i t i e s f a v o u r e d by sheep. P e r i o d i c a l l y a young ram showed an extended i n t e r e s t i n one ewe and p e r s i s t e n t l y c o u r t e d the uncooperative female. In a few i n s t a n c e s I observed such a ram stand s e v e r a l paces be h i n d the female and while l o w - s t r e t c h i n g , and t w i s t i n g , perform a f r o n t - k i c k i n t o the a i r . The young ram p e r s i s t e d i n h i s e f f o r t s but remained a t a d i s t a n c e , p e r i o d i c a l l y advancing 2 - 3 st e p s , t w i s t i n g , tongue f l i c k e r i n g and g r u n t i n g and then p u l l i n g back 2 - 3 steps t o assume the p r e v i o u s p o s i t i o n ( F i g . 4 0 ) . He k i c k e d r a r e l y . With each t w i s t - g r o w l approach the ewe bounced forward a few s t e p s . A few young rams l i t e r a l l y see-sawed be h i n d the ewe. Walther (1961) 1 0 4 d e s c r i b e d a s i m i l a r s e e - s a w c o u r t s h i p f o r a M a r c o P o l o r a m . E s t r u s i n e w e s T h e e n d o f N o v e m b e r b r i n g s a s l i g h t c h a n g e i n t h e b e h a v i o u r o f t h e l a r g e r r a m s . O n e o l d r a m b e g i n s t o g u a r d a e w e . H e h o r n - t h r e a t e n s s u b o r d i n a t e s o r b l o c k s t h e i r w a y t o t h e e w e b y i n t e r c e p t i n g t h e m i n a p r e s e n t . H e m a y k i c k t h e s u b o r d i n a t e a f e w t i m e s o r p u s h h i m a w a y w i t h h i s s h o u l d e r s o r c h e s t . S m a l l e r r a m s w i t h d r a w o r k e e p t h e i r d i s t a n c e a n d m o v e o n t o c o u r t u n g u a r d e d e w e s . N o t h i n g i n t h e f e m a l e ' s b e h a v i o u r i n d i c a t e s t h e a p p r o a c h o f e s t r o u s . S h e s t i l l w i t h d r a w s f r o m t h e k i c k s a n d p e r m i t s n o m o u n t i n g . O c c a s i o n a l l y t h e g u a r d i n g r a m m a k e s a s h o r t h o r n - r u s h a h e a d o f t h e e w e i f s h e b e g i n s t o w a l k a w a y , a n d i t i n v a r i a b l y m a k e s h e r t u r n . I n t h i s p r e - e s t r o u s p e r i o d t h e g u a r d i n g l a r g e r a m k e e p s c l o s e t o h e r , f e e d s , r e s t s , d i s c o u r a g e s o t h e r r a m s f r o m c o u r t i n g t h e e w e , a n d d i s p l a y s t o h e r p e r i o d i c a l l y . A g r o u p o f r a m s f o l l o w i n g o n e e w e i n d i c a t e s t h a t t h e e w e w i l l s h o r t l y e n t e r i n t o e s t r o u s o r i s a l r e a d y i n i t ( F i g . 9 0 ) . R i g h t b e h i n d t h e e w e i s t h e l a r g e s t h o r n e d , d o m i n a n t r a m w h o d i s c o u r a g e s o t h e r s f r o m p a s s i n g b y w h i r l i n g t o f a c e o r r u s h a t a n y s u b o r d i n a t e w h o a t t e m p t s i t . I f a s m a l l e r r a m d o e s s u c c e e d i n g e t t i n g p a s t t h e g u a r d i n g f u l l c u r l , h e g e t s b e h i n d t h e e w e a n d a w i l d c h a s e r e s u l t s . W h i l e t h e f e m a l e f l e e s , t h e s m a l l e r r a m a t t e m p t s t o m o u n t 105 h e r i n f u l l f l i g h t . The guarding male i s r i g h t at h i s h e e l s , b u t t i n g h i s rump and u s u a l l y succeeds i n knocking the s m a l l e r ram o f f the ewe. In most i n s t a n c e s the dominant l i t e r a l l y c rashes i n t o the f l a n k s of the mounting subordinate and sends him s p r a w l i n g ( F i g . 91). At t h i s p o i n t a s h o r t , sharp, v i c i o u s f i g h t between the guarding ram and a near equal may e r u p t . However, i t breaks up q u i c k l y f o r a s m a l l e r ram may be p u r s u i n g the ewe. V i c i o u s sideways b u t t i n g develops between the guarding ram and a subordinate i f i t attempts to pass. F o r a s h o r t s t r e t c h the two rams run shoulder to shoulder, b u t t i n g at each other u n t i l the dominant f o r c e s the subordinate i n t o another d i r e c t i o n and g i v e s him a p a r t i n g blow on haunches and f l a n k . U s u a l l y the dominant soon gets b e h i n d the ewe and the chase ends - i f the female i s i n e s t r o u s . Once the rams have been e x c i t e d by a chase, and the female does not stand, the dominant, f o l l o w e d by the s u b o r d i  nate^, pursues h e r . The ewe attempts to escape the rams by r u n n i n g i n t o steep c l i f f s or f o r e s t , p r e f e r a b l y both, and here b e g i n her e v a s i v e manoeuvres, (a) I f a ram i s r i g h t on her t a i l , she may jump up h i g h , t u r n by 180° and run past the rams. (b) She runs past a very narrow spot on the t r a i l , t u r n s , steps on to the narrow spot, presses her s i d e a g a i n s t the rock f a c e and f a c e s the rams. 106 (c) She jumps o f f the t r a i l on t o a narrow f o o t h o l d on a c l i f f f a c e where there i s only room enough f o r h e r . (d) She stops and presses her s i d e a g a i n s t a c l i f f f a c e and ho l d s s t i l l while rams f r u i t l e s s l y t r y t o mount h e r . (e) She comes to a crack i n the c l i f f s , q u i c k l y t u r n s and hacks i n t o i t . ( f ) She throws h e r s e l f on the ground and f o r a while r e s i s t s a l l attempts by the rams to get her up. (g) She z i g - z a g s while g a l l o p i n g over an open s l o p e . Every time a ram t r i e s t o mount, she dashes sideways. The most common k i n d of e v a s i v e a c t i o n s o f the ewe appear t o be a, b, c and d. None of these w i l l be f r e q u e n t l y observed f o r a number of reasons. When e s t r o u s ewes depart i n t o c l i f f s or timber, they u s u a l l y escape o b s e r v a t i o n . Some times, they run e n t i r e l y out of the study area o r c r o s s through i t d u r i n g p u r s u i t by rams. I f deep snow covers the ground, the chases tend t o be more l o c a l i s e d . T h i s impression I gained while comparing the Stone's r u t i n 1961, when deep snow covered the ground, w i t h the r u t i n 1962 and 1965 when almost no snow l a y on the mountains. None of the ewe's escape a c t i o n s appears t o be very s u c c e s s f u l . The e x c i t e d rams k i c k and push her, and aLmost wedge her away from rock f a c e s or out of c r e v i c e s t i l l she dashes o f f . Ewes which threw themselves down were k i c k e d 107 and b u t t e d to t h e i r f e e t . The chased ewes gave up r a t h e r quickly.. They began t o l e r a t i n g k i c k s and stood f o r mounting. Stone's rams h o l d i n g an e s t r o u s ewe d e l i v e r e d a s e r i e s o f k i c k s and then mounted, then d e l i v e r e d another s e r i e s of k i c k s , b e f o r e mounting a g a i n . The frequency w i t h which rams c o u r t and mount appears to depend on how much c o p u l a t i n g they have done p r e v i o u s l y . On December 7, 1961, I observed a 12 year o l d Stone's ram chase down and b e g i n b r e e d i n g the f i r s t e s t r o u s ewe of one band. In one hour he not o n l y chased down the ewe but mounted her 11 times. Then the r u t t i n g group disappeared from s i g h t . The f o l l o w i n g morning the 12 year o l d f u l l c u r l was markedly l e s s v igorous i n h i s defence of the female and he d i d not mount. A 4 year o l d c l a s s I I ram managed to s t e a l the ewe from the guarding ram and chase her i n t o some broken c l i f f s . The o l d ram searched f o r , but d i d not f i n d , the couple. In the f o l l o w i n g three hours the young ram mounted the ewe 39 times. Then the o l d ram r e t u r n e d and found b o t h . The young ram l e f t the ewe uncontested, but the o l d ram d i d not mount again and soon moved away l e a v i n g the ewe to s m a l l e r rams. A seven year o l d f u l l c u r l , mounted an e s t r o u s ewe on the second day of her heat o n l y 11 times, and o n l y a f t e r e x t e n s i v e c o u r t s h i p by the ewe. A f t e r the f i r s t excitement estrous ewes appear to be mounted on l y 2 - 3 times per hour. D e s p i t e the presence 108 of t he ewe, I have seen two guarding f u l l c u r l e d rams e j a c u l a t e spontaneously. Most of the time the e s t r o u s ewe feeds, while the l a r g e dominant ram stands between h e r and the sub o r d i n a t e s ( F i g . 9 2 ) . He r a r e l y f e e d s , but mainly stands w a t c h f u l l y b e s i d e the ewe and o c c a s i o n a l l y c o u r t s and mounts h e r . P e r i o d i c a l l y one of the s m a l l e r rams approaches the couple and l o o k s at them. The dominant may r e a c t i n s e v e r a l ways. He may l o w - s t r e t c h a t the subordinate, t w i s t , growl and advance a d i s t a n c e towards the i n t r u d e r . He may l i f t a f r o n t l e g and wave i t at the s u b o r d i n a t e . T h i s u s u a l l y s u f f i c e s and the subordinate r e l u c t a n t l y steps back while i n c l i n i n g the horns at the dominant and g l a n c i n g backward. Then he suddenly s p i n s around and dashes o f f , which o f t e n t r i g g e r s the dominant i n t o a short but hot p u r s u i t w i t h lowered head. A. dominant d i s c o v e r i n g a subordinate c l o s e by, may charge him at once with a lowered head ( F i g . 93)• Sometimes the dominant p u l l s up i n t o a present and slams h i s chest a g a i n s t the body of the s u b o r d i n a t e . At the same time he k i c k s and pushes the s m a l l e r ram d o w n h i l l . Or, the dominant may b l o c k the way to the ewe by assuming a present and t u r n i n g broadside t o the i n t r u d e r ( t h i s may g i v e the f a l s e i m p r e s s i o n t h a t rams have a bro a d s i d e d i s p l a y ) . U s u a l l y the guarding ram i s a l a r g e f u l l c u r l and h i s l a r g e s t competitor i s u s u a l l y a 6 - 7 year o l d c l a s s I I I ram. Such rams need not be h e s i t a n t i n t h e i r approach t o the 109 b r e e d i n g p a i r . They can a t t a c k and f o r c e f u l l y b u t t o r c l a s h while t r y i n g t o break through t o the estrous ewe. T h i s can l e a d to short v i c i o u s f i g h t s i n which the c l a s s I I I ram may suddenly d i s c o v e r h i m s e l f c l o s e t o the ewe and a t once g i v e chase. He w i l l succeed now and again i n d r i v i n g o f f the ewe, p a r t i c u l a r l y i f the dominant ram i s exhausted, and w i l l b e g i n t o cop u l a t e and defend h e r a g a i n s t s m a l l e r rams, j u s t as the l a r g e r ram d i d p r e v i o u s l y . I f the f u l l c u r l s are bad runners due to exhaustion, or perhaps lungworm i n f e c t i o n , these 6 - 7 year o l d rams may do an abnormally l a r g e p a r t o f the b r e e d i n g . T h i s s i t u a t i o n was present i n 1964 on the b i g h o r n study area i n Banff Park. When the guarding ram i s l a r g e and s u c c e s s f u l l y i n t e r c e p t s the approaches o f subordinates so t h a t few chases r e s u l t , then most mounting i s done by the l a r g e ram. I f , however, the ram guards b a d l y due t o small s i z e or exhaustion so that many chases develop, then the subordinates do a con s i d e r a b l e amount of mounting. F o r i n s t a n c e : November 19, 1964, I observed f o r 88 minutes a group of b i g h o r n rams about a b r e e d i n g p a i r . The guarding ram was very l a r g e ( F i g . 92) and o n l y a few sh o r t chases developed. The t h r e e c l a s s IV rams mounted a l t o g e t h e r 25 times, the I I I ram 3 times, the I I ram 7 times, and the two I rams 4 times, and a y e a r l i n g male none a t a l l . T h e r e f o r e , 25 of 39 mounts attempted were 110 made by the f u l l c u r l s of which almost a l l were hy the guarding ram. On November 30, 1964, I observed f o r 25 minutes a r u t group i n which a l o t of c h a s i n g took p l a c e . The two IV rams mounted 13 times, the I I I ram 14 times, the t h r e e I I rams mounted 15 times, and the I ram mounted t w i c e . In t h i s s i t u a t i o n , where a v i g o r o u s I I I ram s u c c e s s f u l l y chased o f f the ewe from an o l d guarding f u l l c u r l , the f u l l c u r l s performed only 13 o f 45 mounts. Among the Stone's sheep I observed, small rams had l i t t l e chance t o mount estrous ewes due to the v i g o r o u s , s p i r i t e d defence by l a r g e , even ve r y o l d rams. The bighorns I observed appeared l i s t l e s s and very t i r e d by comparison and were n o t i c e a b l y s h o r t of b r e a t h / T h i s may w e l l be the reason why s m a l l e r rams mounted estrous ewes r a t h e r o f t e n on the Banff study a r e a . Mounting f r e q u e n c i e s by v a r i o u s c l a s s e s of rams on e s t r o u s ewes are g i v e n i n G e i s t (1966c. F i g . 14). A ram defends the e s t r o u s ewe a g a i n s t s m a l l e r rams. P e c u l i a r l y enough though, when a l a r g e r ram a r r i v e s on the scene, the s m a l l e r one l e a v e s the ewe without a c o n t e s t . They walk h e s i t a n t l y away from the dominant who then begins t o c o u r t the ewe. They do not a t t a c k , nor are they capable a p p a r e n t l y of comprehending t h a t they c o u l d have e a s i l y chased the ewe away t o another l o c a l i t y . I t appears t h a t when a ram runs a f t e r a ewe he i s not chasing, but r a t h e r f o l l o w i n g , an e s c a p i n g female. Herding the ewe out of the way when a I l l l a r g e r r i v a l a r r i v e s , i s not p a r t of h i s normal be h a v i o u r . Twice I saw guarding f u l l c u r l rams l e a v e the ewe v o l u n t a r i l y , f e e d , r e s t and pay no a t t e n t i o n t o the next l a r g e s t ram who took over the ewe, c o p u l a t e d , and defended h e r a g a i n s t s m a l l e r c o m p e t i t o r s . In both i n s t a n c e s the l a r g e r rams r e t u r n e d a f t e r r e s t i n g , walked over to the e s t r o u s ewe, and the s m a l l e r guarding ram l e f t . Only once d i d I see two ewes i n e s t r o u s i n the same band. They were p e r i o d i c a l l y exchanged between the two l a r g e s t rams. When one l e f t h i s ewe and walked over to the other b r e e d i n g couple, the s m a l l e r ram l e f t and went over to the ewe h i s l a r g e r opponent d e s e r t e d . On two occasions a r a t h e r unusual i n t e r a c t i o n was observed. In b o t h i n s t a n c e s a c l a s s I I I Stone's ram moved suddenly i n present a g a i n s t the s l i g h t l y l a r g e r guarding ram, slammed h i s chest a g a i n s t the l a t t e r 1 s s i d e and proceeded t o k i c k and d i s p l a y . These two subordinates then a c t e d as i f they were dominants. In b o t h i n s t a n c e s the dominant's r e s  ponse was t o w h i r l around and c l a s h i n t o t h a t s u b o r d i n a t e . Once, while the dominant turned, the subordinate q u i c k l y mounted him. In both i n s t a n c e s the subordinate rams q u i c k l y dashed away, f o l l o w e d c l o s e l y by the c h a r g i n g dominant over a s h o r t d i s t a n c e . Ewes i n e s t r o u s r e t u r n e d on t h e i r own t o the l a r g e s t ram and o c c a s i o n a l l y c o u r t e d him as w i l l be d e s c r i b e d l a t e r . 112 The group o f subordinate rams which gathers about a b r e e d i n g couple, i s f a r from p a s s i v e . They i n t e r a c t e x t e n s i v e l y w i t h each o t h e r . L a r g e r rams co u r t and mount s m a l l e r ones as i f these were es t r o u s ewes whose behaviour they resemble ( P i g . 7 5 ) . L a r g e r rams may n u z z l e the penis of the s m a l l e r and l i p c u r l . G e n e r a l l y the s m a l l e r ram stands, except when b e i n g mounted e x c e s s i v e l y . Twice I saw a small Stone's ram b e i n g chased by a c o u r t i n g I I I ram. The chases went over c l i f f regions;!and the l a r g e r attempting to mount on the s m a l l e r . The I I I rams p u r s u i n g and r a p i n g a s m a l l e r ram i g n o r e d non-estrous ewes they passed. Once d u r i n g a chase a c l a s s I I I Stone's ram mounted the l a r g e defending f u l l c u r l i n f r o n t o f him. The f u l l c u r l w h i r l e d and h e a v i l y c l a s h e d i n t o the o f f e n d e r ' s body. In the i n t e r a c t i o n s between rams about e s t r o u s ewes, the guarding ram tended t o deal out more blows and r e c e i v e l e s s than the o t h e r rams. Thus i n i n t e r a c t i o n s about 9 e s t r o u s ewes on which I r e c o r d e d q u a n t i t a t i v e l y , 10 c l a s s IV rams d e a l t out 36 blows and r e c e i v e d 9, 12 I I I rams d e a l t out 17 and r e c e i v e d 36, and 7 I I rams d e a l t out 2 and r e c e i v e d 9. Though c l a s s I rams do d e a l out some blows and r e c e i v e d some i n r e t u r n , they i n t e r a c t e d too l i t t l e t o be r e c o r d e d . As s t a t e d e a r l i e r , f i g h t s about the e s t r o u s ewe tend to be un- r i t u a l i s e d , and v i c i o u s . However, once I d i d see two rams 113 f i g h t i n r i t u a l i s e d f a s h i o n f o r a few minutes b e f o r e dashing o f f a f t e r the ewe. U n l i k e the su b o r d i n a t e s , the guarding l a r g e ram feeds and r e s t s l i t t l e . The ewe u s u a l l y f e e d s . When no e s t r o u s ewe i s pr e s e n t , the l a r g e ram a g a i n feeds r e g u l a r l y and does not i n t e r f e r e w i t h the c o u r t s h i p s of subordinate rams on non-estrous females. I observed, however, a number of times t h a t e x c e s s i v e i n t e r e s t o f one ram toward a ewe q u i c k l y e x c i t e d o t h e r s . At once the l a r g e s t began to defend h e r and attempt c o p u l a t i o n even though she was not i n e s t r o u s . Then, as soon as he was alone w i t h the ewe he showed no more i n t e r e s t and l e f t h e r . The ewe was i n t e r e s t i n g only when pursued by o t h e r rams. On the Stone's sheep study area ewes came i n t o heat r a t h e r l a t e i n the ye a r . I observed the f i r s t ewe i n es t r o u s on November 25, and the l a s t on December 16. In t o t a l I saw 16 Stone's ewes i n heat i n the complete r u t t i n g seasons of 1961 and 1962, p l u s the g r e a t e r p a r t of the 1965 r u t (November 27 - December 10). One i n d i v i d u a l l y known ewe was i n e s t r o u s i n 1961 on December 4, i n 1962 on December 2, and i n 1965 on November 29. On the b i g h o r n study area i n Banf f , i n 1964, I observed the f i r s t ewe i n e s t r o u s on November 19, and the l a s t on December 4; I saw f i v e e s t r o u s b i g h o r n ewes. One a d u l t Stone's ewe remained of i n t e r e s t t o rams on t h r e e c o n s e c u t i v e days, while a 2^ year o l d ewe of the same p o p u l a t i o n 114 remained of i n t e r e s t f o r o n l y two days. S i n c e the ewes have d e f i n i t e w i n t e r i n g areas, they tend t o he bred on s u c c e s s i v e years i n the same general l o c a l i t y . N-ewe, mentioned above, was b r e d i n 1961, 1962 and 1965 i n the same c l i f f s . She was guarded and b r e d i n 1962 and 1965 by the same ram. S e v e r a l p o i n t s are important. Mountain sheep h e r d no harems but defend each e s t r o u s ewe as she reaches e s t r u s . Non-estrous females, which mountain goat, e l k or moose, guard, may be c o u r t e d w i t h impunity by s m a l l e r males i n the presence of a l a r g e r . U n l i k e the c e r v i d s or the mountain goat, rams f e e d d u r i n g the r u t except f o r the guarding ram about an e s t r o u s female when p o t e n t i a l c h a l l e n g e r s are p r e s e n t . U n l i k e some A f r i c a n antelope, i . e . Adenota (Buechner, 1961) or G a z e l l a thompsoni (Walther, 1964), which c o u r t and breed f e  males on a mating t e r r i t o r y u nchallenged by other males, mountain sheep experience i n t e n s e c h a l l e n g e about the e s t r o u s ewe. The b r e e d i n g success of rams i n h e a l t h y p o p u l a t i o n s d e c l i n e s s h a r p l y w i t h t h e i r dominance rank. Probably a l l e s t r o u s females are inseminated by s e v e r a l rams although v i r t u a l l y a l l the f i r s t 20 - 50 c o p u l a t i o n s are performed by the l a r g e s t ram. In the presence of the ewe, the s u b o r d i n a t e s mount s m a l l e r companions e x t e n s i v e l y ; i t i s i n t h i s s i t u a t i o n t h a t the ram's tendency to t r e a t subordinates a l i k e ( i r r e s  p e c t i v e of sex) m a n i f e s t s i t s e l f c l e a r l y . There are be h a v i o u r a l d i f f e r e n c e s between p o p u l a t i o n s . Thus, the o l d , 115 l a r g e b i g h o r n rams I observed i n B a n f f appeared t o s u f f e r from a shortage of b r e a t h which may have been caused by lungworm i n f e c t i o n . P a n t i n g h e a v i l y they attempted to f o l l o w the d e p a r t i n g younger rams w i t h the e s t r o u s ewe. Then they gave up and began to f e e d . They had no d i f f i c u l t y r e c l a i m i n g the ewe once the chase came t o an end, by simply walking over. The s m a l l e r guarding ram l e f t . I t was apparent, d e s p i t e i n s u f f i c i e n t q u a n t i t a t i v e data, t h a t here the younger rams assumed a l a r g e r p a r t o f the b r e e d i n g . The a c t i o n s of a l l the rams about the e s t r o u s ewe were much more l e t h a r g i c than those o f Stone's rams and the s p i r i t e d i n t e r  a c t i o n s between rams were few. However, the bighorns d i d not appear t e r r i b l y exhausted a f t e r the r u t as were some l a r g e , o l d Stone's rams. C o u r t s h i p by the ewe T h i s behaviour i s very r a r e l y seen. From 21 es t r o u s females which I observed, o n l y t h r e e d i d some c o u r t i n g . I t appears t h a t female c o u r t s h i p a r i s e s o n l y under r a r e circum s t a n c e s : The ewe i s c o u r t e d by one s i n g l e male and the ram i s a l r e a d y exhausted from frequent c o p u l a t i o n s . In the presence of s e v e r a l rams, the exhausted dominant would be q u i c k l y r e l i e v e d by eager subordinates as I d e s c r i b e d e a r l i e r . There would then be no need f o r the ewe to s t i m u l a t e an exhausted ram. 116 I observed the ext e n s i v e c o u r t s h i p s of a Stone's ewe on December 4, 1961, under above circumstances. A seven year o l d f u l l c u r l had a s s o c i a t e d h i m s e l f i n l a t e November with a 12 year o l d ewe and h e r two f o l l o w e r s , a y e a r l i n g female and a ram-lamb. On the morning of December 4 the o l d ewe was w e l l i n heat and the ram a l r e a d y exhausted. D u r i n g the day I witnessed 26 i n t e r a c t i o n s between the breed i n g couple, of which 18 were i n i t i a t e d by the ewe. The ram i n i t i a t e d o n l y e i g h t i n t e r a c t i o n s on the o l d ewe, f i v e on the lamb and th r e e on the y e a r l i n g female. The behaviour o f the c o u r t i n g ewe i s best d e s c r i b e d from a sample of my notes: "N-ewe has been f e e d i n g a l i t t l e . Now she stands f a c i n g away from F-ram. Suddenly she b o l t s , and F-ram almost r e f l e x - l i k e bounds a f t e r h e r a few paces and f r e e z e s i n a l o w - s t r e t c h . N-ewe w h i r l s and h o r n - t h r e a t e n s F ( F i g . 