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Inter and intraspecific behaviour of Eumetopias Jubatus and Zalophus Californianus on a winter haulout… Brenton, Clayton Mearle 1977

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INTER AN D INT'BASP ECIFIC BE HA VIOUR OF EUMETOPIAS JDBATUS AND ZALOPHUS CALIFOHNIANUS ON A WINTER HAULOUT AREA by CLAYTON MEABLE BRENTON B . S c , Simon F r a s e r U n i v e r s i t y , 1974 THESIS SUBMITTED IN PARTIAL FULFILLMENT THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n THE FACULTY OF GRADUATE STUDIES DEPARTMENT OF ZOOLOGY He a c c e p t t h i s t h e s i s as c o n f o r m i n g to t h e r e q u i r e d s t a n d a r d THE UNIVERSITY OF BRITISH COLUMBIA August, 1977 ( c ) Clayton Mearle Brenton, 1977 In 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 o f 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 o f B r i t i s h C o lumbia, 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 stud 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 o f t h i s t h e s i s f o r s c h o l a r l y p u rposes may be g r a n t e d by the Head o f my Department o r by h i s r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f 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 ten pe rm i ss i on . Department o f Zoology  The U n i v e r s i t y o f B r i t i s h Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 ABSTRACT An ethogram of 37 b e h a v i o u r p a t t e r n s i s used t o d e s c r i b e i n t e r and i n t r a s p e c i f i c i n t e r a c t i o n s o f f i v e age-sex c l a s s e s o f Eumetopias j u b a t u s and two age-sex c l a s s e s of Zalophus c a l i f o r n i a n u s on a w i n t e r h a u l o u t a r e a . L a r g e r - o l d e r s e a l i o n s a r e dominant t o s m a l l e r - y o u n g e r ones, w i t h male E. j u b a t u s dominant t o female E. j u b a t u s and male Z. c a l i f o r n i a n u s . The b e h a v i o u r a l sequences which are used f o r e s t a b l i s h m e n t and maintenance of dominance, and which a r e i m p o r t a n t f o r energy c o n s e r v a t i o n on the b r e e d i n g r o o k e r y , a r e l e a r n e d on the non-breeding h a u l o u t areas-C h a l l e n g i n g and i n t e r a c t i n g w i t h dominants a f f o r d s s u b o r d i n a t e s t h e o p p o r t u n i t y t o "move up" the h i e r a r c h y r e l a t i o n s h i p and t o expand t h e i r b e h a v i o u r a l r e p e r t o i r e . O l d e r males p r e d o m i n a n t l y use non-body c o n t a c t d i s p l a y s d u r i n g i n t e r a c t i o n s . Younger males use more p h y s i c a l body c o n t a c t b e h a v i o u r than d i s p l a y b e h a v i o u r . The m a j o r i t y of extended Z. c a l i f o r n i a n u s i n t e r a c t i o n s a r e i n water a few meters deep, whereas E. j u b a t u s males g e n e r a l l y j o u s t on l a n d o r i n water l e s s than one meter deep. When Z. c a l i f o r n i a n u s males mimic E. j ubatus males d u r i n g an i n t e r a c t i o n , an i n c r e a s e i n p h y s i c a l a g g r e s s i o n i s observed f o r the 2. c a l i f o r n i a n u s p a r t n e r . A l a c k of metacommunication between t h e two s p e c i e s was observed on s e v e r a l o c c a s i o n s . As a r e s u l t o f an energy " t r a d e - o f f " , o l d e r E. j u b a t u s males occupy a s l i g h t l y l e s s e n v i r o n m e n t a l l y p r e f e r r e d a r e a than do o t h e r male c l a s s e s . Females a r e f o r c e d from the e n v i r o n m e n t a l l y p r e f e r r e d a r e a s by harassment from young E. j u b a t u s males. Zalophus c a l i f o r n i a n u s c l a s s e s a r e i n f l u e n c e d by weather t o a g r e a t e r e x t e n t t h a n a r e E. j u b a t u s c l a s s e s and do n o t h a u l out i n areas exposed t o c h i l l i n g winds. The reduced a g g r e s s i v e l e v e l of Z. c a l i f o r n i a n u s males, as opposed t o E. Ji.uba.t.ys males, a l l o w s i n d i v i d u a l s o f the former s p e c i e s t o crowd t o g e t h e r and r e t a i n body heat d u r i n g c o l d weather. Females appear t o i n d u c e t e r r i t o r i a l b e h a v i o u r i n o l d b u l l s . Pups appear t o i n d u c e t e r r i t o r i a l b e h a v i o u r i n l a c t a t i n g f e m a l e s . i v TABLE OF CONTENTS ABSTRACT. - i i LIST OF TABLES v i i LIST OF FIGURES i x INTRODUCTION. .1 MATERIALS AND METHODS DESCRIPTION OF STUDY SITE........... ..7 DESCRIPTION OF SEA LION CLASSES 7 DESCRIPTION OF BEHAVIOUR PATTERNS.............. 10 METHODS OF DATA COLLECTION .....16 PERIOD OF DATA COLLECTION..... ..17 RESULTS ...... . . 19 AREA A SITE DESCRIPTION...... 20 POPULATION STRUCTURE......................... 