94). Then she comes and rubs h e r s i d e a l o n g h i s body while he stands f r o z e n i n a l o w - s t r e t c h . Again she bounds away a few paces, t u r n s , b u t t s F-ram on the head, jumps back agai n , horn-threatens then ducks under h i s c h i n and rubs her s i d e and haunches a l o n g h i s chest F i g . 94) and neck, and stops with her haunches p r e s s e d a g a i n s t h i s c h e s t . F-ram assumes a p o s i t i o n d i r e c t l y b e hind h e r and mounts t h r e e times i n r a p i d s u c c e s s i o n . 117 N-ewe moves forward a l i t t l e and F-ram f o l l o w s . She moves again, but he remains s t a n d i n g , N-ewe t u r n s h e r head and look s at the ram who has begun to g r a z e . N-ewe turns and moves back to F-ram, She goes c l o s e t o him and feeds p a r a l l e l with the ram almost i n body c o n t a c t . T h i s l a s t s a few minutes. Then N-ewe h o r n - t h r e a t s t o F-ram, s l i p s under h i s neck and rubs h e r s i d e again a l o n g h i s c h e s t . She stops f o r a moment wit h h e r haunches a g a i n s t h i s chest and then steps forward. F-ram makes a sudden r u s h at her wit h lowered head. She avoi d s him, t u r n s and b u t t s him on the head. Then she moves c l o s e b e s i d e him and both walk i n l o w - s t r e t c h - a p p a r e n t l y i n body co n t a c t - s e v e r a l paces forward. Both stop s i m u l t a n e o u s l y . She t u r n s and t r o t s away, but stopsaand l o o k s at F-ram. F-ram j u s t s t a n d s . Then he paws a bed and l i e s down. N-ewe does l i k e w i s e . " The behaviour p a t t e r n s o f the c o u r t i n g ewe i n c l u d e hence, a sudden bounding away, which I termed a "coquette run" ( F i g . 94A) . T h i s run i s short and i s te r m i n a t e d by the ewe t u r n i n g towards the ram. Durin g h e r approach i n h o r n - t h r e a t the ewe may prance a l i t t l e ( F i g . 94B). She o f t e n horns and b u t t s the chest and shoulders o f the ram ( F i g . 94C) b e f o r e r u b b i n g her body al o n g h i s chest ( F i g . 94D). N-ewe n u z z l e d the 118 head of F-ram o n l y twice i n 26 i n t e r a c t i o n s , however, t h i s b ehaviour was shown more f r e q u e n t l y by a 2^ year o l d ewe i n h e r f i r s t heat p e r i o d . In the 26 i n t e r a c t i o n s , N-ewe performed the h o r n - t h r e a t approach 17 times, horned the ram's body 10 times, performed the coquette run 10 times and b u t t e d F-ram t h r e e times. F-ram mounted h e r 11 t i m e s . In one r e s p e c t the ram behaved u n u s u a l l y . He charged the ewe q u i t e o f t e n , seven times i n t o t a l , and a l s o charged the y e a r l i n g female t w i c e . Both ewes evaded him e a s i l y . The behaviour of the c o u r t i n g , e s t r o u s ewe i s s i m i l a r t o t h a t of the young ram towards an o l d e r ram. L i k e the l a t t e r , she accepts f r o n t - k i c k s and t w i s t s without running away; she approaches the dominant i n h o r n - t h r e a t on her own; she b u t t s , horns and n u z z l e s him; she arches her back when mounted. She d i f f e r s o n l y i n t h a t she performs coquette runs and seeks body co n t a c t h e r s e l f . The l a t t e r i s a c h i e v e d i n the normal i n t e r a c t i o n s of rams by the dominant pushing h i s chest a t the subordinate's s i d e . The e s t r o u s ewe, hence, shows(a remarkable behaviour r e v e r s a l . P o s t - r u t A f t e r the r u t t i n g season, most rams r e t u r n from the ewe ranges t o t h e i r own s p e c i f i c w i n t e r i n g a r e a s . On the Stone's sheep study area, which was t h i n l y p o p ulated w i t h sheep, rams were much more s o l i t a r y a f t e r the r u t than a t 119 oth e r seasons. T h i s i s shown i n F i g . 95. In January, 1962, when deep snow f o r c e d rams on to a l i m i t e d w i n t e r i n g a r e a , the s o l i t a r y tendency was much l e s s apparent than i n January, 1963, when very l i t t l e snow l a y on the ground and the rams d i s p e r s e d . In 1962, as the winter moved on i n t o s p r i n g , rams became i n c r e a s i n g l y more s o c i a l and formed bands. Older rams were more s o l i t a r y than the younger ones ( F i g . 9 6 ) . I t can be noted t h a t o n l y a f t e r 7 - 9 years o f age was the tendency to go about alone v e r y conspicuous. 120 PART IV ON THE EVOLUTION OP MOUNTAIN SHEEP I n t r o d u c t i o n The C a p r i n i are a s u c c e s s f u l t r i b e o f ruminants. They have spread to v i r t u a l l y a l l major mountain ranges i n the n o r t h e r n hemisphere, and ev o l v e d great d i v e r s i t y i n e x t e r n a l appearance, s i z e and c l i m a t i c a d a p t a t i o n s . D e s p i t e t h i s d i v e r s i t y , they appear to be very c l o s e l y r e l a t e d as i s i n d i c a t e d by h y b r i d i s a  t i o n experiments. A l l w i l d sheep t h a t have been cros s e d with domestic sheep have produced v i a b l e , f e r t i l e h y b r i d s , as do i n t e r s p e c i f i c c r o s s e s i n the genus Capra (Krumbiegel 1954, P e t z s c h 1957, Young and M a n s v i l l e I 9 6 0 ) . Hybrids have been obtained from the i n t e r g e n e r i c c r o s s e s of Ammotragus and Capra ( P l e t z s c h 1957 a) and Hemitragus and Capra (see Krumbiegel 1954)• One can o b t a i n h y b r i d s even from such d i s t a n t genera as Ovis and Capra. but onl y a f t e r some l a b o r a t o r y m a n i p u l a t i o n of the semen and a r t i f i c i a l i n s e m i n a t i o n (see Schmitt 1 9 6 3 ) . On the whole, the genomes of r a t h e r d i v e r s e c a p r i d s are sur p r i s i n g l y compatible. F o s s i l evidence i n d i c a t e s t h a t the c a p r i d s are evolu- t i o n a r i l y very young. Ovis and Capra appear f o r the f i r s t time i n the e a r l y P l e i s t o c e n e . They are preceded by S i v i c a p r a and the l a t e P l i o c e n e genus To s s u n n o r i a from China (Thenius and Hofer 1 9 6 0 ) . The great d i v e r s i t y of forms found i n the C a p r i n i ap p a r e n t l y evolved i n the short time-span of the P l e i s t o c e n e . The c a p r i d s are t h e r e f o r e d i v e r s e , c l o s e l y r e l a t e d and appear to be young. T h i s i n d i c a t e s t h a t they a p p a r e n t l y evolved very r a p i d l y . The purpose of t h i s chapter i s to examine how 121 they evolved m o r p h o l o g i c a l l y and b e h a v i o u r a l l y , and to e x p l a i n the s e l e c t i o n f o r c e s r e s p o n s i b l e f o r the d i r e c t i o n and speed o f t h e i r e v o l u t i o n . The P r i m i t i v e C a p r i d s . The f o s s i l evidence i n d i c a t e s t h a t c a p r i d s evolved from r u p i c a p r i d a n c e s t o r s (Thenius and Hofer 1960) . I f t h i s i s t r u e , then the most p r i m i t i v e c a p r i d i s the one which most c l o s e l y resembles the r u p i c a p r i d s . T h i s would be Hemitragus. I t i s s u r p r i s i n g how many f e a t u r e s i t has i n common with the American goat-antelope (Oreamnos). T y p i c a l r u p i c a p r i d c h a r a c t e r i s t i c s of Hemitragus are the h a i r - p a n t s on f r o n t and h i n d l e g s , the w e l l developed h a i r r i d g e , the l a c k of a rump patch, the narrow, p o i n t e d e a r s , the r a t h e r s h o r t , backward p o i n t i n g and annulated horns, the s m a l l sexual dimorphism i n h o r n s i z e and shape, as w e l l as the f o u r t e a t s , of which however o n l y the l a s t p a i r are u s u a l l y f u n c t i o n a l (Rammel and Caughley 1964). L i k e Oreamnos. Hemitragus males p a i r o f f d u r i n g the r u t with one female and a p p a r e n t l y guard h e r i n the non-estrous s t a t e , yet f i g h t so r a r e l y t h a t f i g h t s have not yet been witnessed (Anderson and Henderson 1961) . Oreamnos males f i g h t p r i m a r i l y by the hooking of t h e i r opponents r e a r and b e l l y and c a r r y as a primary p r o t e c t i o n a t h i c k h i d e (p. 5 5 ) . We do not know how Hemitragus f i g h t , however, they have k i l l e d deer i n Woburn park by disembowelling them (Anderson and Henderson 1961). They c o u l d only achieve t h a t by hooking at the b e l l y of t h e i r v i c t i m i n the manner of Oreamnos. Furthermore, Hemitragus males have a t h i c k , heavy h i d e . I t may weigh as much as 60 pounds from males i n w i n t e r c o a t which 122 weigh 300 - 350 l b s . The h i d e from a nine year o l d Oreamnos male shot i n e a r l y w i n t e r weighed 35 l b s ; the males l i v e weight was c a l c u l a t e d at 246 l b s . I t i s l i k e l y t h a t the t h i c k h i d e i n males o f both genera evolved as p r o t e c t i o n a g a i n s t a s i m i l a r mode of combat. Males of both genera engage opponents w i t h a b r o a d s i d e t h r e a t d i s p l a y . However. Hemitragus uses a s t r e t c h e d p osture and does not p u l l the head from the opponent as does Oreamnos. Hemitragus i s hence s i m i l a r t o r u p i c a p r i d s except f o r the broad, s h a r p l y k e e l e d h o rns. The k e e l , I suggest, i s an a d a p t a t i o n which i n c r e a s e s the e f f e c t i v e n e s s of b u t t i n g by l o c a l i z i n g the f o r c e over a s m a l l e r s u r f a c e area than would round h o r n s . I t i s probable t h a t Hemitragus males w i l l attempt to c a t c h some blows of t h e i r opponents w i t h the horns. I t i s a l s o l i k e l y t h a t — a s i n Oreamnos—there w i l l be o n l y one f i g h t i n g type i n Hemitragus. and i t w i l l be comparable t o the v i c i o u s , u n r i t u a l i s e d brawls of Ovis males (p. 98 ) . A d i s t i n c t i o n between v i c i o u s and r i t u a l i s e d f i g h t s w i l l probably not be p o s s i b l e . The r u p i c a p r i d a n c e s t r y i s s t i l l apparent i n Ammotragus. the next most p r i m i t i v e c a p r i d , but i t a l s o has f e a t u r e s , r e m i n i  scent o f sheep* Ammotragus i s p r i m i t i v e i n t h a t i t s t i l l uses a horn t h r u s t l i k e Oreamnos (Katz 1949); i t i s the on l y c a p r i d b e s i d e Hemitragus which can i n f l i c t stabwounds with i t s horns (Haas 1958). On t h i s b a s i s i t seems probable t h a t o l d Ammotragus rams w i l l have a t h i c k h i d e . Sexual dimorphism i s r e l a t i v e l y s m a l l , w h i l e females are a g g r e s s i v e and can keep males at a 123 d i s t a n c e (Ogren 1965, Haas 1958). These are both r u p i c a p r i d f e a t u r e s . Ammotragus has no rump patch, i t s t a i l i s l o n g , i t s ears are t y p i c a l l y r u p i c a p r i d and i t s males ap p a r e n t l y l i v e s o l i t a r i l y except d u r i n g the r u t (see Brehm 1916). Ammotragus i s advanced i n t h a t males i n t e r a c t f r e  q u e n t l y and not only b u t t , but a l s o c l a s h . The c l a s h e s are l e s s f o r c e f u l than those of sheep, but seem to be otherwise s i m i l a r t o those of mouflon (0. musimon). Ammotragus males a l s o w r e s t l e by hooking horns and neck f i g h t , behaviour p a t t e r n s which are present i n rudimentary form i n American sheep (p. 4 4 ) , These behaviour p a t t e r n s may be somewhat s p e c i a l i z e d d e r i v a t i v e s o f the v i c i o u s , g e n e r a l i z e d f i g h t . As yet we do not know how two l a r g e r i v a l males f i g h t . I t i s u n l i k e l y t h a t t h e i r combat forms w i l l be as r i t u a l i z e d as those of advanced sheep (p. 90). Ammotragus rams w i l l most l i k e l y show a mixture of some r i t u a l i z e d c l a s h i n g and v i c i o u s w r e s t l i n g , neck f i g h t i n g and o c c a s i o n a l hooking at the opponents f l a n k or r e a r . As i n sheep, the estrous female i s guarded by one male a g a i n s t s e v e r a l o t hers (Ogren 1965). Subordinate Ammotragus males 5unable to reach the female i n heat, may mount each other aS do sheep but no known r u p i c a p r i d . L i k e Capra or Ovis. Ammotragus males commonly e j a c u l a t e spontaneously, but resemble goats by t a k i n g the penis i n t o t h e i r mouths (Haas 1958). Ammotragus rams are not malodorous, they have o n l y a short h a i r r i d g e run n i n g d o r s a l l y along the neck t o the w i t h e r s — j u s t l i k e a l l u r i a l s and a r g a l i s , they c a r r y a cheek beard and a v e n t r a l t h r o a t mane which i s s i m i l a r , but more e x t e n s i v e than t h a t o f u r i a l s , and they possess r e l a t i v e l y l a r g e horns w i t h heteronym winding 124 Although Ammotragus may c r o s s w i t h Capra (P e t z s c h 1957 b ), i t has a bloo d serum p r o t e i n p i c t u r e s i m i l a r t o t h a t of Ovis but not Capra (Schmitt 1963). A p r e s e n t - t h r e a t has not yet been d e s c r i b e d f o r Ammotragus. I t may w e l l be an inconspicuous f r o n t o - l a t e r a l d i s p l a y , shown by a n t a g o n i s t i c l a r g e males p r i o r t o a s e r i o u s f i g h t . The * l o w - s t r e t c h appears t o be absent; the t w i s t appears t o be present i n c o u r t s h i p (Haas 1958), but a l s o as a t h r e a t (Katz 1949). I t i s however f a i r l y c e r t a i n t h a t n e i t h e r d i s p l a y nor contact behaviour are n e a r l y as w e l l developed and f r e q u e n t l y used as i n sheep. I s h a l l use Ammotragus as a b a s i s o f comparison w i t h advanced c a p r i d s . Changes i n the e x t e r n a l appearance of c a p r i d s L e t us t u r n now t o the e x t e r n a l appearance of c a p r i d s and see how i t changed. T h i s happens t o be b e t t e r known than other f e a t u r e s of c a p r i d b i o l o g y . But more important, the s t r u c t u r e and f u n c t i o n of c a p r i d a d a p t a t i o n s i s i n t e r r e l a t e d . P e t z s c h (1957 b ) p o i n t e d out t h a t Ammotragus. s t r i p p e d of i t s v e n t r a l mane3 i s s t r i k i n g l y s i m i l a r t o the Caucasian t u r (Capra c y l i n d r i c o r n i s ) . T h i s form blends i n t o the West Caucasian t u r (Capra c a u c a s i c a ) which s t r o n g l y resembles the t r u e ibex (Capra i b e x ) . I f these s p e c i e s are arranged i n order o f resemblance, we get the s e r i e s shown i n F i g . 97. * These forms of postures are d e s c r i b e d on p. 38 125 Ammotragus. however, resembles even more the western u r i a l s (Ovis ammon). p a r t i c u l a r l y the races ophion (Cyprus) and g e m e l i n i (Armenia)• We can assemble A s i a t i c sheep i n o r d e r of resemblance, put Ammotragus out f r o n t and o b t a i n the f o l l o w i n g l i n e up: Ammotragus. Ovis.ammon g e m e l i n i . o r i e n t a l i s . c y c l o c e r o s (the " a r k a l " form from T u r k e s t a n ) , s e v e r t z o v i . n i g r i m o n t a . p o l i . k a r e l i n i . ammon and d a r w i n i . T h i s s e r i e s i s p a r t i a l l y i l l u s t r a t e d i n F i g . 98. Other forms, such as ophion. musimon, or hodgsoni may be regarded as branches d e v i a t i n g from the proposed l i n e up. ( A l l d e s c r i p t i o n s based on C l a r k 1964, Geptner et a l , 1961, Lydekker 1898, 1913). On the b a s i s of e x t e r n a l appearance alone, Ammotragus can be regarded e q u a l l y w e l l as a p r i m i t i v e goat or as a p r i m i  t i v e sheep; i t a l s o l i n k s the most h i g h l y e v o l v e d goats and sheep i n t o one s e r i e s . The above mentioned s e r i e s of A s i a t i c sheep and Ammotragus. i s a l s o a geographic s e r i e s . Those forms which resemble each ot h e r most, are a l s o neighbours; the g r e a t e r t h e i r d i v e r s i t y , the f u r t h e r they are s i t u a t e d from each o t h e r ( F i g . 99). The s e r i e s s t r e t c h e s i t s e l f from North A f r i c a i n a s l i g h t l y curved l i n e t o Mongolia. The sheep s e r i e s runs furthermore from the o l d P l e i s t o c e n e r e f u g i a of North A f r i c a and southern A s i a , deep i n t o the f o r m e r l y g l a c i a t e d p a r t s of c e n t r a l A s i a . The advanced forms, c y c l o c e r o s t o d a r w i n i . c o u l d h a r d l y have been present where they are now d u r i n g the g l a c i a t i o n s . These appear to be forms which c o l o n i s e d 126 the v a s t expanse of l i v i n g space a f t e r the r e t r e a t of g l a c i e r s . The s e r i e s appears t o he a r e a l e v o l u t i o n a r y s e r i e s i n which one form gave r i s e t o the next more advanced one. T h i s i s a more reasonable e x p l a n a t i o n ; than the assumption t h a t each form e v o l v e d q u i t e independently b u t — b y some unexplained f e a t o f n a t u r e — l i n e d themselves up g e o g r a p h i c a l l y i n order of resemblance. L e t us see how these sheep changed e x t e r n a l l y . (1) The horns changed from a heteronym t o a homonym winding ( F i g . 9 8 ) , F i r s t they i n c r e a s e d i n l e n g t h and l a t e r i n mass ( i . e . p o l i horns p l u s upper s k u l l from an o l d ram weighs 25 l b s . , but i n ammon 49 l b s . ( C l a r k , 1964). The horns became s h a r p l y k e e l e d l a t e r a l l y . T h i s angle became reduced and almost l o s t i n k a r e l i n i to d a r w i n i ( F i g . 9 8 ). (2) The h a i r c o a t showed the f o l l o w i n g changes. The cheek-beard and v e n t r a l n e c k - r u f f were g r a d u a l l y reduced and then l o s t . The d o r s a l h a i r r i d g e was l o s t except f o r a s h o r t r i d g e on the neck. A, rump patch appeared and p r o g r e s s i v e l y i n c r e a s e d i n s i z e . The amount of white h a i r s i n c r e a s e d on the r e a r aspects o f h i n d and f r o n t l e g s . (3) The ears became s h o r t e r and rounder ( F i g . 