20 CLASS ASSOCIATIONS ......22 CLASS INTERACTIONS INTERACTION DURATION AND FREQUENCY ....24 ACTIVITY FREQUENCY 27 BEGINNING AND TERMINATION BEHAVIOUR (1) INITIATION OF INTERACTIONS .....30 (2) INTENTIONAL INITIATION AND DOMINANCE RELATIONSHIPS .30 (3) MOVE AWAY AND DOMINANCE RELATIONSHIPS 34 {4} FOLLOW. . . 38 INVESTIGATIVE BEHAVIOUR. 38 NON-BODY AND BODY CONTACT BEHAVIOUR 42 MISCELLANEOUS BEHAVIOUR (1) MOUNTING....... . 42 AREA B SITE DESCRIPTION 45 POPULATION STRUCTURE... 45 CLASS ASSOCIATIONS..... 45 CLASS INTERACTIONS INTERACTION DURATION ..46 ACTIVITY FREQUENCY .........48 BEGINNING AND TERMINATION BEHAVIOUR (1) INITIATION OF INTERACTIONS. .......... 48 (2) MOVE AHAY AND FOLLOW................. 48 INVESTIGATIVE BEHAVIOUR....... . ..... 52 NON-BODY AND BODY CONTACT BEHAVIOUR........ 52 MISCELLANEOUS BEHAVIOUR (1) MOUNTING ... 52 V AREA I SITE DESCRIPTION 55 POPULATION STRUCTURE 55 CLASS ASSOCIATIONS. .55 CLASS INTERACTIONS INTERACTION DURATION AND FREQUENCY.........57 ACTIVITY FREQUENCY 61 BEGINNING AND TERMINATION BEHAVIOUR (1) INITIATION OF INTERACTIONS ...61 (2) MOVE AWAY AND FOLLOW................. 61 INVESTIGATIVE BEHAVIOUR... .. ..65 NON-BODY AND BODY CONTACT BEHAVIOUR. ....65 MISCELLANEOUS BEHAVIOUR (1) MOUNTING... . ... ..............65 AREA H SITE DESCRIPTION 65 POPULATION STRUCTURE AND DISTRIBUTION........ 68 CLASS ASSOCIATIONS. 71 CLASS INTERACTIONS INTERACTION DURATION AND FREQUENCY......... 75 ACTIVITY FREQUENCY .....79 BEGINNING AND TERMINATION BEHAVIOUR (1) INITIATION OF INTERACTIONS .......85 (2) INTENTIONAL INTIATION AND DOMINANCE RELATIONSHIPS.............. 85 (3) MOVE AWAY AND DOMINANCE RELATIONSHIPS 89 {4) FOLLOW. . 89 INVESTIGATIVE BEHAVIOUR ....89 NON-BODY AND BODY CONTACT BEHAVIOUR ..94 MISCELLANEOUS BEHAVIOUR (1) MOUNTING. ...... 97 (2) SHIVERING 97 INTERACTION DESCRIPTIONS INTRASPECIFIC - E. JUBATUS 99 INTRASPECIFIC - Z. CALIF GR NIA N U S.......... 100 INTERSPECIFIC - E. JUBATUS AND 2. CALIFORNIANUS . 1 02 DISCUSS ION.......................................104 HIERARCHY 1 04 LEARNING. .......106 DISTRIBUTION..... 109 IMPLICATIONS OF INVESTIGATIVE BE HA V10 UR....... 114 THE CONSPICUOUS ABSENCE OF ZALOPHUS FEMALES AND PU PS...... ............115 FEMALE AND POP INFLUENCE ON SOCIAL ORDER...... 117 A COMPARATIVE LOOK AT SPECIES AGGRESSION AND THERMO REGULATORY INFLUENCE 120 SUMMARY,.... ............... ......123 ACKNOWLEDGEMENTS.................................126 BIBLIOGRAPHY. . 127 v i i LIST OF TABLES Table Page 1. Area A- Age-sex structure on haulout area. 21 2. Area A. Proportion of time spent i n t e r a c t i n g , i n t e r a c t i o n rate and average duration of an in t e r a c t i o n , plus the data for cal c u l a t i n g these rates.....................................25 3. Area A. Use of the fast advance behaviour pattern. ..,.32 4. Area A. Intentional i n t i a t i o n of interactions...33 5. Area A. Relationship of i n t e n t i o n a l l y i n t e r a c t i o n s to hierarchy.......................35 6. Area A. Use of the move away behaviour pattern.........................................36 7. Area A. Determination of hierarchy using move away. ............................37 8. Area A, Use of the follow behaviour pattern..... 40 9. Area A. Use of non-body and body contact behaviour patterns. 43 10. Area A. Number of mounts and attempted mounts..........................................Q1* 11. Area B. Proportion of time spent i n t e r a c t i n g , i n t e r a c t i o n rate and average duration of an inte r a c t i o n , plus the data for cal c u l a t i n g these rates. ....................47 12. Area B. Use of the advance and f a s t advance behaviour patterns.............................. 50 13. Area B. Use of the move away and follow behaviour patterns. 51 14. Area B. Use of non-body and body contact behaviour patterns..............................53 15. Area B. fielationship of time spent i n non-body and body contact behaviour patterns to t o t a l time spent interacting..........................54 16. .Area I. Class structure on haulout area......... 56 v i i i 17. Area I . P r o p o r t i o n o f t i m e spent i n t e r a c t i n g , i n t e r a c t i o n r a t e and average d u r a t i o n o f an i n t e r a c t i o n , p l u s the d a t a f o r c a l c u l a t i n g t h e s e r a t e s . ...59 18. Area I . Use o f the advance b e h a v i o u r p a t t e r n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4 19. Area I . Use o f i n v e s t i g a t i v e b e h a v i o u r p a t t e r n s . ........66 20. Area I . Use of non-body and body c o n t a c t b e h a v i o u r p a t t e r n s . . . . . 67 21. Area H. C l a s s s t r u c t u r e on h a u l o u t area.........69 22. Area H. P r o p o r t i o n of time s p e n t i n t e r a c t i n g , i n t e r a c t i o n r a t e and average d u r a t i o n of an i n t e r a c t i o n , p l u s t h e d a t a f o r c a l c u l a t i n g t hese r a t e s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 6 23. Area H. Use o f the advance b e h a v i o u r p a t t e r n . . . . 86 24. Area H. Use o f the f a s t advance b e h a v i o u r p a t t e r n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 7 25.,Area H. I n t e n t i o n a l i n i t i a t i o n of i n t e r a c t i o n s . . 8 8 26. Area H. Use o f t h e move away b e h a v i o u r p a t t e r n . 90 27. Area H. Use of the f o l l o w b e h a v i o u r p a t t e r n 92 28. Area H. Use of non-body and body c o n t a c t b e h a v i o u r p a t t e r n s . ......96 29. Area H. Number o f mounts and a t t e m p t e d mounts...98 i x LIST OF FIGURES F i g u r e Page 1. F o l g e r I s l a n d showing h a u l o u t a r e a s and l o c a t i o n o f b l i n d s and c a b i n . . . . . . . . . . . . . -.5 2. Area A. A s s o c i a t i o n o f c l a s s e s . . . . . . . 23 3. Area A. Mean i n t e r a c t i o n d u r a t i o n . . . . . . . . 26 4. Area A. I n t e r a c t i o n f r e q u e n c y . . . . . . . . . . . . 28 5. Area A. A c t i v i t y f r e q u e n c y . . . . . . . . . . . . . . . . . . . . . 2 9 6. Area A. Use o f t h e advance b e h a v i o u r p a t t e r n . . . 3 1 7. Area A. Dominance h i e r a r c h y as e s t a b l i s h e d by the move away b e h a v i o u r p a t t e r n . , , 39 8. Area A. Use of i n v e s t i g a t i v e b e h a v i o u r p a t t e r n s . . ,...,...,.....,....41 9. Area B. A c t i v i t y f r e q u e n c y . . . . . 49 10. Area I . A s s o c i a t i o n of c l a s s e s . . . . , ......58 11. Area I . I n t e r a c t i o n f r e q u e n c y . . . . . . . . . . . . . . . . . . 6 0 12.,Area I . Mean i n t e r a c t i o n d u r a t i o n . . . . . . . . . . . . . . 6 2 13. Area I . A c t i v i t y f r e q u e n c y . . . . . . . . . . . . . . . . 63 14. Area H. D i s t r i b u t i o n of sea l i o n s on beach a t h i g h and low t i d e l e v e l , . . . . . . . . . . . . . . . . . . . . 70 15. Area H. Frequency o f p h y s i c a l c o n t a c t . . . . . . . . . . 7 2 16. Area H. A s s o c i a t i o n of c l a s s e s . . . . . . . . . 73 17. Area H. P r o p o r t i o n o f sea l i o n s found s o l i t a r y on a warm sunny day and a c o l d windy day... ..........74 18. Area H. Mean i n t e r a c t i o n d u r a t i o n . . . . . . . . . . . . . . 7 7 19. Area H. I n t e r a c t i o n f r e q u e n c i e s of a l l c l a s s i n t e r a c t i o n s on h a u l o u t area.............78 20. Area H. I n t e r a c t i o n f r e q u e n c i e s f o r j u b a t u s - E. j u b a t u s i n t e r a c t i o n s . . . . . . . . . . . 80 21.,Area H. I n t e r a c t i o n f r e q u e n c i e s f o r E. j u b a t u s - Z. c a l i f g r n i a n u s i n t e r a c t i o n s . . . . . 8 1 Area H. I n t e r a c t i o n f r e q u e n c i e s f o r Z. c a l i f o r n i a n u s - E. j u b a t u s i n t e r a c t i o n s Area H. I n t e r a c t i o n f r e q u e n c i e s f o r Z. c a l i f o r n i an us - Z. c a l i f o r n i a n u s i n t e r a c t i o n s . Area H. A c t i v i t y f r e q u e n c y . . . . . . . . . Area H. Dominance h i e r a r c h y as e s t a b l i s h e d by i n t e n t i o n a l i n i t i a t i o n and move away b e h a v i o u r p a t t e r n s . Area H. Ose of i n v e s t i g a t i v e b e h a v i o u r p a t t e r n s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Area H. Types o f , i n v e s t i g a t i v e b e h a v i o u r p a t t e r n s used............................. 1 INTRODUCTION The l i v i n g and b r e e d i n g range of Eujgetopias j u b a t u s , t h e S t e l l e r sea l i o n , e x t e n d s from c e n t r a l C a l i f o r n i a {Bowley, 1929) a l o n g t h e N o r t h American west c o a s t and a c r o s s the A l e u t i a n I s l a n d s t o n o r t h e r n Japan ( N i s h i w a k i and N a g a s a k i , 1960). The t o t a l p o p u l a t i o n of E. j u b a t u s i s e s t i m a t e d a t over one q u a r t e r m i l l i o n (Kenyon and B i c e , 196 1) w i t h o v e r 200,000 l o c a t e d i n A l a s k a (Anon, 1975). B r e e d i n g r o o k e r i e s and n o n - b r e e d i n g h a u l o u t a r e a s are g e n e r a l l y l o c a t e d on i s l a n d s which a r e r o c k y and exposed t o t h e open ocean. Zalophus c a l i f o r n i a n u s ( l e s s o n ) , the C a l i f o r n i a sea l i o n , b r eeds from M a z a t l a n , Mexico, n o r t h t o San M i g u e l I s l a n d , C a l i f o r n i a ( P e t e r s o n and Bartholomew, 1967). During the n o n - b r e e d i n g s e a s o n , f e m a l e s and pups m i g r a t e t o s l i g h t l y s o u t h of t h i s range and have never been r e c o r d e d n o r t h o f Ano Nuevo I s l a n d , 40 m i l e s s o u t h of San F r a n c i s c o . Males f r e q u e n t the c o a s t s of Oregon, Washington, and B r i t i s h C olumbia d u r i n q w i n t e r months ( G u i