98). (4) The sexual dimorphism i n c r e a s e d by the female becoming r e l a t i v e l y s m a l l e r i n body and h o r n s i z e and by her l o s i n g the neck r u f f ( F i g . 100). These m o r p h o l o g i c a l changes went on s i m u l t a n e o u s l y . Sheep w i t h the l a r g e s t horns a l s o tend to have the l a r g e s t rump patches, g r e a t e s t sexual dimorphism, and the l e a s t d i s p l a y h a i r . 127 On the b a s i s of these o b s e r v a t i o n s about the d i s t r i b u t i o n and d i f f e r e n c e s i n e x t e r n a l appearance of A s i a t i c sheep,one can formulate a t e n t a t i v e c o n c l u s i o n . I t appears, t h a t sheep e v o l u t i o n i s l i n k e d with t h e i r advance i n t o f o r m e r l y g l a c i a t e d t e r r a i n . Whenever they invaded new h a b i t a t which f o l l o w e d i n the wake of g l a c i a t i o n , they changed si m u l t a n e o u s l y i n s e v e r a l e x t e r n a l f e a t u r e s . I f these are v a l i d r e l a t i o n s h i p s , then they should apply to other sheep a l s o . With t h i s i n mind, l e t us t u r n to the next l a r g e group of sheep, the American sheep. These are a l l r a t h e r advanced sheep, compared to the A s i a t i c forms. They have l o s t the neck r u f f e n t i r e l y as w e l l as the d o r s a l r i d g e of h a i r on the neck. T h e i r horns are q u i t e l o n g and a l r e a d y massive. In eastern S i b e r i a , we f i n d the n i v i c o l a group. A l a s k a , the Yukon and no r t h e r n B r i t i s h Columbia are home of the dal 1 i group, while the canadensis races occupy;- western North America south of the Peace R i v e r to the t i p of Lower C a l i f o r n i a . I t i s g e n e r a l l y assumed t h a t sheep c r o s s e d to North America v i a the Bering-Chukchi p l a t f o r m from S i b e r i a and then spread a l o n g the mountain ranges of western North America down as f a r as Mexico. The Wisconsin g l a c i a t i o n separated sheep i n t o two major groups. Ovis d a l l i s u r v i v e d i n the Alaska-Yukon refugium and canadensis i n the southern refugium (Cowan 1940). I f the c o n c l u s i o n reached from A s i a t i c sheep i s v a l i d , then n i v i c o l a should be the most p r i m i t i v e of the American sheep, and c a n a d e n s i s — w h i c h moved f u r t h e s t — t h e most advanced form. 128 Sheep of the d a l l i group should be i n t e r m e d i a t e . There i s , however, a f u r t h e r c o n s i d e r a t i o n . A f t e r the Wisconsin g l a c i a t i o n , sheep invaded the f o r m e r l y g l a c i a t e d a reas. Hence, the most advanced forms should r e a l l y be found t h e r e , and not i n the o l d r e f u g i a . T h e r e f o r e , one should f i r s t compare sheep from the o l d r e f u g i a , and then sheep from the o l d r e f u g i a w i t h forms from the g l a c i a t e d areas. Indeed, n i v i c o l a does seem to be the most p r i m i t i v e . However, r e l a t i v e l y l i t t l e i n f o r m a t i o n e x i s t s about i t . In s i z e , i t i s s i m i l a r t o d a l l i and s t o n e i . C h e r n i a v s k i (1962) l i s t s l i v e weights of 154 - 167 l b s . (70-76 kg.) f o r rams 6 years of age or o l d e r . Geptner et a l (1961) s t a t e t h a t t h r e e rams (6-8 years) weighed 184 - 220 l b s . (86-100 kg.), and f i v e females weighed 101 - 119 l b s . (46.9 - 54 k g . ) . A very l a r g e ram weighed i n e a r l y f a l l 281 l b s . (128.4 k g . ) . R e l i a b l e weights are s u r p r i s i n g l y r a r e f o r e i t h e r d a l l i or s t o n e i . Ulmer (1941) r e p o r t s the weights of f o u r D a l l ' s rams as 173 - 185 l b s . These were o l d rams weighed s h o r t l y a f t e r death. A seven year o l d Stone's ram shot d u r i n g the r u t weighed 170 l b s . , but the animal was i n poor c o n d i t i o n . A s i x year o l d D a l l ' s ram shot i n e a r l y f a l l weighed 226 l b s . The l a r g e s t Stone's ram which I shot would have weighed about 250 l b s . l i v e weight. Although very s i m i l a r i n s i z e to d a l l i and s t o n e i . sheep of the n i v i c o l a group appear to have s m a l l e r horns. T h i s i s expected. Geptner et a l (1961) g i v e as maximum dimensions f o r n i v i c o l a a horn l e n g t h of 111 cm. (43"), and a b a s a l circumference of 36 c m . (14-1/4"). C l a r k (1964) i n h i s p a t i e n t search uncovered a good number of horn measurements f o r n i v i c o l a . The l o n g e s t h o r n l e n g t h he r e p o r t s i s 41-1/2"; the l a r g e s t b a s a l circumference as 14-1/2". These maxima f a l l w e l l below those of d a l l i and s t o n e i . The l o n g e s t h o r n l e n g t h r e c o r d e d f o r d a l l i exceeds 49", and f o r s t o n e i 51". Although d a l l i and s t o n e i are b e t t e r sampled than n i v i c o l a i n t h i s r e s p e c t , t h e r e does seem t o be a r e a l d i f  f e r e n c e h e r e . C e r t a i n l y b a s a l circumference w e l l beyond 15" has been r e p e a t e d l y r e p o r t e d f o r both d a l l i and s t o n e i . (see Anonymous, Records of North American B i g Game). N i v i c o l a i s a l s o p r i m i t i v e i n h a v i n g a small rump pat c h which does not extend beyond the r o o t of the t a i l (Lydekker 1898, C l a r k 1964), and i n h a v i n g o n l y very l i t t l e white on the r e a r margins of f r o n t and h i n d l e g s ( F i g . 101). Otherwise, one would be o c c a s i o n a l l y hard p r e s s e d to d i s  t i n g u i s h between i t and Stone's sheep. The c o l o u r and shade p a t t e r n i n g of both races appear to be s i m i l a r . Lydekker (1898) r e p o r t s t h a t n i v i c o l a has s h o r t e r ears than other American sheep. However, Geptner et a l (1961) l i s t the ear l e n g t h f o r males as 9 - 9.5 cm (3-1/2 - 3-3/4") and f o r females as 8 - 9 cm ( 3 - l / 4 - 3-1/2"), and t h i s i s the same as f o r Stone's sheep. Two rams had ears 3-3/4" long; one e x c e p t i o n a l l y l a r g e female had ears a l s o 3-3/4" l o n g (measured from the n o t c h ) • 130 In North America, the old. A l a s k a refugium i s p r e s e n t l y occupied by the white D a l l ' s sheep; i t i s p o s s i b l e t h a t the northernmost S t o n e ' s — t h e patchy, gray " f a n n i n " sheep of the Y u k o n — a r e a l s o found i n the e a s t e r n end of the refugium. In the o l d southern refugium we f i n d a number of canadensis r a c e s , of which the most p r i m i t i v e i s Nelson's sheep ( n e l s o n i ) . Cowan (1940) p o i n t e d out t h a t t h i s race had i t s c r a n i a l and horn c h a r a c t e r i s t i c s i n c l o s e a f f i n i t y w i t h those of the n o r t h e r n sheep from A l a s k a and the Yukon. From the Records of North American B i g Game I took the f i r s t 30 horn base circumferences of rams shot i n Nevada. They had circumferences of 14.2 + 0.85 (S.D.) in c h e s (12.0 - 16.0). The f i r s t 30 circumferences of d a l l i measured 13.7 + 0.56" (13.0 - 15.7). These f i g u r e s must be compared w i t h c a u t i o n s i n c e many more d a l l i are shot and r e c o r d e d than n e l s o n i . and the d a l l i r e  corded here may be h e a v i e r i n horns than i f samples were t r u l y random. N e v e r t h e l e s s , n e l s o n i , i n agreement w i t h the h y p o t h e s i s , i s a l i t t l e l a r g e r i n t h i s parameter than d a l l i and the d i f  f e r e n c e i s s i g n i f i c a n t a t the 5% l e v e l . We cannot compare the coat p a t t e r n of the white D a l l ' s sheep w i t h t h a t of the Nelson's b i g h o r n . However, s t o n e i and n e l s o n i appear to have much the same rump patch s i z e and shape. Stone's sheep have more white on t h e i r l e g s than n e l s o n i . Otherwise there i s l i t t l e s i m i l a r i t y i n coat c o l o u r or p a t t e r n i n g between the two forms ( F i g . 1.15). 131 Nelson's b i g h o r n appears to be more s i m i l a r i n b o d y s i z e to d a l l i than to o t h e r b i g h o r n r a c e s . Welles and Welles (1961) l i s t the average weight of 37 rams at 156 l b s . (127 - 190 l b s . ) and of 15 ewes a t 96.5 l b s . (74 - 114 l b s . ) . They are hence about as l a r g e as small Stone's sheep of equal sex and age. We hence f i n d , as a n t i c i p a t e d , sheep w i t h i n c r e a s i n g l y h e a v i e r and t h i c k e r horns and l a r g e r rump patches as we move from S i b e r i a , v i a A l a s k a t o the c e n t r e of the American southern refugium. Two c h a r a c t e r s do not change as expected. E a r l e n g t h does not decrease, r a t h e r i t appears to f o l l o w Bergmann's r u l e . Sexual dimorphism appears to be s i m i l a r between n i v i c o l a . d a l l i and Ovis canadensis n e l s o n i . As i n d i c a t e d b e f o r e , i f sheep changed when they c o l o n i z e d the once g l a c i a t e d areas, then those forms which are now found t h e r e are more advanced than those i n the refugium. We have u n f o r t u n a t e l y no i n f o r m a t i o n about the n i v i c o l a r a c e s i n t h i s r e s p e c t , however, i n North America t h i s i s what i s found. Prom the southern refugium, canadensis moved n o r t h , deep i n t o f o r m e r l y g l a c i a t e d r e g i o n s . T h i s race has much l a r g e r horns, rump patch s i z e and sexual dimorphism than n e l s o n i . The f i r s t 30 canadensis rams from A l b e r t a and B r i t i s h Columbia (the n o r t h e r n p a r t of t h e i r d i s t r i b u t i o n ) l i s t e d i n the Records of North American B i g Game, have a b a s a l horn circumference of 15.6 + 0.61 (S.D.) inches (14.3 - 17.0). T h i s i s 1.4" more than f o r n e l s o n i . however, t h i s d i f f e r e n c e i s most l i k e l y 132 exaggerated due to more canadensis rams being shot than n e l s o n i ; the d i f f e r e n c e i s s i g n i f i c a n t a t the 0.1$ l e v e l . The rump patch o f canadensis extends h i g h e r up on the rump, the corner has been rounded out and lowered, while the d o r s a l s t r i p e b i s e c t i n g the rump pa t c h has been reduced and p a r t i a l l y l o s t . A s c r u t i n y of 95 bighorns from B a n f f park, showed t h a t i n 70 the t a i l s t r i p e had been l o s t or p a r t i a l l y i n t e r  r u p t e d . Here I d i f f e r from Cowan (1940), who s t a t e s t h a t the m i d - d o r s a l l i n e f o r canadensis i s u s u a l l y extended to the t a i l b i s e c t i n g the rump patch. B i g rams i n what must be very h e a l t h y p o p u l a t i o n s can grow very l a r g e . Cowan (1940) c i t e s l i v e weights o f 285-344 l b s . f o r f o u r rams o l d e r than f i v e years of age shot i n B r i t i s h Columbia. These must be c o n s i d e r e d as maximum weights. Sheep from d i f f e r e n t p o p u l a t i o n s d i f f e r i n s i z e and so a p p a r e n t l y do sheep from the same p o p u l a t i o n i n d i f f e r e n t decades. When rams grow as l a r g e as those mentioned above they weigh 2 - 2-1/2 times as much as females; i n n e l s o n i t h i s r a t i o i s o n l y about 1.5 - 1.6. A t t h i s p o i n t l e t us note the f o l l o w i n g . I f sheep ev o l v e d i n e x t e r n a l appearance i n the d i r e c t i o n s d i s c u s s e d whenever they invaded r e g i o n s vacated by g l a c i e r s , then we should f i n d more advanced sheep not o n l y i n l a t i t u d e s vacated by g l a c i e r s , but a l s o i n a l t i t u d e s vacated by g l a c i e r s . Vegeta t i o n l i n e s are a l t i t u d e - d e p e n d e n t . The warmer i t got a f t e r g l a c i a l r e t r e a t , the h i g h e r d i d v e g e t a t i o n l i n e s spread, and the more h a b i t a t became a v a i l a b l e to sheep. B e f o r e l e a v i n g 133 the canadensis group, i t may he p o i n t e d out t h a t n e l s o n i i s surrounded hy advanced sheep. There i s v i r t u a l l y a r i n g of e v o l v e d forms about t h i s p r i m i t i v e r a c e . L i k e the n o r t h e r n canadensis. H» these r a c e s have l a r g e r rump patches and h e a v i e r horns, I t appears then t h a t the present canadensis races were d e r i v e d from a sma l l r e l i c p o p u l a t i o n which s u r v i v e d the h e i g h t of the l a s t g l a c i a t i o n a t low e l e v a t i o n s somewhere i n southern C a l i f o r n i a . D u r i n g the dry p e r i o d f o l l o w i n g the g l a c i a l withdrawals, sheep spread i n t o the i n h a b i t a b l e uplands. The r a c e which moved f u r t h e s t , canadensis, e v o l v e d the g r e a t e s t d i f f e r e n c e s from n e l s o n i . From the A l a s k a refugium, sheep moved south i n t o the A l a s k a and S t . E l l i a s range, n o r t h i n t o the Brooks range, while Stone's sheep moved southeast deep i n t o f o r m e r l y g l a c i a t e d t e r r a i n . As expected, the Stone's sheep i s l a r g e r i n h o r n s i z e and i n the upper p a r t s of the s k u l l than D a l l ' s sheep (Cowan 1940). The f i r s t 30 Stone's rams l i s t e d i n the Records of North American B i g Game have a b a s a l horn circum f e r e n c e of 14.5 + 0.58 (S.D.) inches (13.8 - 15.8). T h i s i s 0.8" more than d a l l i and i s s i g n i f i c a n t at the 0.1$ l e v e l . S i n c e s t o n e i and d a l l i are both hunted f r e q u e n t l y , these measurements appear t o be q u i t e v a l i d . The southernmost ~ Stone's sheep are probably a l s o l a r g e r i n b o d y s i z e than D a l l ' s sheep, however, t h i s remains to be v e r i f i e d . However, the o r i g i n of s t o n e i i s p r o b l e m a t i c . I t appears most u n l i k e l y t h a t the white d a l l i form c o u l d have 134 g i v e n r i s e t o s t o n e i * Cowan (p e r s o n a l communication) sug g e s t e d t h a t d a l l i and canadensis met i n an i n t e r g l a c i a l p e r i o d , and s t o n e i r e p r e s e n t s the s t a b i l i z e d outcome of a n c i e n t i n t e r g r a d a t i o n between the two. A l t e r n a t i v e l y , s t o n e i may be from a r e l i c d a l l i p o p u l a t i o n which s t i l l r e t a i n e d the n i v i c o l a c o l o u r a t i o n . T h i s r e l i c group s u r v i v e d i n the e a s t e r n p a r t s of the A l a s k a refugium and spread south e a s t i n post g l a c i a l times* Stone's sheep are more p r i m i t i v e than canadensis by h a v i n g s m a l l e r horn bases and a s m a l l e r rump p a t c h . However, they are so u n l i k e bighorns i n coat p a t t e r n t h a t only an experimental c r o s s between d a l l i and canadensis w i l l suggest whether the h y p o t h e s i s expressed by Cowan i s t e n a b l e . The c h a r a c t e r i s t i c s which d i s t i n g u i s h the d a r k e r , southern Stone's sheep from the " f a n n i n s " of the Yukon c o u l d w e l l have been evolved independently. There i s a l s o l i t t l e doubt t h a t dark and l i g h t D a l l ' s sheep met and c r o s s e d i n e a r l y post Wisconsin times (Sheldon 1911, i n Cowan 1940). Today, with sheep i n the North t o r n i n t o s e p a r a t e , o f t e n r e l i c p o p u l a t i o n s , I c o n s i d e r such c o n t a c t as u n l i k e l y . In g e n e r a l i t t h e r e f o r e appears t h a t A s i a t i c sheep and American sheep have shown p a r a l l e l s i n t h e i r e v o l u t i o n . In b o t h i n s t a n c e s , the concept t h a t sheep e v o l u t i o n was l i n k e d to range e x t e n s i o n a f t e r g l a c i a l r e t r e a t , i s f r u i t f u l . T h i s concept appears t o be e q u a l l y a p p l i c a b l e t o other c a p r i d s . Thus Pseudois. Ammotragus and Capra c y l i n d r i c o r n i s share many s i m i l a r i t i e s i n appearance. I f Ammotragus - l i k e 135 a n c e s t o r s gave r i s e to the o t h e r forms, these should have e v o l v e d s i m i l a r l y to sheep. Pseudois and C. c y l i n d r i c o r n i s are now found i n areas which were e i t h e r g l a c i a t e d or r e l a  t i v e l y b a r r e n d u r i n g the P l e i s t o c e n e . Indeed, great s i m i l a r i  t i e s to sheep e v o l u t i o n do e x i s t . Both forms have l a r g e r , h e a v i e r horns than Ammotragus; both l o s t the d o r s a l h a i r r i d g e on the neck, the cheek beards and neck r u f f ; C. c y l i n d r i c o r n i s has o n l y a t i n y c h i n beard; both evolved a rump p a t c h . Pseudois has a l a r g e rump patch and much white on the l e g s . C. c y l i n d r i c o r n i s has l e s s rump-and l e g marking but i t i s there (see P e t z s c h 1958). Sexual dimorphism has i n c r e a s e d i n both forms. Pseudois i s s h e e p - l i k e i n t h a t males are s o c i a l , and t h a t i t has e i t h e r v e s t i g e s or the beginnings of p r e o r b i t a l and i n t e r d i g i t a l g l a n d s . Pseudois i s f u r t h e r removed from an Ammotragus-1ike a n c e s t o r from North A f r i c a than C. c y l i n d r i c o r n i s f and has a l s o changed more i n the same d i r e c t i o n s as sheep. In these forms, the horn winding remained heteronym u n l i k e the homonym winding of advanced sheep, and t h e i r ears remained l o n g and p o i n t e d , not rounded as i n sheep. T h i s i n d i c a t e s t h a t i n c r e a s e i n h o r n s i z e need not be l i n k e d t o the homonym w i n d i n g ' l a t t e r hence e v o l v e d i n sheep f o r reasons ot h e r than i n c r e a s i n g horn mass. The e a r s — a s i n American s h e e p — a p p e a r independent of s e l e c t i o n f o r l a r g e r horns, l o s s of d i s p l a y h a i r s , e t c . The l a s t c a p r i d s t o be c o n s i d e r e d are of the genus Capra. I t i s not my aim t o t a c k l e the phylogeny of t h i s 136 group of s p e c i e s of obscure o r i g i n . I o n l y want to p o i n t out t h a t the s p e c i e s with the l a r g e s t horns, l e a s t d i s p l a y h a i r and g r e a t e s t sexual dimorphism are found deep i n the r e g i o n s g l a c i a t e d d u r i n g the P l e i s t o c e n e . These are the l a r g e ibexes (Capra i b e x ) . The southern ibex from A r a b i a and E t h i o p i a , may be l i v i n g today i n r e g i o n s which were d u r i n g g l a c i a t i o n w e l l above v e g e t a t i o n l i n e and hence b a r r e n and u n i n h a b i t a b l e . Changes i n the behaviour of c a p r i d s The d i s c u s s i o n has so f a r r e v o l v e d about m o r p h o l o g i c a l changes i n the e v o l u t i o n of sheep. T h i s s e r v e d t o form a model by which t o compare b e h a v i o u r a l changes. Presumably, m o r p h o l o g i c a l l y p r i m i t i v e forms have a l s o p r i m i t i v e behaviour. I hope to show l a t e r t h a t i t i s the behaviour of c a p r i d s which e x p l a i n s t h e i r changes i n e x t e r n a l appearance. U n f o r t u n a t e l y , we know l i t t l e about the behaviour of most c a p r i d s and are w e l l informed o n l y on the American sheep. Good o b s e r v a t i o n s are a v a i l a b l e f o r Ammotragus (Katz 1949, Haas 1958, Ogren 1965) and the r u p i c a p r i d s Oreamnos (Brandborg 1955), ( G e i s t 1964) and Rupicapra (Zedwitz 1937, Walther 1961). Walther (1961) r e p o r t e d important o b s e r v a t i o n s on c a p t i v e 0. a. p o l i . 0. c y c l o c e r o s f Capra ibex and C. f a l c o n e r i . I n c i d e n t a l behaviour and o b s e r v a t i o n s are s c a t t e r e d i n the c a p r i d l i t e r a t u r e . Banks (1964) gave good d e s c r i p t i o n s of the b e h a v i o u r p a t t e r n s of domestic sheep. The b e s t behaviour i n f o r m a t i o n i s hence a v a i l a b l e f o r the h i g h e s t evolved forms 137 and the q u i t e p r i m i t i v e ones. However, s i n c e we do have a model of sheep e v o l u t i o n based on m orphological c h a r a c t e r s , we can form some c o n c l u s i o n s about t h e i r b e h a v i o u r a l e v o l u t i o n . (1) I t appears t h a t sheep evolved from a g e n e r a l i z e d , damaging combat type of t h e i r r u p i c a p r i d a n c e s t o r s , t o . r i t u a l i s e d , r e l a t i v e l y harmless combat form. They s p e c i a l i z e d i n c r e a s i n g l y i n the c l a s h , i n which they i n i t i a l l y f o c u s e d the f o r c e of the c o l l i s i o n on one horn k e e l (p. 50 ), and reduced o t h e r f i g h t i n g forms t o i n s i g n i f i c a n c e . The v i c i o u s f i g h t c h a r a c t e r i s t i c of a n c e s t r a l p r i m i t i v e forms has not been l o s t e n t i r e l y . (2) The c h i e f defense a g a i n s t the opponents blows changed from a t h i c k h i d e , avoidance of combat by v i r t u e of withdrawal or d i s p l a y , t o c a t c h i n g the blows with the horned head. I t i s t h i s change which a l l o w e d the e v o l u t i o n of the c l a s h , and the f r e q u e n t occurrence of combat which i s r e l a t i v e  l y harmless w i t h the new defense mechanism. C o n c u r r e n t l y with the e v o l u t i o n of r i t u a l i s e d c l a s h i n g the h i d e became t h i n n e r . (3) With the e v o l u t i o n of l a r g e horns and l o s s of l o n g body h a i r , the b r o a d s i d e d i s p l a y disappeared and was r e p l a c e d by a horn d i s p l a y . The horns, b e s i d e s a c t i n g as weapons and s h i e l d , now have the a d d i t i o n a l f u n c t i o n s of d i s p l a y organs and rank symbols ( G e i s t 1966). D i f f e r e n t s i z e s of horns probably produce a d i f f e r e n t f o r c e of impact d u r i n g the c l a s h (p. 53 ), and, s i n c e the c l a s h i s u s u a l l y f o l l o w e d by a horn d i s p l a y , a l l o w combatants to a s s o c i a t e c l a s h f o r c e 138 with horn s i z e . I t i s t h i s which a l l o w s horns t o f u n c t i o n as rank symbols, and probably s e l e c t s f o r frequent horn d i s p l a y . I t i s advantageous t o show horns t o a subordinate, as t h i s would r e i n f o r c e the a s s o c i a t i o n between horn s i z e and c l a s h f o r c e . In the rush-and horn t h r e a t sheep remained conserva t i v e ; these t h r e a t s are q u i t e s i m i l a r t o those of Oreamnos ( G e i s t 1964). The threat-jump however, i s s p e c i a l i z e d s i n c e i t i s r e a l l y the i n t e n t i o n movements, or p r e p a r a t o r y behaviour of the c l a s h . However, Oreamnos.which does not c l a s h , o c c a s i o n a l l y a l s o threat-jumps to an opponent by jumping up i n f r o n t and h i t t i n g (throwing) backwards w i t h the head. R u p i c a p r i d males may perform r a t h e r exuberant jumping and f r o l l i c k i n g i n which t h r e a t jump-like behaviour does occur (Walther 1961). Hence, the p r e r e q u i s i t e s f o r the s p e c i a l i z e d t h r e a t jumps of jO. canadensis, d a l l i . p o l i and Capra males are a l r e a d y present i n the r u p i c a p r i d stem. (4) With i n c r e a s e d sexual dimorphism, the c o u r t s h i p of the l a r g e r males became more f o r c e f u l while the female be came l e s s a g g r e s s i v e . T h i s devlopment i s made p o s s i b l e by the absence of sharp horns and the e v o l u t i o n of b u t t i n g and c l a s h  i n g . Whereas the Oreamnos female i s a very dangerous opponent ( G e i s t , i n p r e s s ) , the female mountain sheep poses no t h r e a t t o the ram. I t seems t o f o l l o w t h a t c a u t i o u s c o u r t s h i p would be s e l e c t e d f o r i n Oreamnos males s i n c e i t would reduce the chances of the male b e i n g a t t a c k e d and wounded by the female, 139 whereas t h e r e would he l i t t l e s e l e c t i o n a g a i n s t v i g o r o u s c o u r t s h i p hy the ram. The c o u r t s h i p behaviour of c a p r i d s has otherwise remained c o n s e r v a t i v e (see Walther 1961, Haas 1958). (5) D u r i n g c a p r i d e v o l u t i o n , males changed from b e i n g s o l i t a r y to b e i n g g r e g a r i o u s and f i n a l l y s o c i a l forms. I t appears t h a t t h i s was made p o s s i b l e by the e v o l u t i o n of r e l a t i v e l y harmless forms of combat which p e r m i t t e d the establishment and maintenance of dominance h i e r a r c h i e s v i a f r e q u e n t a g o n i s t i c i n t e r a c t i o n s . Conspicuous h o r n s i z e d i f  f e r e n c e s among males a l l o w a p r i o r i p r e d i c t i o n o f dominance r e l a t i o n s h i p s , hence i n d i v i d u a l rams l i v e i n a f a m i l i a r s o c i a l environment even though they meet s t r a n g e r s . Although such mechanisms probably allowed the males to l i v e g r e g a r i o u s l y , they were not the cause f o r the males keeping t o g e t h e r . T h i s w i l l be d i s c u s s e d l a t e r (see neoteny p.144 ). These are some of the major b e h a v i o u r a l changes which appear to have happened ;. i n the e v o l u t i o n of sheep, and pro b a b l y other c a p r i d s . I t was noted t h a t s e v e r a l l i n e a g e s o f sheep and goats e v o l v e d s i m i l a r e x t e r n a l f e a t u r e s c o n v e r g e n t l y . I t would t h e r e f o r e not be s u r p r i s i n g i f such end products o f e v o l u t i o n as the a r g a l i s or b i g h o r n s , Pseudois or Capra ibex have e v o l v e d s i m i l a r i t i e s i n t h e i r b e h a v i o u r . Thus Walther's (1961) o b s e r v a t i o n s on c a p t i v e p o l i show t h a t t h e i r behaviour i s v e r y s i m i l a r to t h a t of American sheep. The p o l i ram used the l o w - s t r e t c h o f t e n , he c l a s h e d a f t e r a b i p e d a l r u n h o l d i n g h i s head, l e g s and body l i k e a b i g h o r n or Stone's ram. H i s 140 c l a s h e s appeared t o be s i m i l a r i f not i d e n t i c a l with those of bighorns (Walther 1961), and l i k e the' l a t t e r ;he: c a r r i e d a prominent l a t e r a l edge on the horns. The p o l i ram pawed ex u b e r a n t l y d u r i n g s o c i a l i n t e r a c t i o n s , which i s a l s o d o n e — b u t r a r e l y — b y t h i n horn sheep. The s i m i l a r i t y extends i t s e l f a l s o i n t o c o u r t s h i p b e h a v i o u r . I t i s the more remark a b l e s i n c e the behaviour of p o l i and c v c l o c e r o s — b o t h from the ammon c l i n e — i s q u i t e d i f f e r e n t . The c y c l o c e r o s ram (probably from P a k i s t a n ) which Walther (1961) observed, d i d not h o l d the low s t r e t c h , but he d i d perform .an exuberant t w i s t and o n l y then momentarily dipped i n t o the low s t r e t c h . In t h i s , domestic sheep t e n d t o resemble the u r i a l s r a t h e r than the advanced sheep (see Banks 1964). When c l a s h i n g , the c y c l o c e r o s ram charged on a l l f o u r s l i k e a mouflon or domestic sheep. Walther (1961) noted t h a t the ram may l i f t the f r o n t l e g s o f f the ground an i n s t a n t b e f o r e the c l a s h . In t h i s c l a s h type c y c l o c e r o s appears t o be advanced over Ammotragus. but more p r i m i t i v e than e i t h e r the a r g a l i s or b i g h o r n s . T h i s i s more or l e s s what c o u l d be expected s i n c e c y c l o c e r o s i s i n termediate i n e x t e r n a l c h a r a c t e r i s t i c s between Ammotragus and 0. a. p o l i . The advanced goats are s i m i l a r t o advanced sheep i n t h a t they use a b i p e d a l c l a s h . However, o u t s i d e the b i p e d a l stance t h e r e i s l i t t l e s i m i l a r i t y i n the c l a s h form. Pseudois. Capra i b e x , c y l i n d r i c o r n i s . aegagrus and f a l c o n e r i a l l c l a s h b i p e d a l l y . 141 The r u p i c a p r i d s Oreamnos and Rupicapra have a b r o a d s i d e p r e s e n t - t h r e a t as has Hemitragus. American sheep have r e p l a c e d the b r o a d s i d e d i s p l a y with horn d i s p l a y s . The l a r g e horned European and S i b e r i a n ibexes observed by Walther (1961) appeared to possess no b r o a d s i d e d i s p l a y . However, the markhor, e q u a l l y l a r g e horned to ibex but covered with l o n g d i s p l a y h a i r s , has a b e a u t i f u l b r o a d s i d e d i s p l a y . In t h i s d i s p l a y i t e r e c t s the l o n g h a i r s on i t s d o r s a l l i n e . The markhor i s i n t h i s r e s p e c t somewhat p r i m i t i v e . I t has a l s o a more p r i m i t i v e t o o t h s t r u c t u r e than ibex or aegagrus, i n r e t a i n i n g r e l a t i v e l y l a r g e premolars (see Geptner et a l 1961. F i g . 179). I t appears t h a t i n the most advanced, long-horned c a p r i d s , which have l o s t t h e i r d i s p l a y h a i r s , the b r o a d s i d e d i s p l a y i s l o s t and the horns assume d i s p l a y f u n c t i o n . Bighorn sheep as w e l l as Walther*s (1961) p o l i ram d i s p l a y e d horns from the l o w - s t r e t c h and head h i g h ("present") p o s i t i o n s . The r a t h e r h a i r y c y c l o c e r o s ram appeared to know n e i t h e r the l o w - s t r e t c h nor the p r e s e n t . I t i s q u i t e l i k e l y t h a t u r i a l s as w e l l as Ammotragus have r e t a i n e d some semblance of a b r o a d s i d e d i s p l a y . These o b s e r v a t i o n s s u b s t a n t i a t e the concept that b e h a v i o u r a l changes have p a r a l l e l e d m o r p h o l o g i c a l ones i n the e v o l u t i o n of c a p r i d s . Thus the i n c r e a s e i n h o r n s i z e , l o s s of d i s p l a y h a i r s , and i n c r e a s e i n rump patch s i z e appeared to go hand i n hand with the s p e c i a l i z a t i o n of a b i p e d a l c l a s h , r e d u c t i o n and l o s s of b r o a d s i d e d i s p l a y , and the e v o l u t i o n of horn d i s p l a y s . 142 Neoteny as a f a c t o r In sheep b i o l o g y A. number of f e a t u r e s i n the behaviour and appearance of sheep can be e x p l a i n e d by the hy p o t h e s i s t h a t the male i s n e o t e n i c but reaches an u l t i m a t e a d u l t form, whereas the female i s a paedogenic form which remains j u v e n i l e i n ap pearance and behaviour throughout l i f e . I am u s i n g here the d e f i n i t i o n s o f n e o t e n i c and paedogenic as formed by Romer (1956). Amongst mammals we do not f i n d l a r v a l forms but we do f i n d j u v e n i l e forms, and with t h i s minor m o d i f i c a  t i o n Garstang's concept becomes a p p l i c a b l e t o mammals. Males of American sheep mature s e x u a l l y at l - l / 2 - 2-1/2 years of age, but they are not mature b e h a v i o u r a l l y , nor do they reach u l t i m a t e body p r o p o r t i o n s u n t i l they are 7 - 8 years o l d . The changes i n horn and body p r o p o r t i o n s are d i s c u s s e d (p. 10 ) . Few weights and measurements are a v a i l a b l e f o r rams of v a r i o u s ages, however, i t i s apparent t o the unaided eye t h a t they grow b u l k i e r u n t i l they are about 7 years o l d . C h e r n i a v s k i * s (1962) data f o r n i v i c o l a i n d i c a t e s i n c r e a s e s i n weight by a d u l t rams u n t i l they are 9 - 1 0 years o l d . Hence, growth continues l o n g a f t e r sexual m a t u r a t i o n . As lambs, rams show no d i s p l a y s nor any ru b b i n g or h o r n i n g on other lambs, but do c l a s h , b u t t , horn t h r e a t and t h r e a t jump or, f r e q u e n t l y mount other lambs. T h e i r a c t i o n s are almost e n t i r e l y a g g r e s s i v e or s e x u a l . As rams mature, they become i n c r e a s i n g l y l e s s l i k e lambs, by u s i n g fewer a g g r e s s i v e p a t t e r n s or mountings ( F i g . 102) and more and more d i s p l a y p a t t e r n s l i k e the f r o n t - k i c k ( F i g . 103A), t w i s t ( F i g . 103B) or l o w - s t r e t c h ( F i g . 104B). Rams a l s o undergo 143 a p s y c h o l o g i c a l m a t u r a t i o n . I t i s shown i n F i g . 104A t h a t rams approach t h e i r own s i z e c l a s s w i t h i n c r e a s i n g frequency i n l o w - s t r e t c h as they grow o l d e r and l a r g e r . S ince the l o w - s t r e t c h approach i s t y p i c a l of dominants, the ram a c t s w i t h i n c r e a s i n g frequency as i f he were the dominant i n the f a c e of equal s i z e d companions. I t may be t h a t equal s i z e d opponents appear l e s s f o rmidable to them. In t h i s case we expect i n t e r a c t i o n s t o become more fre q u e n t and i n t e n s e as rams grow o l d e r . T h i s i s borne out i n F i g . 104 and 106; the former remains to be t e s t e d . I t i s hence e v i d e n t t h a t rams not o n l y grow, but a l s o change b e h a v i o u r a l - l y a f t e r sexual m a t u r a t i o n . They are b e h a v i o u r a l l y mature about the same time t h a t they r e a c h u l t i m a t e body p r o p o r t i o n s which i s at 7 - 9 years of age. The ewe i s paedogenic s i n c e she never reaches the u l t i m a t e growth form, but remains throughout l i f e the very image of a s e x u a l l y mature y e a r l i n g ram. They are so s i m i l a r i n body and horn s i z e , f a c i a l f e a t u r e s and b e l l y marking (p« 12 F i g * 8) as to be e a s i l y confused even by experienced o b s e r v e r s . The ewe i s s i m i l a r — t h o u g h not i d e n t i c a l — t o young males i n her s o c i a l b e h a v i o u r . L i k e these, ewes d i s p l a y l i t t l e and r a r e l y rub or n u z z l e other sheep, at l e a s t not u n t i l they are i n e s t r u s . Ewes use mainly a g g r e s s i v e p a t t e r n s ( F i g . 71 c ) . When ewes are i n e s t r u s , they behave towards the guarding ram as do subordinate rams t o dominant ones (p. 115 ), and are t r e a t e d l i t t l e d i f f e r e n t l y i n r e t u r n . Non-estrus ewes a c t much l i k e lambs or subadult ewes i n t h e i r response to the f r o n t - k i c k or mount ( F i g . 7 7 ) . A c h a r a c t e r i s t i c of lambs 144 i s t h a t they f o l l o w other sheep and are hence r a r e l y seen a l o n e . T h i s i s e q u a l l y t r u e f o r ewes and j u v e n i l e rams. In t h i s , these two c l a s s e s resemble each other more,* than e i t h e r does o l d e r rams (Table I I ) . L i k e other i n f a n t s of s o c i a l ruminants such as e l k (Altmann 1963) or c a t t l e ( S c h l o e t h 1961), lambs tend t o form j u v e n i l e groups w i t h i n female bands. They appear t o fav o u r the company of equals, but f o l l o w a d u l t s once these move on. These two t e n d e n c i e s — t o a s s o c i a t e with equals and to f o l l o w an " a d u l t " — e x p l a i n the a c t i o n s of young rams. When rams are t h r e e y ears o l d , they are l a r g e and q u i t e d i s t i n c t from females. They now b e g i n t o a s s o c i a t e w i t h other rams of equal or s i m i l a r s i z e o u t s i d e the female band. When on the move, these young rams f o l l o w the l a r g e s t horned or one of the l a r g e s t horned rams i n the band (Table I I I ) . At t h a t stage, young rams are more " a d u l t " i n appearance than ewes; the most " a d u l t " l o o k i n g sheep f o r these young rams would be rams which had reached the u l t i m a t e growth form ( C l a s s I V ) . Hence, the young rams o n l y c o n t i n u e d d o ing what lambs d i d — t h e y a s s o c i a t e d with equals but f o l l o w e d an " a d u l t " . As rams grow o l d e r , they begin to l o s e these j u v e n i l e t e n d e n c i e s . T h i s i s i n d i c a t e d i n t h a t they are seen more f r e q u e n t l y without company. Table I I shows t h i s t r e n d i n a dense b i g h o r n p o p u l a t i o n ; F i g . 96 shows i t much more c l e a r l y f o r Stone's sheep i n a sparse p o p u l a t i o n . These data i n d i c a t e t h a t rams become more independent of other sheep w i t h age. 145 S i n c e o l d e r rams l o o k more " a d u l t " younger rams f o l l o w them; s i n c e they act more a d u l t hy b e i n g independent they l e a d . A f t e r a l l , a l e a d e r i s the most independent a c t i n g animal i n a group. The great sexual dimorphism of advanced c a p r i d s appear t o be a f u n c t i o n of the l o n g j u v e n i l e phase of the male. I f the male changes i n appearance due to growth v i a a p r o g r e s s i v e l y prolonged j u v e n i l e phase, while the female matures at 1-1/2 - 2-l/2 y ears of age and grows l i t t l e t h e r e a f t e r , then the female w i l l become p r o g r e s s i v e l y s m a l l e r and more j u v e n i l e compared t o the male. F o r rams, growth i n horn and body s i z e was p r e v i o u s l y l i n k e d t o j u v e n i l e n e s s . An i n c r e a s e i n horn mass can be a c h i e v e d not only by i n c r e a s i n g the number of growth years, or i n t e n s i f y i n g growth w i t h i n each year, but a l s o by s h i f t i n g most horn growth i n t o the l a t t e r p a r t of the j u v e n i l e stage. Here the horns are growing from a wider base, and hence become t h i c k e r and more massive. In t h i s r e s p e c t d a l l i and canadensis d i f f e r i n the growth p a t t e r n of the horn ( F i g . 105) the r e s u l t b e i n g a l a r g e r horn i n t h e l a t t e r . I f , however, l a r g e r horns grow on rams who p r o g r e s s i v e  l y become more j u v e n i l e , then they should a l s o p r o g r e s s i v e l y become more j u v e n i l e i n other f e a t u r e s . Thus the neck r u f f becomes i n c r e a s i n g l y reduced and f i n a l l y l o s t i n ammon sheep ( F i g . 9 8 ) . The r u f f i s o n l y found on s e x u a l l y mature rams and more p o o r l y developed i n young than i n the o l d rams (Lydekker 1913 p. 104). Hence, rams which grow more horn mass by becoming 146 p r o g r e s s i v e l y more j u v e n i l e , s h o u l d a l s o reduce the neck r u f f p r o g r e s s i v e l y and f i n a l l y l o s e i t . No s e l e c t i o n f o r c e s a g a i n s t the r u f f need to he p o s t u l a t e d . By the same l i n e o f r e a s o n i n g , sheep which grow h e a v i e r horns, should a l s o use the j u v e n i l e behaviour of b u t t i n g , c l a s h i n g and mounting r e l a t i v e l y more f r e q u e n t l y . Thus canadensis rams should use the p a t t e r n s more f r e q u e n t l y than d a l l i rams from comparable p o p u l a t i o n s . T h i s i s indeed what o c c u r s . I noted a great d i f f e r e n c e between the dense d a l l i p o p u l a t i o n I s t a y e d w i t h i n f a l l 1963, and the somewhat poorer q u a l i t y b i g h o r n p o p u l a t i o n from Banff Park. Bighorn rams c l a s h e d d a i l y , D a l l ' s rams I heard c l a s h very r a r e l y ; even b u t t i n g was uncommon. These bighorns c l a s h e d even more f r e q u e n t l y than the v i g o r o u s Stone's rams I observed. T h i s i s shown by the data i n Ta b l e IV. Although neoteny e x p l a i n s some of the f e a t u r e s of sheep, i t does not e x p l a i n every t h i n g . Why d i d sheep evolve the homonym winding of t h e i r horns? At present there i s no p l a u s i b l e e x p l a n a t i o n as to why they changed i n i t i a l l y from heteronym t o homonym winding ( F i g . 98), p r i m a r i l y because we do not know the behaviour of p r i m i t i v e u r i a l s . However, once the change i n hornwinding began, i t had to go on. Note t h a t the c i r c u l a r horns of the u r i a l s p o i n t d i r e c t l y at the ram's neck ( F i g . 9 8 ) . I f such sheep were s u b j e c t t o s e l e c t i o n f o r l o n g e r horns, rams would grow the horn t i p s i n t o t h e i r neck. 147 I f the t i p s miss the neck, then we get the f a m i l i a r homonym winding as we see i t i n the n o r t h e r n c y c l o c e r o s forms ( F i g . 