g u e t , 1953; Mate, 1973; B i g g , 19 73) and are found as f a r n o r t h as s o u t h e r n Alaska ( C a l k i n s , D., per. com.) . The p o p u l a t i o n of Z. c a l i f o r n i a n u s i s e s t i m a t e d a t 50,000 (Mate, 1975). Zalophus c a l i f o r n i a n u s g e n e r a l l y h a u l out on sandy or b o u l d e r beaches of remote i s l a n d s . There has been an i n c r e a s e i n the number of Z. c a l i f o r n i a n u s s i t e d i n B r i t i s h Columbia i n t h e past t e n years ( F i s h e r , H.D., p e r . com.). The cause of t h i s i s unknown. An i n c r e a s e i n the b r e e d i n g p o p u l a t i o n has been 2 r e p o r t e d (Smith e t a l . , 1974a) and t h e c o r r e s p o n d i n g e x p a n s i o n of the w i n t e r i n g range o f f e r s an o p p o r t u n i t y t o observe what e f f e c t , i f any, t h e Z. c a l i f o r n i a n u s p o p u l a t i o n may have on t h e i n d i g e n o u s B r i t i s h Columbia E. j u b a t u s p o p u l a t i o n . At l e a s t two v i r u l e n t d i s e a s e s have been i d e n t i f i e d i n 2. c a l i f o r n i a n u s (Smith e t a l . , 1973; Smith e t a l . , 1974b). One of t h e s e i s a L e p t o s p i r a v i r u s a s s o c i a t e d w i t h premature b i r t h s (Smith e t a l . , 1974a). These d i s e a s e s c o u l d be t r a n s m i t t e d t o t e r r e s t r i a l mammals and/or E. -jubatus i n B r i t i s h Columbia ( P r a t o e t a l . , 1974). An e x a m i n a t i o n o f t h i s " p o t e n t i a l " d i s e a s e t r a n s m i s s i o n was beyond t h e scope o f t h i s s t u d y but i t was f e l t t h a t a q u a n t i t a t i v e i n t e r a c t i o n s t u d y i n v o l v i n g Z. c a l i f o r n i a n u s and E. j u b a t u s was warranted to e s t a b l i s h a base l i n e of i n f o r m a t i o n f o r p r e s e n t i n t e r and i n t r a s p e c i f i c b e h a v i o u r which c o u l d a l s o be used t o i n d i c a t e any i n t e r and i n t r a s p e c i f i c b e h a v i o u r a l changes which may r e s u l t f o r these two s p e c i e s i n t h e f u t u r e . I t was f u r t h e r d i s c o v e r e d t h a t i n t e r s p e c i f i c q u a n t i t a t i v e s t u d i e s on p i n n i p e d s p e c i e s a r e n o n - e x i s t e n t and i t i s f e l t t h a t i n o r d e r t o c o m p a r a t i v e l y a n a l y z e two o r more s p e c i e s o b j e c t i v e l y a q u a n t i t a t i v e approach must be d e v e l o p e d . Harlow (1975) has done t h e o n l y e x t e n s i v e c o m p a r a t i v e b e h a v i o u r a l s t u d y on two s e a l i o n s p e c i e s . I t does not i n v o l v e i n t e r s p e c i f i c b e h a v i o u r and i s p r i m a r i l y a d e s c r i p t i v e a c c o u n t . T h i s s t u d y was done d u r i n g the n o n - b r e e d i n g season of E. j u b a t u s and 2. c a l i f o r n i a n u s . However, a b r i e f a ccount of the r e p r o d u c t i v e b i o l o g y and t h e o r e t i c a l e n e r g e t i c s of 3 the sea l i o n ' s r e p r o d u c t i v e system i s g i v e n below, s i n c e t h e s e w i l l be r e f e r r e d t o e x t e n s i v e l y throughout t h e t h e s i s . Both E. j u b a t u s and Z. c a l i f o r n i a n u s are polygynous and s e x u a l l y d i m o r p h i c . Consequently one male may c o p u l a t e w i t h s e v e r a l f e m a l e s . I n o r d e r f o r a b u l l t o p a r t i c i p a t e i n b r e e d i n g i t must occupy and m a i n t a i n a t e r r i t o r y i n which e s t r o u s f e males a r e l o c a t e d . The male's r e p r o d u c t i v e s u c c e s s i s r e f l e c t e d i n the number of f e m a l e s t h a t he i n s e m i n a t e s . The number of f e m a l e s a male i n s e m i n a t e s i s d e t e r m i n e d p r i m a r i l y by ( i ) the number o f e s t r o u s females i n h i s t e r r i t o r y , and c o r r e s p o n d i n g l y the s i z e of t h e t e r r i t o r y , ( i i ) t h e l e n g t h of time t h a t he can m a i n t a i n t h a t t e r r i t o r y and ( i i i ) the r e l a t i v e t i m e t h a t he must spend i n maintenance o f the t e r r i t o r y , a t t e n d i n g t o t h e f e males and r e s t i n g . Any b u l l l e a v i n g a t e r r i t o r y , even t o f e e d , may f i n d t h e t e r r i t o r y o c c u p i e d by a n o t h e r b u l l when he r e t u r n s . Thus a f i g h t f o r ownership may ensue. The f a t r e s e r v e s a c q u i r e d b e f o r e e s t a b l i s h m e n t o f the t e r r i t o r y s u s t a i n the b u l l w h i l e he m a i n t a i n s h i s t e r r i t o r y . I t i s t h i s f a t r e s e r v e , or s t o r e d e n e r g y , and how i t i s p a r t i t i o n e d i n t o t h e v a r i o u s a c t i v i t i e s undertaken on t h e t e r r i t o r y t h a t w i l l l a r g e l y