98). The u r i a l s e v o l v e d a sharp angle on the l a t e r a l s i d e o f the horns. T h i s i n d i c a t e s t hat i n c l a s h i n g rams cock the head s l i g h t l y a n d — l i k e American s h e e p — h i t f i r s t w i t h one horn, c o n c e n t r a t i n g thereby the c l a s h f o r c e on one horn k e e l . The t r e n d f o r l o n g , t h i n angular horns continued as we move v i a s e v e r t z o v i and n i g r i m o n t a t o p o l i . Here, i n the Pamir a r g a l i , i t reached i t s maximum e x p r e s s i o n f o r p o l i grows the l o n g e s t horns of a l l sheep (up t o 75 i n c h e s ) . However, horns much l o n g e r than those of p o l i are not p o s s i b l e — a t l e a s t not with the manner i n which p o l i c l a s h e s . These rams c l a s h s i m i l a r l y to bighorns by r a c i n g b i p e d a l l y at the opponent, i n c l i n i n g the head s l i g h t l y away and down, hence b r i n g i n g one l a t e r a l hornedge forward f o r c l a s h i n g . I f two p o l i rams wi t h l a r g e horns were to c l a s h i n t h i s f a s h i o n , they almost i n e v i t a b l y would h i t t h e i r horn ends f i r s t . T h i s would l e a d to breakage of the r a t h e r l i g h t though l o n g h o r n s . T h i s happens i n b i g h o r n s . C l a r k (1964) i n h i s i n t e r e s t i n g account of p o l i i n the Russian Pamir r e p o r t e d the f o l l o w i n g : Hornbreakage among l a r g e p o l i rams was f r e q u e n t . U n l i k e b i g h o r n s , p o l i rams do not broom t h e i r horns but break them o f f u s u a l l y a t the end of the horncores, but o f t e n c l o s e r to the s k u l l . Although p o l i horns tend t o ^ be n e a r l y twice as l o n g as those of b i g h o r n s , and have s i m i l a r 148 circumferences at the base (55 - 75" l o n g , 14 - 16" c i r  cumference), they weigh no more than the horns of bighorns and o f t e n l e s s . C l a r k (1964) r e p o r t s the weight of the upper s k u l l and horns of a l a r g e p o l i ram as 25 l b s . I weighed the heads of e i g h t h e a v i l y broomed b i g h o r n rams, ages 8 - 1 6 years and o b t a i n e d a range of 20 - 32 l b s . , average 25.3 l b s . ( S k u l l and horns thoroughly d r y ) . C l a r k (1964) r e p o r t e d as maximum weight f o r s k u l l and horns of bighorns 40 l b s . T h i s i n d i c a t e s t h a t p o l i horns are r a t h e r l i g h t l y c o n s t r u c t e d . Horn f r a c t u r e s , appear t o me t o be s e r i o u s i n j u r i e s , i r r e s p e c t i v e of what consequences the broken horn has on the ram's s o c i a l s u c c e s s . I f the horn cores are i n j u r e d or f r o z e n d u r i n g winter, the door i s open f o r b a c t e r i a l a t t a c k of the membranes i n s i d e the horn s i n u s e s . I t seems to me t h a t s e l e c t i o n would a c t a g a i n s t p o l i rams with very l o n g horns. C l e a r l y , i f horns were t o evolve f u r t h e r some change had to appear. The change came i n the next member of the c l i n e to the n o r t h - e a s t of the Pamir, i n the L i t t e d a l e ' s sheep from the Tien-shan ( F i g . 98 & 99). The angle of the horn s h i f t s away from the eye towards the median l i n e of the s k u l l . T h i s can be seen p a r t i a l l y i n F i g . 98. I t i s best seen comparing i n C l a r k (1964) the p o l i ram p. 59, with l i t t e d a l e i p. 95 and k a r e l i n i p. 89. T h i s r e s u l t s i n a r i d g e which appears to run down the c e n t r e of the a n t e r i o r horn f a c e (see Lydekker 1913 F i g . 30). The i m p l i c a t i o n i s e v i d e n t . Rams with a more f r o n t a l l y l o c a t e d edge would probably c l a s h more f r o n t a l l y . T h i s would swing the horn t i p s away and reduce the chances of horn breakage d u r i n g the c l a s h . In the L i t t e d a l e ' s sheep the horns have a l s o i n c r e a s e d i n diameter and mass. 149 As we move f u r t h e r n o r t h - e a s t , the horn mass of a r g a l i s i n c r e a s e s s t e a d i l y . The s k u l l and horns o f a good p o l i weigh about 25 l b s . , but those o f a good ammon weighed 49 l b s . ( C l a r k 1964). While the weight of s k u l l and horns almost doubles, the body weight i n c r e a s e s only from about 300 - 350 l b s . t o 400 - 450 l b s . ( a f t e r C l a r k 1964, Geptner et a l 1961). Furthermore, the horn angle, so prominent i n ni g r i m o n t a or p o l i becomes l o s t as horns i n c r e a s e i n diameter i n ammon and d a r w i n i . A s i m i l a r r e l a t i o n s h i p e x i s t s a l s o i n the American sheep. The horns of s t o n e i rams I worked wi t h had prominent l a t e r a l horn angles; the upper s k u l l and horns o f f o u r rams ages 8 - 1 6 yea r s , weighed 16 - 22 l b s . , average 18 l b s . , while l i v e weight o f o l d rams would have been about 200-250 l b s . Northern canadensis rams, weighing about 300 l b s . l i v e weight had horns and s k u l l weights of about 25 l b s . , but r e a c h i n g o c c a s i o n a l l y more than 30 l b s . S i m i l a r t o ammon. canadensis rams have more rounded horns and though the horn k e e l i s present, i t i s not as prominent as i n t h i n horn sheep. On the b a s i s of neoteny, i t can be expected that S i b e r i a n a r g a l i s w i l l c l a s h more f r e q u e n t l y than the t h i n horned p o l i — j u s t as i t i s found i n American sheep. The d i f f e r e n c e s i n appearance o f the c a p r i d s are ap p a r e n t l y brought about by - a c c e l e r a t i o n , p r o l o n g a t i o n or r e t a r d a t i o n of the growth of d i f f e r e n t body p a r t s . These seem t o be s u p e r f i c i a l changes r a t h e r than fundamental ones, changes i n the c o n t r o l of genes r a t h e r than changes i n the fundamental gene c o n s t i t u t i o n . T h i s may be the reason why 150 genomes of d i f f e r e n t c a p r i d s p e c i e s are o f t e n compatible and v i a b l e h y b r i d s may be obtained. An e x p l a n a t i o n of the major s e l e c t i o n f o r c e s i n sheep e v o l u t i o n Although neoteny e x p l a i n s many f e a t u r e s of sheep e v o l u t i o n , i t f a i l s t o answer the most fundamental q u e s t i o n s . Why d i d these changes occur i n the f i r s t p l a c e ? What p o s s i b l e advantages d i d the advanced forms gain? Are not the s o c i a l a d a p t a t i o n s of the most p r i m i t i v e c a p r i d s j u s t as f u n c t i o n a l as those o f the most advanced? How do such geographic s e r i e s as t h a t of the ammon rac e s develop? Why have the more p r i m i  t i v e members f a i l e d to c a t c h up with the advanced forms? I b e l i e v e t h a t a t e n t a t i v e answer can be given t o these q u e s t i o n s . In an e a r l i e r paper ( G e i s t , i n p r e s s ) I p o i n t e d out t h a t horn s i z e of rams i s d i r e c t l y r e l a t e d t o dominance rank and b r e e d i n g s u c c e s s . Large horned rams d i d almost a l l the b r e e d i n g . T h i s i n d i c a t e s t h a t l a r g e horns are a d a p t i v e and t h a t rams w i t h v i g o r o u s horn growth w i l l breed more ewes w i t h i n one b r e e d i n g season, than s m a l l e r horned ( o c c a s i o n a l l y o l d e r ) c o m p e t i t o r s . However, rams wit h v i g o r o u s horn growth, which r e a c h h i g h dominance and b r e e d i n g s t a t u s e a r l y i n l i f e , a l s o t e n d to d i e e a r l i e r than rams with poor horn growth. Here i s a paradox. The success of any c h a r a c t e r i s t i c i s judged by the number of o f f s p r i n g i t s c a r r i e r s l e a v e behind. The v i g o r o u s , l a r g e horned ram i s c l e a r l y s u c c e s s f u l w i t h i n one r u t t i n g season. However, a ram w i t h somewhat poorer horns who i s 151 r e a s o n a b l y h i g h i n dominance, w i l l a l s o l e a v e some o f f s p r i n g from each r u t t i n g season. Due to l o n g e r l i f e expectancy, however, he may le a v e more o f f s p r i n g s t han the l a r g e r horned ram w i t h a s h o r t e r l i f e expectancy. Hence, the l o n g e r l i f e expectancy of s m a l l e r horned rams may very w e l l c a n c e l i n the l o n g run the r e p r o d u c t i v e advantage of long-horned rams. T h i s concept, I b e l i e v e t o be the key t o sheep e v o l u t i o n . We noted e a r l i e r , t h a t l a r g e horns appeared t o be products o f neoteny. T h i s i s the mechanism. N a t u r a l s e l e c t i o n f o r l a r g e horns i n sheep, would mean a s e l e c t i o n f o r t h i s mechanism. Though neoteny e x p l a i n s how horns can grow l a r g e , i t i s s e l e c t i o n f o r l a r g e horns which e x p l a i n s the e x i s t e n c e of neoteny. S e l e c t i o n f o r l a r g e horns w i l l occur whenever th e r e i s an abundance of rams which have grown c l o s e t o t h e i r g e n e t i c maximum. In such a p o p u l a t i o n , phenotypic s i z e v a r i a t i o n w i l l be reduced. Rams with poor horn growth w i l l be s e l e c t e d a g a i n s t not o n l y because they w i l l be l e s s success f u l each b r e e d i n g season, but because the presence of many l a r g e r rams c a n c e l s t h e i r advantage of l o n g e v i t y . E v o l u t i o n f o r l a r g e horns w i l l come t o an end when there i s an abun dance of g e n o t y p i c a l l y or p h e n o t y p i c a l l y small rams of l o n g l i f e expectancy. The former c o n d i t i o n should e x i s t i n the expanding, the l a t t e r i n the stagnent or d e c l i n i n g p o p u l a t i o n s . E a r l i e r , i t was noted t h a t sheep e v o l u t i o n appears t o be a s s o c i a t e d with g l a c i a t i o n . When the c o n t i n e n t a l g l a c i e r s 152 II . o f the Wurm (Wisconsin) g l a c i a t i o n r e t r e a t e d , they were f o l l o w e d hy a dry steppe w i t h some h i r c h and w i l l o w shrub i n moist s i t e s (Heusser 1965, B o n a t t i 1966). T h i s i s sheep h a b i t a t , much as i t i s found i n the S t . E l i a s range i n the Yukon today. Sheep moved i n t o t h i s new l i v i n g space, and the stage f o r expanding sheep p o p u l a t i o n was s e t . To the c o l o n i z i n g p o p u l a t i o n s f o r a g e would have been u s u a l l y abundant, even d u r i n g the c r i t i c a l l a t e w i n t e r months. The i n d i v i d u a l s would u s u a l l y have been i n good p h y s i c a l c o n d i t i o n . Under such circumstances, t h e r e would be h i g h r e p r o d u c t i o n (see K l e i n 1965), l a r g e , w e l l developed, v i g o r o u s lambs (Wallace 1948, S c h i n k e l and S h o r t 1961), low neonatal m o r t a l i t y (Gunn and Robinson 1963, Alexander and Peterson 1961, Pu r s e r and Young 1959), abundant m i l k supply f o r the lambs (Wallace 1948, Munroe 1962), hence great growth r a t e of lambs ( S l e n et a l 1963). The s u r v i v a l of lambs would most l i k e l y be good (see K l e i n 1965). The y e a r l i n g s would be of l a r g e body s i z e and would mature e a r l i e r as has been shown on sheep (Watson et a l 1956) and deer (Cowan et a l 1957, Wood et a l 1962). These sheep would be expected t o become l a r g e a d u l t s ( S c h i n k e l and Short 1961, K l e i n 1964). In s h o r t , the c o l o n i z i n g p o p u l a t i o n would be an expanding one i n which sheep reached l a r g e body s i z e and phenotypic s i z e v a r i a b i l i t y would be reduced. The behaviour of rams i n the c o l o n i z i n g p o p u l a t i o n , 153 would be i n p r i n c i p l e s i m i l a r t o t h a t of the Stone's sheep I s t u d i e d . I r e g a r d i t as a hi g h q u a l i t y p o p u l a t i o n s i n c e r e p r o d u c t i o n was high ( i n 1962, 18 from 20 known ewes l e d a lamb i n f a l l ) , the lambs s u c k l e d l o n g e r than b i g h o r n lambs from Banff at comparable age and terminated s u c k l i n g on t h e i r own i n about 10$ (n=84) of the s u c k l e s , which I never saw b i g h o r n lambs do. The Stone's y e a r l i n g rams were i n f a l l as l a r g e as ewes, dominated these, and p a r t i c i p a t e d i n the r u t . No b i g h o r n y e a r l i n g I observed i n B a n f f reached these c o n d i t i o n s . In the hi g h q u a l i t y p o p u l a t i o n one can expect more v i g o r o u s i n t e r a c t i o n s between rams than i n a s t a t i c or d e c l i n i n g one. The i n t e r a c t i o n s o f Stone's rams were more i n t e n s e than those of Banff b i g h o r n s . T h i s i s i n d i c a t e d by the l a r g e r number of p a t t e r n s d e a l t out per i n t e r a c t i o n between Stone's rams ( P i g . 103 & 106). I f m o r t a l i t y of rams i s l i n k e d t o the degree of exhaustion from f i g h t i n g and c o u r t i n g d u r i n g the r u t — a s i s i n d i c a t e d by the i n v e r s e r e l a t i o n s h i p between dominance and l i f e e x p e c t a n c y — t h e n rams from a v i g o r o u s p o p u l a t i o n should d i e younger than those from a s t a t i c or d e c l i n i n g one. Thus the l i f e e x p e c t a n — cy of the b i g h o r n rams I s t u d i e d i n Banff was 12.2 + 2.6 (S.D.) years (n=56 dead rams). Woodgerd (1964) however, found a l i f e expectancy of 6.7 + 2.4 years (n=17) f o r rams from Wildhorse I s l a n d , Montana. T h i s somewhat l i m i t e d data came from an i n t r o d u c e d b i g h o r n p o p u l a t i o n which had j u s t s t a b i l i z e d i t s s i z e . I t was s t i l l of h i g h q u a l i t y , as was i n d i c a t e d by the 154 h i g h r e p r o d u c t i v e success and the e a r l y maturation age of males and females. I t appears t o he no c o i n c i d e n c e , t h a t i r r e s p e c t i v e o f p o p u l a t i o n q u a l i t y , the most i n t e n s e i n t e r a c t i o n s are shown hy rams at the C l a s s I I I stage, when they are 6-7 years o f age ( F i g . 103 & 106). T h i s i s the age when most of Woodgerd's rams d i e d , and a f t e r which the m o r t a l i t y of rams g e n e r a l l y i n c r e a s e s (see Murie 1944). In the expanding p o p u l a t i o n we can t h e r e f o r e expect severe c o m p e t i t i o n among rams. The l a r g e s t , most vi g o r o u s rams would he expected t o do the b r e e d i n g . T h e i r i n d i v i d u a l s h o r t l i f e expectancy would be i r r e l e v a n t t o the e v o l u t i o n of l a r g e r horns, s i n c e these rams would be a n n u a l l y r e p l a c e d by s i m i l a r l a r g e but young rams. When the h a b i t a t becomes f i l l e d and co m p e t i t i o n reduces f o r a g e q u a l i t y and q u a n t i t y , the p o p u l a t i o n begins t o change. Reproduction d e c l i n e s , j u v e n i l e m o r t a l i t y i n c r e a s e s , sheep are l a t e r i n r e a c h i n g sexual m a t u r i t y , the average s i z e of the a d u l t d e c l i n e s , s o c i a l i n t e r a c t i o n s between rams become l e s s v i g o r o u s and t h e i r l i f e expectancy i n c r e a s e s . In such a p o p u l a t i o n vigorous l a r g e rams become uncommon and though they can be expected to be s u c c e s s f u l d u r i n g any one r u t they p a r t i c i p a t e i n , somewhat l e s s v i g o r o u s rams of s m a l l e r horn s i z e can be expected t o do more br e e d i n g due to l o n g e r l i f e expectancy. In the s t a t i c p o p u l a t i o n , s e l e c t i o n f o r l a r g e horns w i l l hence be slowed down. 155 T h i s may e x p l a i n the e x i s t e n c e o f such c l i n e s as the ammon s e r i e s ( F i g . 9 8 ) . S e l e c t i o n f o r l a r g e horns takes p l a c e i n t e n s e l y i n the c o l o n i z i n g , outer f r i n g e o f a sheep p o p u l a t i o n . Regions c l o s e to the a n c e s t r a l popula t i o n are f i l l e d q u i c k l y . Hence s e l e c t i o n f o r l a r g e horns has here o n l y a s h o r t time t o a c t . The f u r t h e r sheep move, the l o n g e r does the c o l o n i z i n g f r i n g e experience i n t e n s e s e l e c t i o n pressure f o r l a r g e horns. Yet as soon as sheep f i l l the h a b i t a t , s e l e c t i o n f o r horn s i z e s t o p s . T h e r e f o r e , a horn s i z e g r a d i e n t w i l l run from the a n c e s t r a l p o p u l a t i o n ( s m a l l horns) t o the p o p u l a t i o n f u r t h e s t away ( l a r g e h o r n s ) . As soon as p o p u l a t i o n s of sheep are s t a t i c , they f r e e z e t h e i r s o c i a l a d a p t a t i o n s at whatever l e v e l they happened t o have ac h i e v e d . In r e t r o s p e c t . In t h i s paper an attempt was made to r e  c o n s t r u c t the major e v o l u t i o n a r y f e a t u r e s of a s o c i a l s p e c i e s of l a r g e mammals. I t appears t h a t sheep arose from a r u p i c a p r i d a n c e s t o r which innovated a new, e f f e c t i v e defense mechanism a g a i n s t horn blows. I t caught such blows with a horned head. How t h i s i n n o v a t i o n arose, cannot be e x p l a i n e d at p r e s e n t , however i t had f a r r e a c h i n g consequences. I t l e d t o a s e l e c t i o n f o r a heavy s k u l l , t h i c k f a c i a l s k i n and l o s s of t h i c k body s k i n . B u t t i n g became s p e c i a l i z e d and u l t i m a t e l y evolved i n t o a c l a s h . The damage done i n f i g h t i n g became reduced and l i t t l e harm c o u l d be expected i n combat. Horn s i z e i n c r e a s e d . At f i r s t t h i s was probably o n l y a response 1 5 6 to f r a c t u r e d horn co r e s , w i t h a steady s e l e c t i o n f o r t h i c k e r bases. I t was achieved by p r o l o n g i n g and i n t e n s i f y i n g the males* j u v e n i l e period, which l e d to neoteny. The males, remaining " j u v e n i l e " , ran w i t h each other i n the f a s h i o n of j u v e n i l e s . S e l e c t i o n f o r neoteny a l s o i n c r e a s e s the a g g r e s s i v e n e s s with the consequent frequent but harmless i n t e r a c t i o n s among males. T h i s i n t u r n c r e a t e s and m a i n t a i n s a f a m i l i a r , p r e d i c t a b l e s o c i a l environment f o r the animals v i a a dominance h i e r a c h y . However, graded horn s i z e s r e  s u l t e d u l t i m a t e l y i n a p r i o r i p r e d i c t a b l e dominance ranks, i n which l a r g e horns were most a d a p t i v e . Intense s e l e c t i o n f o r l a r g e horns l e d to f u r t h e r extension of the j u v e n i l e growth phase r e s u l t i n g not o n l y i n l a r g e r horns, but l o s s of manes, i n c r e a s e d sexual dimorphism, slow b e h a v i o u r a l maturation, and l e a d e r s h i p by l a r g e s t horned rams, w h i l e the females became more j u v e n i l e i n appearance and b e h a v i o u r . In t h i s p i c t u r e , s o c i a l i t y a r i s e s as a by-product of s e l e c t i o n , and appears to be an e x t e n s i o n i n t o a d u l t l i f e o f a j u v e n i l e tendency t o f o l l o w o t h e r s . The rams are s o c i a l not so much because l i v i n g i n groups i s b e i n g s e l e c t e d f o r , as t h a t t h e i r a d a p t a t i o n s a l l o w t h i s to occur, j u s t as the s o c i a l a d a p t a t i o n s of Oreamnos would prevent i t from occur r i n g . Assuming t h a t a group of mountain goat males came to g e t h e r , how would they e s t a b l i s h a dominance order? C a t t l e can l o c k horns and push; they engage f r e q u e n t l y and form f i r m dominance without s e r i o u s i n j u r y t o each o t h e r . Mountain 157 goats could only maim each ot h e r s i n c e they n e i t h e r l o c k horns n o r c l a s h hut o n l y p i e r c e each o t h e r 1 s body. With out a dominance h i e r a r c h y no p r i o r i t y c o u l d be r e l e g a t e d a t r u t t i n g time. Without a dominance h i e r a r c h y the males would not l i v e i n a f a m i l i a r , p r e d i c t a b l e s o c i a l e n v i r o n  ment. T h i s s i t u a t i o n the males attempt to a v o i d . I t i s t h i s concept which appears to e x p l a i n the f r e q u e n t i n t e r a c  t i o n s o f rams, the l o n g dominance f i g h t s of strange rams i r r e s p e c t i v e o f the r u t t i n g season, the p e r s i s t e n t p e s t e r i n g by s m a l l e r rams o f a d i s a b l e d l a r g e r companion, as w e l l as the a d u l t mountain goat male's withdrawal i n t o a s o l i t a r y l i f e o r a t b e s t a s h o r t , d i s t a n t a s s o c i a t i o n w i t h an eq u a l . I f t h i s concept i s c o r r e c t then s o c i a l behaviour becomes comparable to the e x p l o r a t o r y behaviour o f animals i n a strange h a b i t a t . I t makes the p h y s i c a l environment f a m i l i a r and p r e d i c t a b l e to the animal, while the former makes the s o c i a l environment f a m i l i a r and p r e d i c t a b l e . In both i n  stances the animal continues to a c t u n t i l f a m i l i a r i t y i s ac h i e v e d . Whereas the s o c i a l a d a p t a t i o n s o f rams allowed them to be s o c i a l , the s o c i a l a d a p t a t i o n s of mountain goat males prevented i t . Yet both of these s p e c i e s may l i v e n o t only on the same mountains, but o f t e n are found on the same sl o p e s or r e s t i n g i n the same beds. These s p e c i e s l i v e i n much the same h a b i t a t y e t they have very d i f f e r e n t s o c i a l a d a p t a t i o n s . T h i s i n d i c a t e s t h a t the h a b i t a t has l i t t l e to do w i t h s o c i a l 158 s e l e c t i o n f o r c e s , at l e a s t f o r the males of these two b o v i d s . In the c a p r i d s the males vary more from s p e c i e s to s p e c i e s than the females. Even when comparing Oreamnos w i t h American sheep, the females a ct s u r p r i s i n g l y s i m i l a r . In both s p e c i e s they run i n small or l a r g e groups, they i n t e r a c t very l i t t l e w i t h one another so t h a t l i t t l e e v i  dence e x i s t s f o r a dominance h i e r a r c h y among females. The bands are not cohesive but break up and are almost c o n t i n u o u s l y reformed, without s t r i f e . The dominance h i e r a r c h y , so conspicuous among f r e e l i v i n g rams, appears to be non e x i s t e n t f o r females but i s q u i c k l y e s t a b l i s h e d with a few b u t t s when access i s l i m i t e d t o a s a l t l i c k f o r i n s t a n c e . I t appears t o me t h a t s o c i a l a daptations cannot be r e a d i l y judged as s u p e r i o r or i n f e r i o r , not i f c a p r i d s and r u p i c a p r i d s t h r i v e i n s i m i l a r h a b i t a t s but with d i f f e r e n t s o c i a l a d a p t a t i o n s . I see change but not progress i n the l a r g e horns of sheep f o r i n s t a n c e , or t h e i r s p e c i a l i z e d f i g h t i n g b e h a v i o u r . Although l a r g e horns e t c . are an e v o l u t i o n a r y advancement, short horned forms are very much wi t h us today, i n d i c a t i n g t h a t t h e i r s o c i a l adaptations are j u s t s o l u t i o n s , no b e t t e r or worse than those of more s p e c i a l i z e d forms. These evolved d u r i n g the short p i o n e e r i n g phase f o l l o w i n g g l a c i a t i o n , because i t was h i g h l y advantageous to be l a r g e and a f i g h t i n g s p e c i a l i s t . The c h a r a c t e r i s t i c 159 remained with each p o p u l a t i o n s i n c e they c o n t r i b u t e towards r e a c h i n g h i g h dominance and b r e e d i n g success by rams. T h i s would appear to make a r e v e r s a l of these trends almost im p o s s i b l e . Each change towards i n c r e a s e d horn s i z e and ot h e r n e o t e n i c f e a t u r e s I see as evidence of the sheep's advance i n t o new l i v i n g space, w h i l e forms i n o l d , s t a b l e r e f u g i a remained s o c i a l l y p r i m i t i v e but s u c c e s s f u l . A few i m p l i c a t i o n s are i n o r d e r . I t appears t h a t the d i f  f e r e n c e s between the rac e s canadensis and n e l s o n i are no more than about 11,000 years o l d , s i n c e t h i s i s the time span s i n c e the g l a c i e r s o f the Wisconsin g l a c i a t i o n withdrew. Sheep would have spread i n the dry, warm A l t i t h e r m a l i n t e r  v a l f o l l o w i n g g l a c i a l r e t r e a t , which l a s t e d about 5,000 y e a r s . A d d i t i o n a l r e c e s s i o n s and advances of sheep should have taken p l a c e i n the two " l i t t l e Ice Ages" which f o l l o w e d the Wisconsin. The l a s t of these took p l a c e i n the 16th and 17th cen t u r y . These should have i n t e n s i f i e d s e l e c t i o n f o r the morp h o l o g i c a l c h a r a c t e r s d i f f e r e n t i a t i n g canadensis from n e l s o n i . I f so s h o r t a time span as 10,000 years can produce such great s i z e d i f f e r e n c e s , then the presence of l a r g e sheep from P l e i s t o c e n e d e p o s i t s , t e l l o n l y o f past h a b i t a t — f l u c t u a t i o n s d u r i n g g l a c i a l advances and r e t r e a t s . B i g sheep sh o u l d have o c c u r r e d a number of times. They have appeared i n North America and A s i a q u i t e independently f o r the a r g a l i s and bighorns d e s p i t e c o n v e r g e n t l y o b t a i n e d s i m i l a r i t i e s , are q u i t e d i f f e r e n t sheep. The s k u l l s , which taxonomists r e l y on so g r e a t l y , t e l l o n l y p a r t o f the s t o r y . A r g a l i s are 160 l i g h t boned, l o n g legged steppe sheep with l i t t l e i n c l i n a  t i o n f o r c l i m b i n g . The American sheep as a whole are sto c k y and d w e l l e r s o f sl o p e s and steep, broken t e r r a i n . They are not q u i t e as s p e c i a l i z e d as ibex, but they are t r u l y a mountain, not a steppe sheep. I t can a l s o be seen t h a t they d i f f e r c o n s i d e r a b l y i n the p o s i t i o n of the rump pa t c h . F o r the reasons o u t l i n e d , I cannot a t a l l agree w i t h Stokes and Condie (1961), that l a r g e Ovis s k u l l s from American P l e i s t o c e n e d e p o s i t s i n d i c a t e Ovis  ammon as a d i r e c t a n c e s t o r of Ovis canadensis. The l a r g e ammon forms are a t e r m i n a l branch of sheep e v o l u t i o n j u s t as much as the n o r t h e r n l a r g e canadensis. I suggest, t h a t b o t h forms are products o f the l a s t g l a c i a t i o n . In c l o s i n g , may I p o i n t out th a t the e v o l u t i o n a r y changes d e s c r i b e d f o r the c a p r i d s , have a l s o taken p l a c e i n other ruminants who invaded the g l a c i a t e d areas of the c o n t i n e n t s . Deer of the genus Cervus evolved many f e a t u r e s s i m i l a r t o O v i s . The most p r i m i t i v e s p e c i e s are a l s o found i n Southeast A s i a . Species i n the f o r m e r l y g l a c i a t e d areas have l a r g e a n t l e r s , they are s o c i a l , the rump patch i s present and l a r g e s t i n the sp e c i e s f u r t h e s t from southeast A s i a (C. c a n a d e n s i s ) . and the sexual dimorphism i s g r e a t . The s p e c i e s which swarmed over the p e r i o d i c a l l y g l a c i a t e d r e g i o n s are o f t e n c h a r a c t e r i z e d by huge, h o r n - l i k e organs, not o n l y sheep and goats, but a l s o B i s o n . Megaloceros. A l c e s and i t s predecessors, and R a n g i f e r . Large horned forms a re a ge n e r a l P l e i s t o c e n e phenomenon and Ovis i s but a s u r v i v i n g , p a r t i c u l a r ease of t h i s . 1 6 1 CONCLUSIONS Sheep appear t o he r u p i c a p r i d i n o r i g i n . They e v o l v e d from a form which i n combat began n e u t r a l i z i n g b u t t s by c a t c h  i n g them with the head. T h i s allowed s e l e c t i o n f o r : (1) Heavy, pneumated s k u l l s t o absorb concussion and sturdy horn bases to r e s i s t f r a c t u r e . (2) A t h i c k s k i n over the nas a l - a n d f r o n t a l bones t o reduce damage t o the head. (3) A concurrent r e d u c t i o n of a n c e s t r a l defense mechanisms, which i n pa r t c o n s i s t e d of a t h i c k heavy h i d e . S i n c e the new defense mechanisms n e u t r a l i z e horn blows, males can i n t e r a c t without i n j u r i n g each other s e v e r e l y . T h i s r e  duced s e l e c t i o n pressure a g a i n s t : (1) Frequent a g o n i s t i c engagements. (2) Cautious c o u r t s h i p by the male of the now harmless female. (3) Males a s s o c i a t i n g w i t h one another and l i v i n g i n groups. As a consequence, dominance h i e r a r c h i e s c o u l d a r i s e and be main t a i n e d i n male groups. S i n c e h o r n s i z e i s d i r e c t l y r e l a t e d t o dominance rank and thus t o access to r e c e p t i v e females, v i g o r o u s horn growth i s a d a p t i v e . Large horns were produced v i a prolonged, and i n t e n s i f i e d annual growth. T h i s i s p o s t u l a t e d to be due to neoteny. Neoteny produced the 162 f o l l o w i n g e f f e c t s : (1) Rams mature i n e x t e r n a l appearance and s o c i a l b e haviour 5 - 6 years a f t e r sexual m a t u r a t i o n , (2) Age dependent horn s i z e g r a d i e n t s appeared i n male bands. (3) S i n c e females mature a t 1.5 - 2.5 years of age, but the growth of rams i s extended p r o g r e s s i v e l y past s e x u a l - t o u l t i m a t e maturation, the female becomes p r o g r e s s i v e l y more j u v e n i l e i n appearance. She i s paedogenic i n t h a t she r e t a i n s not o n l y a j u v e n i l e e x t e r n a l appearance throughout l i f e , but a l s o c h a r a c t e r i s t i c a l l y j u v e n i l e b ehaviour. (4) S e x u a l l y mature rams continue two j u v e n i l e t e n d e n c i e s . (a) They f o l l o w l a r g e r sheep when on the move, and (b) they a s s o c i a t e with equals d u r i n g the normal d a i l y r o u t i n e . T h i s e x p l a i n s why 1 - rams d i s a s s o c i a t e from ewes once they exceed them i n horn-and body s i z e , 2 - rams f o l l o w the l a r g e s t horned ram d u r i n g l o n g e r movements ( s i n c e i t i s the most " a d u l t " i n appearance), 3 - rams p r e f e r other rams of equal horn s i z e i n s o c i a l i n t e r a c t i o n s . (5) The more rams prolonged the p e r i o d of growth i n response t o s e l e c t i o n f o r l a r g e r horns, the more 163 they increased elements of juvenile (aggressive) behaviour, and reduced or lost the neck ruff. Since neoteny produced horn-and body size gradients in which the adult female is almost identical in external appearance to sexually mature yearling males, no absolute female form exists for sheep. In correlation we find: (1) Rams treat a l l smaller sheep as they would females. Rams change their behaviour no so much with the sex of the companion they interact with, as with i t s dominance rank. (2) The more that juvenile rams resemble females, the more sexual behaviour patterns they receive from larger rams. Subordinate rams may perform behaviour typical of females in response to dominant rams. Since rams act towards females no differently than towards young rams (except that females are more preferred), females have means to reduce the length of interactions with rams. These mechanisms are shown by non-estrous ewes. Females can assume two behavioural states which correlate with the presence or absence of estrus. The estrous ewe acts towards the male like a sexually mature, subordinate ram; the non-estrous ewe acts like a sexually immature juvenile. In estrus, 164 the ewe a s s o c i a t e s w i t h rams, does not respond t o k i c k s and most mounts, she uses c o n t a c t and a g g r e s s i v e behaviour towards rams and u r i n a t e s r a r e l y to the rams c o u r t s h i p . The non-estrous ewe a s s o c i a t e s with equals (other ewes), w i t h  draws from k i c k s and mounts, and o f t e n u r i n a t e s t o approaching rams. These a c t i o n s reduce her . i n t e r a c t i o n s with rams. I t appears t h a t s p e c i f i c hormonal changes s w i t c h on and o f f the female's "male" behaviour. Since access to r e c e p t i v e females i s l i m i t e d ^ an impetus f o r combat e x i s t s i n male groups. Rams appear to be s t r o n g l y motivated t o l i v e i n a pre d i c t a b l e s o c i a l environment throughout the year. T h i s they c r e a t e by combat, and m a i n t a i n by d i s p l a y , minor o v e r t a g g r e s s i v e i n t e r a c t i o n s and probably through c o n t a c t b e h a v i o u r . The l a t t e r appears to be r e s p o n s i b l e f o r the e v o l u t i o n of s h o r t , p l i a b l e h a i r s on the f a c e of sheep, r a t h e r than the long, b r i t t l e ones found on the body. The m a n i f e s t a t i o n of a p r e d i c t a b l e s o c i a l environment i s the dominance h i e r a r c h y . S i n c e dominance i s d i r e c t l y r e l a t e d to horn s i z e , s i n c e l a r g e horns appear to d e l i v e r a more f o r c e f u l c l a s h , and s i n c e a horn d i s p l a y immediately f o l l o w s a c l a s h , rams can a s s o c i a t e c l a s h f o r c e with horn s i z e , and hence p r e d i c t a s t r a n g e r ' s r e l a t i v e domi nance rank from h i s horn s i z e . S i n c e horns, a c t i n g 165 as rank symbols, can m a i n t a i n a p r i o r i p r e d i c t a b i l i t y of dominance r e l a t i o n s h i p s , rams can l i v e i n an open s o c i e t y . Neoteny appears to be a product of s e l e c t i o n f o r l a r g e horns i n males. Sheep e v o l u t i o n i s l i n k e d to g l a c i a t i o n , f o r the f u r  t h e r sheep moved i n t o once g l a c i a t e d areas, the more they i n c r e a s e d i n horn s i z e , sexual dimorphism, rump patch s i z e and c l a s h s p e c i a l i z a t i o n . T h i s r e l a t i o n s h i p appears to h o l d t r u e f o r o t h e r c a p r i d s and c e r v i n e deer. I t i s suggested t h a t l a r g e horns and s p e c i a l i z e d f i g h t  i n g were s e l e c t e d f o r i n p o p u l a t i o n s c o l o n i z i n g new l i v i n g space which f o l l o w e d i n the wake of g l a c i e r s . Intense s e l e c t i o n o c c u r r e d i n the expanding, h i g h q u a l i t y p o p u l a t i o n s ; i t came to a h a l t once p o p u l a t i o n s s t a b i l i z e d and the l i f e expectancy of rams i n c r e a s e d . In such p o p u l a t i o n s the s e l e c  t i v e advantage of l a r g e horns c o u l d be counter b a l a n c e d by the l o n g e r l i f e expectancy of rams of s m a l l e r horn and body s i z e . When p o p u l a t i o n s s t a b i l i z e d they r e t a i n e d whatever s o c i a l a d a p t a t i o n s they had a c q u i r e d ; p o p u l a t i o n s which arose f u r t h e r on, changed more. T h i s c o u l d account f o r the geographic c l i n e s of A s i a t i c and American sheep. In g e n e r a l , sheep e v o l u t i o n r e v o l v e d about the p e r f e c  t i o n o f a new combat type and s e c o n d a r i l y about the i n d i r e c t r e s u l t s i t p r e c i p i t a t e d . L i v i n g s o c i a l l y i n c l o s e p r o x i m i t y of o t h e r s appears to be one such secondary r e s u l t . H a b i t a t and body care behaviour appears to evolve independently of s o c i a l b ehaviour i n sheep. 166 LITERATURE CITED Anonymous. Records of North American "big game. Boon and Crocket Club. 1964 Ed. H o l t , R i n e h a r t & Wilson, New York. Alexander, G. and E. P e t e r s o n . 1961. Neonatal m o r t a l i t y i n Lambs. Aust. Vet. J . 37 (10) : 371 - 381. A l l e e , W. C. 1951. Cooperation among animals. Schuman, New York, 256 pp. Altmann, M. 1963. N a t u r a l i s t i c s t u d i e s of maternal care i n moose and e l k . i n : Mat e r n a l Behaviour of Mammals. H. L. R h e i n g o l d ( e d i t o r ) , pp. 233 - 253. J . Wiley & Sons, New York. Anderson, J . A. and J . B. Nenderson. 1961. Himalayan t h a r i n New Zealand. N.Z. Deer S t a l k e r s A s s o c i a t i o n . S p e c i a l P u b l i c a t i o n No. 2. 36 pp. Ardrey, R. 1963. A f r i c a n Genesis. D e l l P u b l i s h i n g Co. New York. 380 pp. Backhaus, D. 1961. Beobachtungen an G i r a f f e n i n Zoo l o g i s c h e n Garten und f r e i e r Wildbahn. I n s t . Pares Nat. Congo e t Ruanda-Urundi. B r u x e l l e s . 202 pp. Banks, E. M. 1964. Some aspects of sexual behaviour i n domestic sheep, Ovis a r i e s . Behaviour 23 (3-4) : 249 - 279. B o n a t t i , E. | f 1966. North mediterranean c l i m a t e d u r i n g the l a s t Wurm g l a c i a t i o n . Nature 209 : 984 - 985. Brandborg, S. M. 1955. L i f e h i s t o r y and management of the mountain goat i n Idaho. Idaho. 142 pp. Brehm, A. 1916. Brehm's T i e r l e b e n . S a u g e t i e r e 4. Buechner, H. K. 1961. T e r r i t o r i a l b ehaviour i n Uganda kob. Sci e n c e 133 : 698 - 699. C h e r n i a v s k i , F. B. 1962. On the r e p r o d u c t i o n and growth of the snow sheep (O v i s n i v i c o l a ) . Z o o l o . Zhur. XLI (10) : 1556 - 1566 ( T r a n s l a t i o n , Canad. W i l d l . S e r v i c e , Ottawa). C l a r k , J . L. 1964. The g r e a t a r c of the w i l d sheep. Univ. Oklahoma Pr e s s , Norman. 247 pp. 167 Cowan, I . McT. 1940. D i s t r i b u t i o n and v a r i a t i o n i n the n a t i v e sheep of North America. Am. M i d i . N a t u r a l i s t 24 (3) : 505 - 580. , A. J . Wood and W. D. K i t t s , 1957. Feed requirements of deer, heaver, hear and mink f o r growth and maintenance. Trans. N. Am. W i l d l . Conf. 22 : 179 - 188. and C. J . Guiguet. 1965. The Mammals of B r i t i s h Columbia (3 Ed.) Handbook No. 11 V i c t o r i a , B.C. 414 pp. Des Meules, P. 1964. The i n f l u e n c e of snow on the behaviour o f moose. (Mimeographed e x c e r p t from M. Sc. t h e s i s , O n t a r i o A g r i c . C o l l e g e , Guelph) E i s e n b e r g , J. F. 1966. The s o c i a l o r g a n i z a t i o n s of mammals. Kukenthai-Krumbach Handbuch der Z o o l o g i e . V o l . 8, 10 (7) : 1 - 92. G e i s t , V. 1963. On the behaviour of the North American Moose ( A l c e s a l c e s a n dersoni, Peterson 1950) i n B r i t i s h Columbia^ Behaviour 20 (3-4) : 377 - 416. • 1964. On the r u t t i n g behaviour of the mountain goat. J . Mammal. 45 (4) : 551 - 568. . 1966.(a) V a l i d i t y o f horn segment counts i n aging b i g h o r n sheep. J . W i l d l . Mgmt. 30 (3) : 634 - 635. . 1966.(b) E t h o l o g i c a l o b s e r v a t i o n s on some North American C e r v i d s . Z o o l . B e i t r a g e 12 : 220 - 250. . 1966.(c) The e v o l u t i o n of h o r n - l i k e organs. Behaviour ( i n p r e s s ) . . The e v o l u t i o n a r y s i g n i f i c a n c e of mountain sheep horns. E v o l u t i o n ( i n p r e s s ) . . On f i g h t i n g i n j u r i e s and dermal s h i e l d s i n mountain goat. J . W i l d l . Mgmt. ( i n p r e s s ) . Geptner, W. G., A. A. Nasimovitch and A. G. Bannikov. 1961. The mammals of the S o v i e t Union. High School p r e s s . Moskow. ( i n R u s s i a n ) . Gundlach, H. 1961. Beobachtungen b e i Versuchen zur Wildschadenverhutung am R o t w i l d des Georg von Opel- F r e i g e h e g e s . G» v. Opel Freigehege,"Krohberg Jahrbuch 1960/61 :.116 - 128.» 168 Gunn, R. G. and J . P. Robinson. 1963. Lamb m o r t a l i t y i n S c o t t i s h H i l l f l o c k s . Anim. Prod. 5 ( 1 ) : 67 - 76. Haas, G. 1958. Untersuchungen uber angeborene Vernaltensweisen ~ b e i Mahnenspringern (Ammotragus l e r v i a P a l l a s ) Z. T i e r p s y c h . 16 (2) : 218 - 242. Hansen, G. S. 1965. Growth and development of d e s e r t b i g h o r n sheep. J . W i l d l . Mgmt. 29 (2) : 387 - 391. Heusser, C. J . 1965. A P l e i s t o c e n e phytogeographic s k e t c h of the P a c i f i c North West and A l a s k a , i n : The Quaternary of North American. Wright, H. E, and Prey, D. G. (Ed.) P r i n c e t o n Univ. P r e s s , pp. 469 - 484. Katz, J . 1949. B e h a v i o u r a l i n t e r a c t i o n s i n a herd of barbary sheep. Z o o l o g i c a 34 (1) : 9 - 18. K l e i n , D. R. 1964 Range - r e l a t e d d i f f e r e n c e s i n growth of deer r e f l e c t e d i n s k e l e t a l r a t i o s . J . Mammal. 45 (2) : 226 - 235. . 1965. Ecology of deer range i n A l a s k a . E c o l . Monog. 35 : 259 - 284. Krumbiegel, I . 1954. B i o l o g i e der S a u g e t i e r e . V o l . I . Agis V e r l a g , K r e f e l d . 355 pp. Kuhme, VJ. 1965. F r e i l a n d s t u d i e n zur S o c i o l o g i e des Hyanenhundes (Lycaon p i c t u s l u p i n u s . Thomas 1902). Z. T i e r p s y c h . 22 (5) : 495 - 541. Lindsay, D. R. 1965. The importance of o l f a c t o r y s t i m u l i i n the mating behaviour of the ram. Anim. Behav.. 13 (1) : 75 - 78. Lydekker, R. 1898. W i l d oxen, sheep and goats of a l l l a n d s . Rowland Ward L t d . London. 318 pp. . 1913. Catalogue of the Ungulate mammals. V o l . I . A r t i o d a c t y l a . B r i t i s h Museum, London. 249 pp. Moser, C. A. 1962. The b i g h o r n sheep of Colorado. Dept. of Game and P i s h . Colorado. 48 pp. Munroe, J . 1962. A study of the m i l k y i e l d of three s t r a i n s of S c o t t i s h b l a c k f a c e ewes i n two environments. Anim. Prod. 4 (2) : 203 - 213. Murie, A. 1944. The wolves o f Mount McKinley. Fauna S e r i e s No. 5 U.S. N a t i o n a l Parks. Washington, D.B. 238 pp. 169 Ogren H. A. 1965. Barbary sheep. New Mexico Dept. of Game and F i s h . Santa Fe. 117 pp. Pet z s c h , H. 1957. (a) R e f l e x i o n e n zur Phylogenie der Capridae im allgemeinen und der Hausziegen im besonderen. W i s s e n s c h a f t l Zs. M. Luthe r U n i v e r s i t a t . H a l l e - Wittenberg VI (6) : 995 - 1019. . (b) Lebender o_ - B a s t a r d aus Ammatragus l e v i a P a l l . - cf x Capra h i r c u s L. - o im Berg - Zoo H a l l e - S. geboren. Z o o l . A n z e i g e r 159 (11/12) : 285 - 290. Pu r s e r , A. F. and G. B. Young. 1959. Lamb s u r v i v a l i n two h i l l f l o c k s . Anim. Prod. 1 (1) : 85 - 91. Rammell, C. G. and G. Caughley. 1964. Composition o f t h a r ' s m i l k . N.Z.J. S c i . 7 (4) : 667 - 670. Romer, A. S. 1962. The v e r t e b r a t e body. W. B. Saunders, P h i l a . 627 pp. Ryder, M. L. 1960. A study of the coat o f the mouflon Ovis  musimon w i t h s p e c i a l r e f e r e n c e to seasonal changes. P r o c . Z o o l , Soc. London 135 (3) : 387 - 408. S c h a l l e r , G. B. 1963. The Mountain G o r i l l a . Univ. of Chicago. 