determine t h e b u l l ' s r e p r o d u c t i v e s u c c e s s . U n t i l r e c e n t l y p i n n i p e d b e h a v i o u r a l s t u d i e s have been r e s t r i c t e d t o f u r s e a l s ( C a l l o r i n u s u r s i n u s and A r c t g c e p h a l u s f o r e s t e r i ) because of the commercial v a l u e of t h e s e s p e c i e s (Bartholomew, 1953; Bartholomew and H o e l , 1953; P a u l i a n , 196U; P e t e r s o n , 1965, 1968; Rand, 1967). In t h e p a s t ten y e a r s , however, s e v e r a l q u a n t i t a t i v e 4 b e h a v i o u r a l s t u d i e s have been done on Z. c a l i f o r n i a n u s {Peterson and Bartholomew, 1967} and E. j u b a t u s (Sandegren, 1970; G e n t r y , 1970; H a r e s t a d , 1973; E d i e , A., per. com.). These s t u d i e s have been r e s t r i c t e d t o t h e b r e e d i n g seasons of both s p e c i e s (Hay t o J u l y ) . I n t e r s p e c i f i c b e h a v i o u r between t h e s e two s p e c i e s has never been q u a n t i f i e d and i s mentioned o n l y b r i e f l y by s e v e r a l a u t h o r s ( O r r , 1965; Pe t e r s o n and Bartholomew, 1967; Mate, 1973). T h i s s t u d y c e n t e r s on i n t e r and i n t r a s p e c i f i c b e h a v i o u r o f E. j u b a t u s and Z. c a l i f o r n i a n u s on a w i n t e r h a u l o u t i s l a n d . The s t u d y was done on F o l g e r I s l a n d , B r i t i s h Columbia (48° 49» N., 125 015» H.) ( F i g u r e 1) which i s the l a r g e s t s y m p a t r i c h a u l o u t area f o r Z. c a l i f o r n i a n u s and E. j u b a t u s i n B r i t i s h C o lumbia. A p p r o x i m a t e l y 500 Z. c a l i f o r n i a n u s and 350 E. j u b a t u s were observed d u r i n g t h e peak h a u l o u t p e r i o d of mid-December. The i s l a n d i s a p p r o x i m a t e l y 4 00 by 600 meters. I t i s d e n s e l y c o v e r e d w i t h s e v e r a l s p e c i e s of c o n i f e r o u s t r e e s and much undergrowth, p r i m a r i l y G a u l t h e r i a s h a l l o n . S e v e r a l s p e c i e s o f b i r d s n e s t on t h e i s l a n d i n c l u d i n g b a l d e a g l e s ( H a l i a e e t u s l e u c o c e p h a l u s ) , n o r t h w e s t crows (Coryus c a u r i n u s ) , f o x s p a r r o w s ( P a s s e r e l l a i l i a c a ) , g l a u c o u s winged g u l l s (Parus g l a u c e s c e n s ) , b l a c k o y s t e r c a t c h e r s (Baematopus bachmani), p e l a g i c cormorants ( P h a l a c r o c o r a x p e l a g i c u s ) and pig e o n g u i l l e m o t s (Cepphus cglumba). Mammals f r e q u e n t i n g t h e i s l a n d a r e r i v e r o t t e r s ( L u t r a c a n a d e n s i s ) , harbour s e a l s (Pboca v i t u l i n a ) , C a l i f o r n i a sea l i o n s (Z. c a l i f o r n i a n u s ) , S t e l l e r sea l i o n s (E. j u b a t u s ) and n o r t h e r n e l e p h a n t s e a l s (Mirounga Figure 1. Folger Island. A to I - Sea l i o n haulout areas. 1 to 6 - Location of b l i n d s . X - Location of cabin. £• jubatus haulout areas. *///////, Z . c a l i f orn i a n u s haulout areas. 100 METERS 6 a u g u s t i r o s t u s ) . Z a l o ^ h u s c a l i f g r n i a n u s and E. j u b a t u s h a u l out on F o l g e r I s l a n d between mid September and l a t e A p r i l w i t h g r e a t e s t numbers found i n November and December. The sea l i o n s were d i v i d e d i n t o seven a g e - s e x - s p e c i e s c l a s s e s { f i v e c l a s s e s f o r E. -jubatus; two c l a s s e s f o r Z. c a l i f o r n i a n u s ) . An ethogram of 37 b e h a v i o u r p a t t e r n s was used t o d e s c r i b e i n t e r and i n t r a s p e c i f i c b ehaviour of t h e two s p e c i e s . The i s l a n d was n a t u r a l l y d i v i d e d i n t o seven h a u l o u t a r e a s . Four areas (A, B, H and I , F i g u r e 1) had unique age-s e x - s p e c i e s s t r u c t u r e s , so c o m p a r i s o n s o f behaviour between v a r i o u s t y p e s o f p o p u l a t i o n s t r u c t u r e was p o s s i b l e . My r e s u l t s on b e h a v i o u r a l development of E. j u b a t u s a r e s i m i l a r to t h o s e found by H a r e s t a d (1973) and so I do not r e p e a t a d i s c u s s i o n of t h i s p a r t i c u l a r t o p i c . Only two of the p o t e n t i a l f i v e age-sex c l a s s e s o f Z. c a 1 i f o t n j a n u s are i n c l u d e d i n t h i s s t u d y . Thus an e v a l u a t i o n o f t h i s s p e c i e s * b e h a v i o u r a l ontogeny i s i m p r a c t i c a l . The o b j e c t of t h i s t h e s i s i s to a n a l y z e the i n t e r and i n t r a s p e c i f i c b e h a v i o u r of the age-sex c l a s s e s o f E. j u b a t u s and Z. c a l i f o r n i a n u s found on F o l g e r I s l a n d , and t o d e termine i f these f i n d i n g s can be r e l a t e d t o t h e h i e r a r c h i a l r e l a t i o n s h i p s and t h e d i s t r i b u t i o n o f sea l i o n c l a s s e s on the i s l a n d . F u r t h e r I want to d i s c u s s t h e s e b e h a v i o u r a l a t t r i b u t e s as they p e r t a i n t o the b e h a v i o u r of the two s p e c i e s t h r o u g h o u t t h e year- T h i s t h e s i s does not d e a l w i t h a s i n g l e - c e n t r a l h y p o t h e s i s , but r a t h e r p r e s e n t s a q u a n t i f i e d account o f s e v e r a l f a c e t s o f t h e b e h a v i o u r of the two sea l i o n s p e c i e s . 7 MATERIALS AND METHODS DESCRIPTION OF STUDY AREA F o l g e r I s l a n d i s exposed t o t h e open P a c i f i c Ocean. S w e l l s t o 10 meters are not uncommon on t h e so u t h - w e s t e r n s i d e d u r i n g w i n t e r storms. The m a j o r i t y o f t h e i s l a n d ' s p e r i m e t e r c o n s i s t s of s t e e p c l i f f s w i t h o n l y a narrow i n t e r t i d a l . Beach H ( F i g u r e 1) i s the o n l y l a r g e beach and d u r i n g even moderate storms i t i s c o v e r e d w i t h water to the base o f the c l i f f s . A s m a l l c a b i n and f i v e b l i n d s were c o n s t r u c t e d d u r i n g the summer o f 1974. The b l i n d s were l o c a t e d near the h a u l o u t a r e a s a t the t o p s of the c l i f f s as shown i n F i g u r e 1. In g e n e r a l , a n i m a l s observed were w i t h i n 60 meters of the b l i n d s , t h e r e f o r e b i n o c u l a r s were not n e c e s s a r y except f o r i d e n t i f y i n g i n d i v i d u a l a n i m a l s . T h i s a l l o w e d the o b s e r v e r t o Match s p e c i f i c a n i m a l s as w e l l as t h e h a u l o u t a r e a i n g e n e r a l . S e v e r a l s e a l i o n s o f each s p e c i e s were i n d i v i d u a l l y i d e n t i f i a b l e due t o unique s c a r p a t t e r n s and/or p h y s i c a l d e f o r m i t i e s . A d e s c r i p t i o n o f t h e p h y s i c a l c h a r a c t e r i s t i c s o f each s t u d y s i t e i s g i v e n a t t h e b e g i n n i n g o f each s e c t i o n of the r e s u l t s c o v e r i n g t h a t s i t e . DESCRIPTION OF SEA LION CLASSES The sea l i o n s were d i v i d e d i n t o c l a s s e s a c c o r d i n g t o age, sex and s p e c i e s . F i v e c l a s s e s were used f o r E. 8 j u b a t u s . These c l o s e l y f o l l o w t h o s e g i v e n by H a r e s t a d (1973) who based h i s c l a s s s e p a r a t i o n on growth c u r v e s found i n P i k e (1966). The c l a s s of " s m a l l cows" d e s c r i b e d by Ha r e s t a d (1973) i s not i n c l u d e d s i n c e a n i m a l s f i t t i n g h i s d e s c r i p t i o n were not observed. A l l cows appeared t o be the s i z e of tho s e f r e q u e n t i n g b r e e d i n g r o o k e r i e s . A b b r e v i a t i o n s used i n t e x t (EOB, EIB, ZIB, e t c . ) w i l l r e f e r t o t h e c l a s s e s as d e s c r i b e d below. 1. Eumetopias j u b a t u s o l d b u l l s (EOB) - Much l a r g e r t han a l l o t h e r c l a s s e s ; t o 4 m. i n l e n g t h and 1,000 kg. i n weight; l a r g e f o r e h e a d and very s t o u t neck; t h i c k l o w e r jaw; l o n g mane; t e s t e s o b v i o u s . 2. Eumetopias j u b a t u s i n t e r m e d i a t e b u l l s (E.IB) T y p i c a l l y 2/3 s i z e of o l d b u l l and 1 1/2 t o 2 t i m e s s i z e of young b u l l ; 4 to 6 years o l d ; a c c e n t u a t e d forehead and s t o u t neck; lower jaw n o t as t h i c k o r massive as t h a t o f an o l d b u l l ; n o t i c e a b l e mane; t e s t e s not as o b v i o u s as on o l d b u l l . 3. Eumetopias j u b a t u s ycung b u l l s (EYB) - One-half the s i z e of i n t e r m e d i a t e b u l l s ; 2 t o 4 y e a r s o l d ; some i n d i c a t i o n o f an a c c e n t u a t e d f o r e h e a d ; neck n o t s t o u t ; t e s t e s not r e a d i l y seen; mane s h o r t or n o n - e x i s t e n t ; l o w e r jaw . n o t t h i c k ; p e n i s v i s i b l e when an i m a l i s moving. 4. Eumetopias j u b a t u s cows (ECS) - The s i z e o f young b u l l s o r s l i g h t l y l a r g e r ; s l i m neck; s l i m lower jaw; no mane; smooth p r o f i l e . 9 5- Eumetopias j u b a t u s pups (EPS) - Much s m a l l e r than o t h e r c l a s s e s ; about 6 months o l d ; p e l a g e darker than o t h e r c l a s s e s ; g e n e r a l l y a s s o c i a t e d with a f e m a l e ; no o b v i o u s secondary sex c h a r a c t e r i s t i c s . The c l a s s e s do not form d i s t i n c t u n i t s . G r e a t e s t d i f f i c u l t y was found i n d i s t i n g u i s h i n g EYB from ECS, however i n a l l observed i n t e r a c t i o n s , secondary sex c h a r a c t e r i s t i c s were seen and t h e sex was de t e r m i n e d . The e x a c t age of s e x u a l m a t u r i t y has not been determined but i t i s b e l i e v e d ( P i k e , 1966; T h o r s t e i n s e n and L e n s i n k , 1962; P e r l o v , 1971) t h a t EOB, EIB and a l l but perhaps t h e s m a l l e s t of the ECS are s e x u a l l y mature, whereas EYB and EPS a r e n o t . Three c l a s s e s of 2. c a l i f o r n i a n u s were observed i n t h e s t u d y . 