431 pp. S c h i n k e l , P. G. and F. B. Sh o r t . 1961. The i n f l u e n c e o f n u t r i t i o n a l l e v e l d u r i n g p r e - n a t a l and e a r l y p o s t - n a t a l l i f e of a d u l t f l e e c e and body c h a r a c t e r i s t i c s . A u s t . J . A g r i c . Res. 12 (1) : 176 - 202. S c h l o e t h , R. 1961. Das S o c i a l l e b e n des Camargue - Rindes. Z. T i e r p s y c h . 18 (5) : 574 - 627. Schmitt, J . H 1963. Ammotragus l e r v i a P a l l a s . Mahnenschaf oder Mahenenziege? Zs. S&ugetierkunde 28 (1) : 7 - 12. S l e n , S. B., R. D. C l a r k and R. Hironaka. 1963. A compari son of m i l k p r o d u c t i o n and i t s r e l a t i o n to lamb growth i n f i v e breeds of sheep. Can. J . Anim. S c i . 43 : 16 - 21. Stokes, W. L. and K. C. Condie. 1961. P l e i s t o c e n e b i g h o r n sheep from the Great B a s i n . J . P a l e o n t o l o g y 35 (3) : 598 - 609. Thenius, E. and H. Hofer. 1960. Staramesgeschichte der S a u g e t i e r e . S p r i n g e r V e r l a g . B e r l i n . 322 pp. Ulmer, F. 1941. On the weights o f D a l l sheep. J . Mammal. 22 (4) : 448 - 449. 170 Wallace, R. L. 1948. The growth of lambs b e f o r e and a f t e r b i r t h i n r e l a t i o n to the l e v e l o f n u t r i t i o n . J . A g r i c . S c i . 38 : 93;- 153, 243 - 302, 367 - 401. Walther, F. 1958. Zum Kampf und Paarungsvernalten e i n i g e r A n t i l o p e n . Z. T i e r p s y c h . 15 : 340 - 380. . 1960. Beobachtungen zum S o z i a l v e r b a l t e n der S a s i n ( H i r s c h z i e g e n a n t i l o p e A n t i l o p e c e r v i c a p r a L.) G. v. Opel Freigehege, Kronberg Jahrbuch 1959/60 : 64 - 78. • 1961. Enige Vernaltensbeobachtungen am B e r g w i l d des Georg von Opel-Freigeheges. G. v. Opel Freigehege, Kronberg Jahrbuch 1960/61 : 53 - 89.. . 1964. E i n i g e Vernalteribeobachtungen an Thomson g a z e l l e n ( G a z e l l a thomsoni Gunther, 1884) im Ngorogoro-Krater. Z. T i e r p s y c h . 21 (4) : 871 - 890. Watson, R. H., C. S. Snapsford, and J . McCance. 1956, The development o f t e s t i s , e pididymis and pe n i s i n the young Merino ram. Aust. J . A g r i c . Res. 7 : 574 - 590. Welles, R. E. and F. B. W e l l e s . 1961. The b i g h o r n of Death V a l l e y . Fauna S e r i e s No. 6. U.S. N a t i o n a l Park S e r v i c e . Washington, D.C. 197 pp. Wood, A. J . , I . McT. Cowan, and H. C. Nordan. 1962. P e r i o d i  c i t y of growth i n ungulates as shown hy deer of the genus Odocoil e u s . Can. J . Z o o l . 40 : 593 - 603. Woodgerd, W. 1964. P o p u l a t i o n dynamics of bi g h o r n sheep on Wildhorse I s l a n d . J . W i l d l . Mgmt. 28 (2) : 381 - 391. Zannier-Tanner, E. 1965. Vergle i c h e n d e Vernaltensuntersuchungen uber Hinlegen und Aufstehen b e i H u f t i e r e n . Z. T i e r p s y c h . 22 (6) : 696 - 723. 2edwitz, ( |Graf. F. X. 1937. Die Gemse. Monog. der W i l d s a u g e t i e r e , Schops. L e i p z i g . 80 pp. FIGURE 1. A 14 year o l d Stone's ram, D-ram, from the S p a t i s i study a r e a . Oct. 1962. 172 FIGURE 2. A D a l l ' s ram, 8 years o l d or o l d e r , from Kluane Lake, Yukon. Note the p r e o r b i t a l gland, the dark markings about the eye and gland, and the t h i n , wide spreading horn with d i s t i n c t horn segments. Nov. 1965. FIGURE 3. An o l d b i g h o r n ram, 12 - 15 years o l d , from the P a l l i s e r Range, Banff N a t i o n a l Park. Note the heavy horns and t h e i r broken (broomed) ends so c h a r a c t e r i s t i c of t h i s s p e c i e s . A p r i l , 1965. 173 FIGURE 4. V a r i a t i o n s i n the coat p a t t e r n i n g and horn form of Stone's rams. Note the l i g h t e r f a c e and neck c o l o u r a t i o n , the white muzzle on the dark ram, the b e l l y band on the lower ram and v a r i a t i o n s i n the shape of the rump p a t c h . I n d i v i d u a l d i f f e r e n c e s i n these c h a r a c t e r i s t i c s p e r m i t t e d i d e n t i f i c a t i o n of i n d i v i d u a l s . 174 FIGURE 5, A s i x months o l d bigh o r n lamb ( ) showing f a i r t o good development. I t i s i n i t s dark a d u l t - l i k e w i n t e r c o a t and has c l e a r l y v i s i b l e h orns. Late October, 1964. FIGURE 6 A s i x months o l d D a l l ' s lamb ( cf ) t i n October 1965. U n l i k e the b i g h o r n lamb of equal age, i t has almost no v i s i b l e h o r ns. 175 FIGURE 7. Sex-age c l a s s e s of b i g h o r n sheep arranged from a - h i n order of resemblence. (a) Lamb ( L.) - s m a l l e s t i n horn and body s i z e w i t h s h o r t j u v e n i l e f a c e . Y e a r l i n g female ( ) (12-24 months of age) next l a r g e s t i n horn and body s i z e to lamb; s t i l l r e t a i n s a s h o r t j u v e n i l e f a c e . (c) A d u l t female ( ) (2-24 years of age) Exceeded i n horn and body s i z e o n l y by equal aged males. T h i s c l a s s forms the standard others are compared by. (Note the t u f t s of broken h a i r stuck i n the f i e l d s of newly growing ones). (d) Y e a r l i n g ram ( ) (12-24 months of age) , i s very s i m i l a r i n horn-and body s i z e as w e l l as coat p a t t e r n i n g t o a d u l t ewes. The horns however, te n d to d i v e rge s l i g h t l y more i n the y e a r l i n g rams, and are t h i c k e r at the base. (e) C l a s s I ram (I) (2-3 years o l d ) . These rams surpass a d u l t ewes and y e a r l i n g rams i n horn-and body s i z e . The horns form l e s s than l / 2 c i r c l e . ( f ) C l a s s I I ram (4-6 years o l d ) . The horns form about l / 2 c i r c l e and are much l a r g e r than those of the p r e c e d i n g c l a s s . T h i s c l a s s tends t o be more massive i n body than C l a s s I . (g) C l a s s I I I ram (6-8 years o l d ) . Horns form about 3/4 of a c i r c l e and are q u i t e massive. The f a c i a l f e a t u r e s are those of o l d e r rams. The horn t i p s t e n d to be i n t a c t . (h) C l a s s IV ram (7-17 years of age)• Horn growth and body development reach a maximum. The horns form a complete c i r c l e ; these rams are a l s o termed f u l l c u r l s . No n o t i c e a b l e d i f f e r e n c e i n body s i z e e x i s t s between these and C l a s s I I I rams. FIGURE 8. A group of a d u l t b i g h o r n sheep, t h r e e ewes and two y e a r l i n g rams. The great s i m i l a r i t y between these two c l a s s e s i s apparent. The lower pawing sheep i s a ram and so i s the one behind h i s r e a r . Note the ram's white b e l l y ; i t t u r n s dark w i t h age. December 1964 FIGURE 9. A w e l l developed y e a r l i n g D a l l ' s ram. The wide spr e a d i n g horns d i s t i n g u i s h i t as a male. October 1965. 177 FIGURE 10. Two b i g h o r n ewes and a C l a s s I ram (2-1/2 years o l d , October 1964). The ram i s t y p i c a l l y l a r g e r and darker than the ewes and has a d i s t i n c t , white muzzle. T h i s ram c l a s s i s o f t e n found i n ewe bands. 178 FIGURE 11. A mule deer buck i n a r e s t i n g p o s i t i o n o f t e n used by deer but not sheep. The buck l i e s f u l l on h i s s i d e , l e g s extended sideways. Sheep support themselves on h i p and elbows. FIGURE 12. A r e s t i n g C l a s s I I I b i g h o r n i n the normal r e s t i n g p o s i t i o n . The ram i s d o z i n g and i t s eyes are p a r t i a l l y c l o s e d . 179 FIGURE 13. Sheep commonly r e s t c l o s e l y t o g e t h e r i n a group. The animals r e s t i n shallow depressions or beds which are pawed hy them. T h i s i s a hand of D a l l ' s ewes, except f o r suhadults and one 2-1/2 year o l d ram ( i n c e n t r e of p i c t u r e ) . 180 FIGURE 14. A b i g h o r n ewe and her lamb. L a t t e r t y p i c a l l y r e s t s i n c l o s e c o n t a c t u p h i l l from the ewe. The female i s i n moult. 181 FIGURE 15. Moose — u n l i k e s h e e p — t a k e advantage of the i n s u l a t i n g p r o p e r t i e s of deep, s o f t snow. T h i s h u l l has h i s extremeties w e l l b u r i e d , and only about h a l f h i s body protudes above the snow. January 1965. 182 FIGURE 16. An o l d D a l l ' s ewe c l e a n i n g a much used bed b e f o r e l y i n g down. Such beds be come covered w i t h r o c k s which have r o l l e d down the s l o p e . Note (a) how many r o c k s are i n the bed b e f o r e the ewe pawed. In (b) the ewe i s removing a l a r g e rock w i t h her f r o n t l e g . The c l e a n bed i s seen at ( c ) . 183 FIGURE 17. Pawing i s o f t e n used by sheep t o d i s l o d g e companions from a r e s t i n g p l a c e . Here i t i s done by a C l a s s IV ram on an o l d ewe. FIGURE 18. In winte r , sheep paw c r a t e r s i n the snow t o reach covered v e g e t a t i o n . Sheep wi t h i n j u r e d l e g s have r a t h e r apparent d i f f i c u l t i e s i n r e a c h i n g covered f o r a g e . T h i s i s a y e a r l i n g ram. January 1965. 184 FIGURE 19. A female b i g h o r n i n the l a t e stages of moult. Matted h a i r hangs l i k e towels from her body and w i l l e v e n t u a l  l y be l o s t as one or s e v e r a l l a r g e p a t c h e s . 185 FIGURE 20. A C l a s s I ram s c r a t c h i n g h i s withers with a horn t i p . On smal l horned sheep t h i s a c t i v i t y hares the w i t h e r s . FIGURE 21. The r e s u l t s of e x t e n s i v e horn s c r a t c h  i n g hy a ewe. Her w i t h e r s are almost bare of o l d h a i r . C i r c u l a r marks are l o c a t i o n s where t i c k s engorged. Scabs are seen on the very top of the w i t h e r s . Rubbing has broken o f f h a i r and l e f t o t h e rs s t a n d i n g i n clumps. Short, dark brown h a i r i s growing on some of the exposed a r e a . 186 FIGURE 22. A C l a s s I I Stone's ram s t r e t c h i n g i t s e l f a f t e r g e t t i n g up. The ram i s i n the sho r t summer c o a t . Note the d o r s a l s t r i p e , the shape of the rump patch compared to bi g h o r n sheep, and the head and neck c o l o u r a t i o n . 187 FIGURE 23. A u r i n a t i n g b i g h o r n ewe i n the t y p i c a l crouched p o s t u r e . The female has p a r t i a l l y shed h e r o l d c o a t . June 1964. 188 FIGURE 24. The posture o f an u n d i s t u r b e d , walking sheep. The animal i s r e l a x e d , i t s eyes are p a r t i a l l y c l o s e d and i t s head i s lowered. (The coat has been bleached so much t h a t a rump patch i s no l o n g e r v i s i b l e ) . FIGURE 25. The alarm p o s t u r e . The head i s sharp l y r a i s e d , e a r s are pinned back, eyes wide open while the h i n d l e g s are tense l y crouched. FIGURE 26. The alarm posture of e l k i s s i m i l a r t o t h at o f sheep. FIGURE 27. The a l e r t p o s t u r e . The y e a r l i n g rams have noted something i n t e r e s t i n g . Other members of the band, n o t i n g the behaviour of the rams, t u r n towards the source of i n t e r e s t . 190 FIGURE 28. A f u l l c u r l (IV) h o r n i n g the branches of a p i n e . FIGURE 29. A smal l lodge p o l e pine (Pinus c o n t o r t a ) shows the t y p i c a l e f f e c t s of fre q u e n t and l o n g h o r n i n g by sheep. Note the t h i n stem c l e a n e d of branches, the damaged bark, dead limbs and t w i s t e d t r u n k . Such damaged pines are common at t r e e l i n e . 191 FIGURE 30. O r i e n t a t i o n s of a dominant and subordinate ewe i n an encounter. Subordinate ewe ( l e f t ) l o o k s away from the dominant. 192 FIGURE 31. A comparison o f the o r i e n t a t i o n s of f o u r six-week o l d lambs i n the presence and absence o f a y e a r l i n g ewe. They t u r n e d t h e i r r e a r towards the ewe and p u l l back t h e i r ears towards the female. 1 9 3 F I G U R E 3 2 . A. t y p i c a l s o c i a l i n t e r a c t i o n o n a b e d d i n g s i t e ( a ) a n d t h e r e s u l t i n g h e d d i n g p o s i t i o n s ( h ) . A. d o m i n a n t D a l l ' s e w e d i s p l a c e s a n o t h e r e w e f r o m a b e d ; d o m i n a n t i n l o w - s t r e t c h s u b o r d i n a t e l o o k i n g a w a y . T h e d o m i n a n t 3 - l / 2 y e a r o l d r a m l o o k s o n . W h e n a t r e s t ( b ) s h e e p a r e o r i e n t e d i n s u c h a m a n n e r t h a t t h e s u b o r d i n a t e d o n o t f a c e a d o m i n a n t d i r e c t l y . T h e b e d d i n g s i t e i s t y p i c a l , a s m a l l e l e v a t e d p l a t  f o r m o f f e r i n g g o o d v i s i b i l i t y a l l a r o u n d . 194 FIGURE 33. The l o w - s t r e t c h ( C l a s s IV) and the horn t h r e a t ( C l a s s I I ) . Both rams a c t t y p i c a l l y f o r t h e i r dominance rank. FIGURE 34. The present, a horn d i s p l a y from the e l e v a t e d head. The rams have j u s t c l a s h e d and f r o z e i n t o a p r e s e n t . Note the s t i f f , tense s t a n c e . The subordinate ram (lower) has c l o s e d h i s eyes, hence does not l o o k d i r e c t l y at the dominant. FIGURE 35. The p o s i t i o n i n g of horns and body d u r i n g a h o r n - d i s p l a y . 196 FIGURE 36. A. horn d i s p l a y from the low s t r e t c h shown hy a C l a s s IV ram towards a threat-jumping C l a s s I I ram. The f u l l c u r l d i s p l a y s h i s l e f t horn most f a v o u r a b l y . Both rams act t y p i c a l l y f o r t h e i r r e s p e c t i v e ranks, the l a r g e r d i s p l a y s , the s m a l l e r t h r e a t e n s . FIGURE 37. Mutual horn d i s p l a y i n g i s performed by rams of equal horn s i z e . Two C l a s s I I rams d i s p l a y to one another. The small two year o l d ram i n foreground i s too small to enter i n a d i s p l a y . H i s sharp l y r e c l i n e d ears are a prelude t o a horn t h r e a t , the behaviour one would expect from so small a ram. FIGURE 38. A crouched l o w - s t r e t c h i s o c c a s i o n a l l y shown to females. T h i s posture form i s not common. FIGURE 39. A l o w - s t r e t c h to a young female hy a D a l l ' s ram. The s l i g h t crouch and t i p p e d up nose are more commonly assumed by D a l l ' s than b i g h o r n sheep. The t w i s t and t o n g u e - f l i c k e r are shown here by a c o u r t i n g D a l l ' s ram. The ram suddenly p u l l s forward, t w i s t s and then r e t u r n s t o a normal p o s t u r e . He t w i s t s a t e r n a t i v e l y l e f t and r i g h t . T h i s type of c o u r t s h i p i s commonly done hy young rams towards ewes approaching e s t r u s . 199 FIGURE 41. The f r o n t - k i c k performed hy a dominant on a subordinate ram. During a k i c k , the dominant may d i g i n h i s muzzle i n t o h i s opponents s i d e . FIGURE 42 The f r o n t - k i c k may l a n d anywhere on the body. I t lands however, onl y e x c e p t i o n  a l l y on the c h i n . 200 FIGURE 43. The neck f i g h t i s a v e s t e g i a l behaviour p a t t e r n of sheep, though i t i s common i n p r i m i t i v e c a p r i d s . In sheep i t pro ceeds a p p a r e n t l y no f u r t h e r than the p l a c i n g o f head and neck over the op ponents s h o u l d e r . T h i s i s a r a r e behaviour p a t t e r n . FIGURE 44 The mount i s t y p i c a l l y performed by the l a r g e r on the s m a l l e r . Note t h a t the s m a l l e r performs l o r d o s i s . 201 FIGURE 45. E j a c u l a t i o n ( a u t e r o t i c ) , l e f t by a b i g h o r n - r i g h t by a Stone's ram (from photo, a 16 mm. f i l m ) . 202 FIGURE 46. Rams i n i t i a t e c o u r t s h i p s i n l o w - s t r e t c h . Here are two c o u r t i n g the same ewe w i t h  out any d i s p l a y of h o s t i l i t y . H o s t i l e i n t e r a c t i o n s take p l a c e about the es t r o u s ewe. Both rams attempt t o i n v e s t i g a t e the v u l v a . FIGURE 47. Ewes ten d t o u r i n a t e i n response to c o u r t i n g rams. 203 FIGURE 48. A f t e r a ewe u r i n a t e s , rams l i c k and n u z z l e the u r i n and performs a L i p c u r l . Here two C l a s s IV rams l i p c u r l over the u r i n of one ewe. There i s no h o s t i l i t y ; any ram may come and l i p c u r l over a females u r i n . FIGURE 49. A ram t w i s t i n g t o a non-estrous ewe. None of the other rams pay any a t t e n t i o n . Non-estrous ewes are not defended. 2 0 4 FIGURE 50. Rubbing (a) and h o r n i n g (b) are the most common s o c i a l behaviour p a t t e r n s which small rams perform on l a r g e r ones. The s u b o r d i n a t e q u i c k l y changes from one to other behaviour. 2 0 5 FIGURE 51. A C l a s s IV ram b u t t s a C l a s s I I I ram. T h i s p a t t e r n i s used almost e q u a l l y f r e q u e n t l y by dominant on subordinate rams as v i c e - v e r s a . FIGURE 52. The rus h or horncharge i s commonly used by l a r g e rams i n c h a s i n g s m a l l e r ones away. , Ewes use i t more commonly than rams. 206 FIGURE 53. (a) The c l a s h , p r e p a r a t o r y phase i n i t i a t e d from the normal s t a n c e . The h i n d l e g s are cocked, the hack i s arched, the head s l a n t e d sideways, and the eyes t u r n e d towards the opponent. (h) Two 11 months o l d lambs i n i t i a t e the c l a s h from a more extreme b i p e d a l s t a n c e . A l l sex-age c l a s s e s of sheep c l a s h s i m i l a r l y . 207 FIGURE 54. The c l a s h , contact i s made with the opponent. Both rams c l o s e t h e i r eyes. The horns of the combatans are o f t e n c r o s s e d , though not i n t h i s i n s t a n c e . The horns have been thrown forward. 208 FIGURE 55. Rams i n s u c c e s s i v e phases of a c l a s h . From 16 mm f i l m , 24 frames/second. Numbers i n  d i c a t e frame number ( i . e . , 8 i s the e i g h t h frame or 0.3 seconds removed from frame one). A, c l a s h from the b i p e d a l s t a n c e . Note (a) the downward blow of the horns, (b) the f a l l of the body, (c) the p r o j e c t i o n of the l e f t horn, (d) the r o t a t i o n s of the s k u l l a f t e r c o n t a c t which a l l o w s the second horn to make c o n t a c t . B, note i n a d d i t i o n , the p r o p u l s i o n of the ram and h i s manner of c a t c h i n g h i m s e l f . C, the ram r o t a t e s while c l a s h i n g , thus he almost r e v e r s e s h i s p o s i t i o n from f r a m e l -28 by almost 180°. Note the f o u r components of the c l a s h f o r c e , ( l ) p r o p u l s i o n forward of the body, (2) f a l l o f the body due to g r a v i t y , ( 3 ) , blow with the head a c h i e v e d by r a p i d l y l o w e r i n g the neck, (4) the blow with the horns achieved by throwing these forward. 209 FIGURE 56. A f t e r c o n t a c t i s made, the downward push with the head c o n t i n u e s . In t h i s c l a s h , the ewe on the r i g h t p i v o t s her body about the r i g h t s h o u l d e r . Neck and body are h e l d r i g i d by the ewe and she r i s e s i n the r e a r and one the l e f t s i d e of the body. FIGURE 57. T h i s i s a second method of c o n t i n u i n g the downward blow with the head. The female on the r i g h t p i v o t s her body about the acetabulum, c o l l a p s e s the f r o n t l e g s and crouches i n the r e a r . She adds the f o r c e of her descending body t o the c l a s h . 210 FIGURE 58. A c l a s h t h a t missed. The smal l opponent jumped a s i d e . T h i s photo shows how the ram caught h i s f a l l and i t i l l u s t r a t e s t h a t the c l a s h i s a downward blow wi t h the horns. The C l a s s I I ram i n foreground has thrown h i s horns forward as i f t o c a t c h the c l a s h . 211 FIGURE 59. The c l a s h i s v a r i a b l e . The f r o n t l e g s or h i n d l e g s must be o f f the ground. The IV ram has the f r o n t l e g s o f f the ground at c o n t a c t . FIGURE 60. The horns of the opponents s l i p p e d . The ram on the r i g h t i s shown one s p l i t second b e f o r e h i s head crashes i n t o the ground. He has l o s t f o o t i n g with both f r o n t l e g s . FIGURE 61. (a) The e f f e c t of the c l a s h . The ram on l e f t i s " t e l e s c o p e d " hy the f o r c e of the c l a s h . (h) A. l a r g e C l a s s IV ram i s f o r c e  f u l l y e x e c u t i n g a c l a s h . Compare i t s posture with t h a t of the ram i n p a r t ( a ) . The s m a l l e r ram on the l e f t has h i s head t w i s t e d down and sideways and has heen pushed hack. 213 FIGURE 62. The e f f e c t of the c l a s h . Note the chunk of horn gouged out of the ram's r i g h t horn, the s c a r r e d nose, the broken horn t i p s , the h a i r t o r n from an opponents body and the broken h a i r c o v e r i n g the ram's horns. FIGURE 63 T h i s o l d ram has l o s t most of h i s l e f t horn, probably due to c l a s h i n g and f a u l t y growth of horn. 214 FIGURE 64. A defense a g a i n s t horn blows, i s t o c a t c h them and l e t them work h a r m l e s s l y a g a i n s t the t e n s i o n of the neck. The C l a s s I ram on r i g h t i s s t r i k i n g downward. The ewe a n t i c i p a t e s the blow w i t h lowered head and i s q u i c k l y o r i e n t i n g h e r body i n l i n e with the blow. The rams b u t t would depress the ewe's neck a g a i n s t the t e n s i o n of the neck. 215 FIGURE 65. S k i n t h i c k n e s s measurements ( i n mm) on f e r a l male domestic goats (upper), a Stone's ram ( c e n t r e ) , and a male mountain goat ( l o w e r ) . Note the t h i c k h i d e on the heads of the l a r g e horned s p e c i e s and the heavy dermal s h i e l d on the rump of the mountain goat. 216 FIGURE 66. The t h r e a t jump i s shown hy a C l a s s I rams towards a I I ram. T h i s group of ram i s p l a y i n g . An o l d , b a r r e n ewe ( l e f t ) has j o i n e d i n the race and i s now chased by a I ram. 217 FIGURE 67. The d i s t r i b u t i o n o f s o c i a l i n t e r a c t i o n s by sheep on other sheep of a l l sexes and s i z e s . A b s c i s s a , sex-age c l a s s e s of sheep. Ordinate, percent frequency of s o c i a l i n t e r a c t i o n s . IV to Lamb i d e n t i f i e s v a r i o u s sex-age c l a s s e s . N, stands f o r the number of i n t e r a c t i o n s which I observed each age c l a s s perform. Thus, I observed C l a s s IV rams i n 645 i n t e r a c t i o n s with other sheep. Almost 40$ of these i n t e r a c t i o n s were i n i t i a t e d on females ( ^ ) and only about 5$ on Lambs ( L. ). S T O N E ' S S H E E P 40 4 0 20 IV III <*Y 9 $ Y L. 218 FIGURE 68. I n t e r a c t i o n p r e f e r e n c e s of rams on other sheep. A b s c i s s a , sex-age c l a s s e s of sheep. Ordinate, p r e f e r e n c e index (see p. 66 ) or number of p a t t e r n s d e a l t out per i n t e r a c t i o n (o, open c i r c l e ) . The s o l i d c i r c l e s (•) stand f o r Stone's sheep p r e f e r e n c e index data, as the s o l i d l i n e (—) does f o r b i g h o r n s . The f i r s t heavy, v e r t i c a l b ar stands f o r the a c t i n g c l a s s e s of rams; the second bar stands f o r females. These two bars draw a t t e n t i o n t o the two c l a s s e s of sheep which a c t i n g rams p r e f e r i . e . C l a s s I I I rams p r e f e r other I I I rams and ewes. P r e f e r e n c e u s u a l l y t o the same or the next c l o s e s t ram c l a s s . In io in j i L P R E F E R E N C E I N D E X in O in u i O in j i 1 . I I 1 _ "i 1 1 1 1 1 1 to OJ *• — 10 OJ P A T T E R N S P E R I N T E R A C T I O N 219 FIGURE 69. Comparison of f r e q u e n c i e s w i t h which rams of two s p e c i e s of sheep approach s m a l l e r , equal and l a r g e r opponents i n a l o w - s t r e t c h . A b s c i s s a , horn s i z e g r a d i e n t of rams. Here o stands f o r the same c l a s s as the a c t i n g ram; -3 and +3 stand f o r rams th r e e horn s i z e c l a s s e s s m a l l e r and l a r g e r r e s p e c t i v e l y , than the a c t i n g ram. Ordinate, percent frequency w i t h which a c t i n g rams approach i n a l o w - s t r e t c h . F o r i n s t a n c e , b i g h o r n rams (o) approach rams of t h e i r own s i z e c l a s s i n 58$ of a l l i n t e r a c t i o n s i n low- s t r e t c h , but rams t h r e e c l a s s e s s m a l l e r are approached i n l o w - s t r e t c h 98$ of a l l i n t e r  a c t i o n s . L T H R B M C TH.S L T H R B M C TH.S 220 FIGURE 70. Frequency with which v a r i o u s behaviour p a t t e r n s occur as the f i r s t p a t t e r n a f t e r i the i n i t i a t i n g sheep has c l o s e d the d i s t a n c e and stands b e s i d e i t s opponent. A b s c i s s a , p a t t e r n s ranked i n the order o f frequency with which they f o l l o w a l o w - s t r e t c h i n i t i a  t i o n by l a r g e Stone's rams on s m a l l e r ones. Ordinate, frequency with which a given p a t t e r n f o l l o w e d i n 100 i n i t i a t i o n s . Graphs under A r e f e r to approaches i n which the i n i t i a t i n g sheep used a l o w - s t r e t c h ; under B, approaches i n which the i n i t i a t i n g animal d i d not use a l o w - s t r e t c h . LARGE < > SMALL r e f e r s to the s o c i a l s i t u a t i o n , i n which the l a r g e r approaches the s m a l l e r one. S o l i d (o) and open c i r c l e s (o) stand f o r Stone's sheep data; s o l i d l i n e only (- ) stands f o r b i g h o r n data; broken l i n e only ( ) r e f e r s t o Stone's and b i g h o r n data combined. Numbers r e f e r to the number of approaches each graph i s based on i . e . i n 322 approaches i n l o w - s t r e t c h ( A), Stone's rams (o & o ) which were l a r g e r than t h e i r opponents, d e l i v e r e d a f r o n t k i c k ( h) 38 times r i g h t a f t e r the l o w - s t r e t c h i n 100 approaches. IOO-I CO L U i u < O cr CL CL < 5 60A 2 0 A • S T O N E ' S 5 3 6 o B I G H O R N 5 2 1 I - 3 - 2 -I S M A L L E R I 2 LARGER 221 FIGURE 71. Frequency of behaviour p a t t e r n s as they occur w i t h i n i n t e r a c t i o n s . A b s c i s s a , p a t t e r n s ranked i n the order of frequency wi t h which they are used by l a r g e b i g h o r n rams i n t e r a c t i n g with sma l l ones i n the "normal" s i t u a t i o n (p. 6 2 ) . P a t t e r n s S. Rv. and F. are o u t s i d e the rank order (see p.63). Ordinate, p a t t e r n s per 100 i n t e r a c t i o n s ) . Upper graph, a c t i o n s of l a r g e r sheep ( c r o s s hatched) lower graph, a c t i o n s o f s m a l l e r sheep. A, i n t e r a c t i o n s i n i t i a t e d by l a r g e rams on small ones; B, i n t e r a c t i o n s i n i t i a t e d by small rams on l a r g e ones; C, i n t e r a c t i o n s between ewes. V e r t i c a l heavy b a r s , a c t i o n s of Stone's sheep; s o l i d l i n e , a c t i o n s of b i g h o r n sheep; broken l i n e , a c t i o n s of Stone's sheep y e a r l i n g females. Numbers above each graph show the number of i n t e r a c t i o n s each graph i s based on. F o r e x p l a n a t i o n of symbols L o . -F. see p. Lo.L T B H R h B M f t C S Ru.F Lo. 222 FIGURE 72. A b s c i s s a , and o r d i n a t e as w e l l as arrangement of graphs i s the same as i n F i g . 82. The frequency with which behaviour p a t t e r n s occur i n the "normal" s i t u a t i o n i s compared with t h a t from other s i t u a t i o n s . BIGHORN N O R M A L 184 HUDDLE 88 I I 175 \ STONE'S 176 B NORMAL 346 ABOUT (j) IN HEAT 6 8 i v d D E F E N D I N G O MO I ^ i i i i i n Lo. L T B H KHBMTKC S RJJ.F 223 FIGURE 73. Frequency of behaviour p a t t e r n s i n a dominance f i g h t between two C l a s s I I I Stone's rams. A b s c i s s a and o r d i n a t e same as F i g . 82, except t h a t h o r n i n g of the ground (Hg) r e p l a c e s s n i f f i n g of r e a r ( s ) . The numbers 318 and 284 stand f o r the number of f r o n t k i c k s d e a l t out by M- and G-ram r e s p e c t i v e l y . Observation p e r i o d , e i g h t hours. 1 2 0 i cn I O O z O h- 8 0 -u < CL UJ I- O O CL LU CL C O z cr LU H I-< CL 6 0 - 4 0 - 2 0 O 2 0 - 4 0 - 6 O - 2 3 4 - R A M D O M I N A N C E F I G H T 8 0 J 224 FIGURE 74. Frequency of behaviour p a t t e r n s i n i n t e r a c t i o n s of rams wi t h non-estrous ewes. S o l i d l i n e i n A. stand f o r b i g h o r n data, broken l i n e f o r Stone's sheep data; B, i s based on combined bighorn and Stone's sheep data. A, i n t e r a c t i o n s i n i t i a t e d by c l a s s I I - IV rams; B, y e a r l i n g rams i n t e r a c t i n g with ewes. 225 FIGURE 75. A comparison of f r e q u e n c i e s of behaviour p a t t e r n s i n i n t e r a c t i o n s of l a r g e , guard i n g rams wit h e s t r o u s ewes ( s o l i d l i n e ) and l a r g e , subordinate rams on s m a l l e r rams i n t h e presence of an es t r o u s ewe. The numbers 99 and 68 stand f o r the number of i n t e r a c t i o n s each s e t of graphs i s based on. Lower graph, s o l i d l i n e stands f o r the a c t i o n s of the es t r o u s ewe. P A T T E R N S P E R I O O I N T E R A C T I O N S O O O O O O O O O O j i i • • i i i i 226 FIGURE 76. Frequency o f sexual p a t t e r n s w i t h i n every 100 i n t e r a c t i o n s i n i t i a t e d hy C l a s s I V - I I rams on other sheep c l a s s e s . A b s c i s s a , sex-age c l a s s e s of sheep. A, frequency w i t h which rams s n i f f e d and n u z z l e d the r e a r of other sheep. B, frequency with which rams mounted other sheep. The more sheep resembled a ewe i n o u t s i d e appearance, the more f r e q u e n t l y they were t r e a t e d s e x u a l l y by rams. P A T T E R N S P E R I O O I N T E R A C T I O N S M O U N T S N I F F R E A R _ _ |V) ^ ON 00 cn O O O O O , i i i , i i 1 1 227 FIGURE 77. Withdrawal frequency of sheep from the mount (o & o) and from the k i c k (o & o ) . A b s c i s s a , sex-age c l a s s e s of sheep. Ordinate, percent of i n s t a n c e s i n which sheep withdrew r a t h e r than stood when mounted or k i c k e d . The non-estrous ewe i s s i m i l a r i n her r e a c t i o n s t o sub- a d u l t s ; the es t r o u s ewe resembles rams i n h e r response. % W I T H D R A W A L F R O M F R O N T - K I C K & M O U N T l\) ^ ON 00 O O O O +o H -fo -I r J \ / \ O + 0 GO — I C co 0 9 o / W FIGURE 78. Duri n g f e e d i n g , rams are u s u a l l y widely d i s p e r s e d . FIGURE 79. A group of three rams l e d hy a f u l l c u r l e n t e r another ram hand. The f u l l c u r l enters the ram hand i n l o w - s t r e t c h . FIGURE 80. Bighorn rams i n a huddle. Rams d i s p l a y and u s u a l l y horn, rub and n u z z l e each others head and horns. 230 FIGURE 81. Young rams at p l a y i n s p r i n g . The l e a d ram w h i r l e d and rose i n t o a t h r e a t jump on a s m a l l , b a r r e n p i e c e of f l a t ground. I t was a common h u d d l i n g p l a c e . FIGURE 82. Rams du r i n g exuberant p l a y . The I I ram on l e f t i s not t h r e a t jumping but f r o l i c k i n g , two f u l l c u r l s i n r e a r are about to c l a s h . The f u l l c u r l i n c e n t r e i s w h i r l i n g around. 231 FIGURE 83. Behaviour phases of rams i n a dominance f i g h t . A, i n i t i a t i o n o f i n t e r a c t i o n , i n low- s t r e t c h . B, k i c k phase i n which rams d e l i v e r k i c k s and present t o each o t h e r . C, disengagement i n l o w - s t r e t c h s i g n a l l i n g the impeding t h r e a t jump or c l a s h . D, b i p e d a l run by ram on l e f t ( t h r e a t jump). Ram on r i g h t gets ready to r e c e i v e the c l a s h . G, rams f e e d s i d e by s i d e f o r a short w h i l e before one or the other approaches i n l o w - s t r e t c h . (A) to be g i n another c y c l e . 2 3 2 FIGURE 84. Rams i n a v i c i o u s f i g h t . Ram on r i g h t h i t s sideways with h i s horns. Ram on l e f t moves sideways attempting t o keep h i s opponents f l a n k i n f r o n t o f him and to d e l i v e r a blow. FIGURE 85. Rams i n a v i c i o u s f i g h t . The two opponents push each other about with t h e i r s h o u l d e r s , neck and horns. 233 FIGURE 86. Two rams a c c i d e n t a l l y l o c k e d horns. T h i s occurs r a r e l y and opponents u s u a l l y f r e e themselves q u i c k l y . FIGURE 87 A 12 months o l d ram i n t e r a c t i n g with a y e a r l i n g ewe, which |rte r e p e a t e d l y begins t o mount. FIGURE 88. The same ram approaches the same ewe i n l o w - s t r e t c h . From t h e i r f i r s t b i r t h d a y on, y e a r l i n g rams s y s t e m a t i c a l  l y engage females u n t i l they dominate h e r . FIGURE 89. During f a l l , s hort hut v i c i o u s f i g h t s may e r r u p t between ewes and y e a r l i n g rams. Rams have gained dominance when ewes withdraw r a t h e r than a t t a c k . 236 FIGURE 90. A group of rams c h a s i n g an estrous ewe. The l a r g e s t horned ram i s hehind the ewe and prevents sub o r d i n a t e rams from p a s s i n g . FIGURE 91. During a chase, a I I I ram managed t o mount the ewe. The photo was taken a s p l i t second b e f o r e the dominant IV ram crashed i n t o him and knocked him o f f the ewe. 237 FIGURE 92. When the chase ends, the l a r g e s t horned ram p o s i t i o n s h i m s e l f between the ewe and h i s s u b o r d i n a t e s . The subor d i n a t e s u s u a l l y i n t e r a c t with each o t h e r . FIGURE 93 A C l a s s I ram got c l o s e t o the guarded ewe and i s chased o f f by the f u l l c u r l 238 FIGURE 9 4 . C o u r t s h i p by the estrous ewe. A, the ewe suddenly bounds away i n a coquet run, which t r i g g e r s the ram i n t o running a f t e r her f o r a few jumps. B, the ewe turns and w h i l e horn t h r e a t e n i n g prances back to the ram. C, she b u t t s and horns t h e rams chest, neck, f a c e or horns. D, she s l i p s under h i s c h i n and rubs her body al o n g h i s c h e s t . 239 FIGURE 95. Rams become p r o g r e s s i v e l y l e s s s o l i t a r y as w i n t e r advances. S o l i d c i r c l e s , data f o r SJtone's rams 1962; open c i r c l e s data f o r the very same rams i n January 1963. The w i n t e r o f 1961/62 was one of deep snow; i n January 1965 l i t t l e snow l a y on the ground. It-'.appears, t h a t when l i t t l e snow l a y on the ground, the rams d i s p e r s e d more and were more s o l i t a r y than when con f i n e d by deep snow. S i n c e i n March-A.pril 1962, h a r d snow d i d al l o w d i s p e r s a l , the p o i n t s f o r t h a t time and January 1963 are comparable. The broken l i n e i l l u s t r a t e s the probable t r u e s o c i a l tendencies of rams during w i n t e r . FIGURE 96. The o l d e r rams get, the more f r e q u e n t l y they are seen alone. Data f o r Stone's rams from January - May 1962. 6 0 n o 1963 \ \ < 4 0 - LU -I Z CO 2 0 - o \ \ \ 1962 \ J F M A M J J MONTHS S O N D 4 0 H CO < LU _ l o z LO o o 2CH 2 4 6 YEARS 8 IO 240 FIGURE 97. G o a t - l i k e c a p r i d s assembled i n order of resemblance. Bottom, Ammotragus male and female. Above them i s Capra c y l i n d r i c o r n i s . a young male and female. To the l e f t i s a male Capra c a u c a s i c a . Above l a t t e r are a Capra ibex male and female. ( A f t e r P e t z s h 1957). 241 FIGURE 98. Ammotragus. and the A s i a t i c ammon sheep assembled i n order of r e  semblance. 1 Ammotragus 2 Ovis ammon g e m e l i n i 3 o r i e n t a l i s 4 c y c l o c e r o s 5 s e v e r t z o v i 6 p o l i 7 k a r e l i n i 8 ammon Pl e a s e note the changes i n horn shape and s i z e , r e d u c t i o n of v e n t r a l neck r u f f , changes i n ear l e n g t h and shape. In k a r e l i n i ( 7 ) , the l a t e r a l horn edge s h i f t e d medianly. Not drawn to s i z e . 242 FIGURE 99. The movements and d i s t r i b u t i o n of sheep. On the North American c o n t i n e n t a l l names r e f e r to subspecies of sheep; on the E u r a s i a n c o n t i n e n t a l l names r e f e r to s p e c i e s ; i n North A f r i c a , Ammotragus r e f e r s t o the genus. The f i g u r e s 1-9 denote subspecies of Ovis ammon. as i n F i g . 98 except f i g u r e 9. T h i s r e f e r s t o 0. ammon d a r w i n i from Mongolia. Broken l i n e s i n d i c a t e probably m i g r a t i o n r o u t e s of a n c e s t r a l American sheep. Move ment i n A s i a would be probable b e f o r e the R i s s g l a c i a t i o n ; movement of a n c e s t r a l sheep i n North American i s probably pre- Wisconsin, d u r i n g the sangamon. Post Wisconsin d i s p e r s a l i n North American i s shown i n heavy l i n e s . 243 FIGURE 100. Two subspecies of Ovis ammon. Lower, o r i e n t a l i s male and female; upper, p o l i male and female ( a f t e r Walther 1961). P l e a s e note the shape and s i z e of the rump patches; p l e a s e compare these w i t h those of American sheep ( F i g . 101). 244 FIGURE 101. American sheep. Lower, 0. n i v i c o l a from S i b e r i a . Next to i t the white D a l l ' s sheep (0. d a l l i d a l l i ) ; t o i t s l e f t i s the Stone's sheep (0. s t o n e i ) . Above and to the r i g h t of the D a l l ' s sheep i s Nelson's bighorn (0. canadensis  n e l s o n i ) and the upper most sheep i s the n o r t h e r n b i g h o r n sheep (0. canadensis  c a n a d e n s i s ) . I t i s the h i g h e s t evolved canadensis form, while s t o n e i r e p r e s e n t s the most advanced d a l l i form. Both l i v e i n the f o r m e r l y g l a c i a t e d a r e a . Note changes i n rump patch, t a i l and horn s i z e as w e l l as the amount of white on the l e g s . 245 FIGURE 102. Frequency of b u t t s and mounts per 100 i n t e r a c t i o n s performed by males of v a r i o u s c l a s s e s on females. As the males grow o l d e r , they but t and mount females l e s s f r e q u e n t l y ; Lambs b u t t and mount most. P A T T E R N S P E R I O O I N T E R A C T I O N S r\j CJJ O O O FIGURE 103. A. Frequency o f f r o n t k i c k s per 100 i n t e r a c t i o n s performed by c o u r t i n g males on females. As rams grow o l d e r , they make g r e a t e r use of the f r o n t k i c k . B. same as A, except t h a t i t i l l u s t r a t e s the use made of the t w i s t . Rams use the t w i s t i n c r e a s i n g l y more frequent with age. Pl e a s e note t h a t b i g h o r n sheep used the t w i s t more f r e q u e n t l y than d i d Stone's sheep. 247 FIGURE 104. A. Percent frequency w i t h which rams of v a r i o u s s i z e c l a s s e s approached rams of t h e i r own s i z e c l a s s i n a l o w - s t r e t c h . Older rams approached t h e i r equals more f r e q u e n t l y i n l o w - s t r e t c h than d i d young rams. B. Frequency with which l o w - s t r e t c h e s were performed w i t h i n i n t e r a c t i o n s of equal s i z e d rams. Note t h a t b i g h o r n rams i n t e r a c t e d l e s s i n t e n s e than Stone's sheep. P A T T E R N S P E R I O O I N T E R A C T I O N S TWIST _ F R O N T - KICK W W s] O hi t± tn O ui O O O 248 FIGURE 105. Horn segment growth on a D a l l ' s ram (from Murie 1944) and a b i g h o r n ram. The D a l l ' s ram grows most horn e a r l y i n l i f e , the bigh o r n grows i t a l i t t l e l a t e r . 249 FIGURE 106. I n t e n s i t y of s o c i a l i n t e r a c t i o n s as i n d i c a t e d by the frequency of f r o n t k i c k s , i n the i n t e r a c t i o n s of equa]sLzed rams. The 6-8 year o l d I I I rams i n t e r a c t e d most v i g o r o u s l y . F R O N T - K I C K S P E R I O O I N T E R A C T I O N S _ 10 u) o o o o o o I ! I I I I I 250 TABLE I . Weights and measurements from two Stone's sheep. (p. 6) Age L i v e T o t a l Hind Shoulder Chest Y r s . Weight Length Foot T a i l E ar Height G i r t h RAM 6^ 170 l h . 58" 17^ 4 3f 40 44 EWE 16+ 135 l h . 51" 15^ 4 3§ 35 40 TABLE I I . Frequency with which members of v a r i o u s sheep c l a s s e s were seen without company, (p. 144) Bighorn sheep (Banff Park - 1964-65, a l l season) C l a s s IV I I I I I I oy 0 Average age ( i n y r s . ) 11 7 5 3 1 - 2 T o t a l no. seen 1796 985 1880 366 410 1907 No. seen s i n g l e 116 56 71 9 7 29 % seen s i n g l e 6.5 5.75 3.8 2.4 1.75 1.52 251 TABLE I I I , L e a d e r s h i p i n b i g h o r n rams (Banff Park, 1963-65) Based on 95 bands of rams (543 i n d i v i d u a l s ) observed d u r i n g major movements (p. 144) C l a s s e s o f rams IV I I I I I I Number of bands c o n t a i n i n g the f o l l o w i n g c l a s s e s ( A ) , Number of bands i n which rams of the f o l l o w i n g c l a s s e s were l e a d i n g ( B ) , % of bands i n the f o l l o w i n g c l a s s e s were l e a d i n g (A x i oo ) B Number o f rams l e d by the f o l l o w i n g c l a s s e s (C) % of rams l e d by the f o l l o w i n g c l a s s e s (_JL x i 0 0 ) Average s i z e of band f o l l o w i n g l e a d e r s of the f o l l o w i n g c l a s s e s ( £ ) TABLE IV. Frequency of a g g r e s s i v e p a t t e r n s i n the i n t e r a c t i o n s of l a r g e rams on small ones i n the "normal" s i t u a t i o n , A Comparison of Stone's and b i g h o r n sheep. ( A g r e s s i v e p a t t e r n s q u a n t i f i e d = c l a s h , b u t t , h o r n - t h r e a t and t h r e a t jump), (p. 146) 73 59 71 15 97.5 25.0 437 81 80.5 15.0 6.15 5.4 82 33 7 2 8.5 6.0 20 5 3.8 0.9 2.9 2.5 C l a s s e s Stone's sheep Bighorns ( a l l rams except y e a r l i n g s ) Number of i n t e r a c t i o n s 420 228 Number of a g g r e s s i v e p a t t e r n s 72 66 Number o f p a t t e r n s per 100 i n t e r a c t i o n s 17.1 29.0 ( t = 3.7, d i f f e r e n c e i n p r o p o r t i o n s extremely s i g n i f i c a n t P < .001) 

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