1- Zalophus c a l i f o r n i a n u s o l d b u l l s (ZOB) N o t i c e a b l y l a r g e r than o t h e r two Z. c a l i f o r n i a n u s c l a s s e s ; comparable i n s i z e t o EIB; 7 y e a r s of age and o l d e r ; v e r y s t o u t neck and muzzle; pronounced s a g g i t a l c r e s t ; o v e r a l l p e l a g e v e r y dark brown w i t h muzzle and s a g g i t a l c r e s t a r e a b l o n d or s i l v e r y ; t e s t e s o b v i o u s . 2- Zalophus c a l i f o r n i a n u s i n t e r m e d i a t e b u l l s (ZIB) -S m a l l e r than o l d b u l l s but l a r g e r than young b u l l s ; 5 t o 7 y e a r s o f age; neck much slimmer than o l d b u l l ' s ; p e l a g e medium brown t o dark brown w i t h s a g g i t a l c r e s t and muzzle u s u a l l y same c o l o u r as t h e r e s t o f t h e body; t e s t e s o b v i o u s . 3- Zalophus c a l i f o r n i a n u s young b u l l s (ZYB) - About 10 2/3 t h e s i z e o f i n t e r m e d i a t e b u l l s ; 2 t o 5 ye a r s o l d ; neck s l i m ; no s a g g i t a l c r e s t ; p e l a g e i s s i l v e r y - t a n t o l i g h t brown; t e s t e s not o b v i o u s . No female 2- , c a l i f o r n i a n u s were seen on F o l g e r I s l a n d d u r i n g t h e s t u d y and th e y have not been r e c o r d e d n o r t h of Ano Nuevo I s l a n d near San F r a n c i s c o ( P e t e r s o n and Bartholomew, 1967). The c l a s s of ZOB i s s e x u a l l y mature. I t i s assumed t h a t ZIB a r e a l s o s e x u a l l y mature, s i n c e t h i s c l a s s has c o n s p i c u o u s l y d e v e l o p e d secondary sex c h a r a c t e r i s t i c s . ZYB are not s e x u a l l y mature ( P e t e r s o n and Bartholomew, 1967). Only f o u r ZOB were seen on the i s l a n d d u r i n g the s t u d y and t h e r e f o r e q u a n t i t a t i v e d a t a f o r ZOB were not t a k e n . DESCBIPTION OF BEH AVIOUB PATTEBNS T h i r t y - s e v e n b e h a v i o u r p a t t e r n s a r e d e s c r i b e d . These i n c l u d e 33 used by H a r e s t a d (1973) and Harestad and F i s h e r (1975) p l u s 4 p a t t e r n s s p e c i f i c t o Z. c a l i f o r n i a n u s . These p a t t e r n s a r e d i v i d e d i n t o f i v e groups; B e g i n n i n g and T e r m i n a t i o n , I n v e s t i g a t i v e , Non-body C o n t a c t , Body Con t a c t and M i s c e l l a n e o u s . A l t h o u g h each of the b e h a v i o u r p a t t e r n s may not be p r e s e n t e d i n d i v i d u a l l y i n t h e r e s u l t s or d i s c u s s i o n , t h e y are g i v e n here t o f a c i l i t a t e a b e t t e r u n d e r s t a n d i n g o f p i n n i p e d b e h a v i o u r . 1 1 BEGINNING AND TERMINATION BEHAVIOUR PATTERNS These patterns are used to i n i t i a t e , prolong or end s o c i a l interactions- They are not necessarily used in a l l interactions. Behaviour patterns l i s t e d i n any one of the other behaviour categories may also be used for these three functions. 1. Advance - A sea l i o n approaches another sea l i o n with intent. The approach i s made at a slow or medium s h u f f l e . This does not appear to be an aggressive behaviour pattern. 2. Fast advance - This i s s i m i l a r to the advance except that i t occurs very quickly- It appears to be a very aggressive behaviour pattern. 3. Hove away - A sea l i o n moves away from another sea l i o n . This can occur at a slow to medium shu f f l e or at a fast run. The use of thi s behaviour pattern appears to be a response to the other s o c i a l partner's behaviour. Subordinates may use t h i s behaviour pattern when in t e r a c t i n g with dominants and females may use i t when harassed by males. 4. Follow - A sea l i o n follows or chases another sea l i o n . This can occur at a slow to medium shuffle . or at a fast run. It i s used by males i n interactions with females, as well as by dominants in interactions with subordinates. 12 INVESTIGATIVE BEHAVIOUR PATTERNS These p a t t e r n s a r e n o n - a g g r e s s i v e and appear t o be used i n i d e n t i f y i n g c e r t a i n c h a r a c t e r i s t i c s o f the user ' s s o c i a l p a r t n e r . 5. Nosing A - A sea l i o n p u t s i t s nose on or near the head, a n t e r i o r body or back of another sea l i o n . 6. Nosing B - A sea l i o n p u t s i t s nose on o r near the p e r i a n a l r e g i o n of a n o t h e r s e a l i o n . 7. Nosing C - A s e a l i o n p u t s i t s nose on or near the ground where a n o t h e r sea l i o n has r e c e n t l y passed. 8. L i c k i n g A - A sea l i o n l i c k s a n o t h e r sea l i o n on t h e head, a n t e r i o r body o r back. 9. L i c k i n g B - A sea l i o n l i c k s a n o t her s e a l i o n i n the p e r i a n a l r e g i o n . NON-BODY CONTACT BEHAVIOUR PATTERNS These p a t t e r n s a r e m a i n l y used as a g g r e s s i v e d i s p l a y s by o l d e r a n i m a l s but may f u n c t i o n i n n o n - a g g r e s s i v e communication between c e r t a i n s o c i a l p a r t n e r s . 10. Mouth - The mouth o f a sea l i o n i s opened and d i r e c t e d towards another s e a l i o n . T h i s b e h a v i o u r p a t t e r n i s g e n e r a l l y an a g g r e s s i v e d i s p l a y but may be used i n a n o n - a g g r e s s i v e c o n t e x t (e.g. mother-pup i n t e r a c t i o n s ) . 11. Snobbing - A s e a l i o n s i t s w i t h i t s head on a 45 degree a n g l e . The eyes a r e sometimes c l o s e d . T h i s i s a v e r y a g g r e s s i v e d i s p l a y and can be used i n c o m b i n a t i o n w i t h o t h e r b e h a v i o u r p a t t e r n s such as t u r n away ( 1 3 ) . 13 12. F u l l neck - A sea l i o n s i t s w i t h i t s head a t a 90 degree a n g l e . The eyes are o f t e n c l o s e d . T h i s b e h a v i o u r p a t t e r n i s an a g g r e s s i v e d i s p l a y p o s t u r e . 13. Turn away - A s e a l i o n moves s l i g h t l y back from i t s s o c i a l p a r t n e r and then t u r n s i t s head away. The rostrum i s u s u a l l y p o i n t i n g about 45 degrees h o r i z o n t a l l y away from the o t h e r sea l i o n . 14. Nodding - A sea l i o n nods i t s head, u s u a l l y s u c c e s s i v e l y . , T h i s may be a v i o l e n t or r e l a t i v e l y s l o w a c t i o n . I t i s a very a g g r e s s i v e b e h a v i o u r p a t t e r n and i s used most f r e q u e n t l y by the o l d e r males i n a g o n i s t i c i n t e r a c t i o n s . 15. Neck waving - A sea l i o n waves i t s head r a p i d l y from s i d e t o s i d e . T h i s i s u s u a l l y done d u r i n g an i n t e r a c t i o n but a l s o o c c u r s i n s o l i t a r y a n i m a l s . The head i s held h i g h and the sea l i o n i s g e n e r a l l y v o c a l i z i n g . When two a n i m a l s are i n v o l v e d t h e heads move out of phase. T h i s b e h a v i o u r p a t t e r n i s d e s c r i b e d by S t i r l i n g (1970) and appears t o a p p r o x i m a t e t h a t mentioned by P e t e r s o n and Bartholomew (1967) and P e t e r s o n (1968). BODY CONTACT BEHAVIOUR PATTERNS P h y s i c a l c o n t a c t i s a main c h a r a c t e r i s t i c of these a g g r e s s i v e b e h a v i o u r p a t t e r n s , however, c o n s t a n t c o n t a c t i s not n e c e s s a r y . 16. Crossed-mouth - The mouths of two i n t e r a c t i n g sea 14 l i o n s are open and very close together. The vibrissae are erect and directed forward. The sea l i o n s move and shake t h e i r heads while at the same time keeping t h e i r mouths opposed. Necking A - A sea l i o n uses i t s neck to stroke the neck of another sea l i o n . This i s not as aggressive as the other body contact behaviour patterns. Necking B - A sea l i o n l i g h t l y pushes another sea l i o n with i t s neck and chest. Necking C - A sea l i o n vigorously pushes another with i t s neck and chest. The sea l i o n s are usually facing each other. This i s an intense aggressive behaviour pattern with the pushing being strong enough at times to move one of the animals backwards. Necking D - A sea l i o n vigorously pushes another with i t s neck and chest while attempting to bite the f o r e f U p p e r s of the other sea l i o n . This i s an intense behaviour pattern and a more involved variation of necking C. Biting A - A sea l i o n l i g h t l y bites another. This occurs in f i g h t s between males and interactions involving males and females. Biting B - A sea l i o n vigorouly bites another. This appears quite vicious and i s used only by males. Lunging - A sea l i o n with i t s mouth open lunges at another. The jaws may snap shut. The vibrissae 15 a r e e r e c t and extended f o r w a r d . T h i s o c c u r s o n l y i n f i g h t s between males. MISCELLANEOUS 24. Down - A sea l i o n l e i s u r e l y l i e s down. I t s body does not have a s t r e t c h e d appearance. The animal does not seem a l e r t . 25. Ground - A sea l i o n l i e s down w i t h the body weight m o s t l y on t h e f o r e f U p p e r s . The neck i s extended and t o u c h i n g the ground. The body appears t o be s t r e t c h e d . The c h i n may t o u c h the ground o r be r a i s e d s l i g h t l y . The a n i m a l seems a l e r t . 26. Moving - A sea l i o n i s w a l k i n g a t a slow o r medium r a t e . 27. S u b m i s s i o n - A sea l i o n moves w i t h i t s head and body l o w e r e d . T h i s b e h a v i o u r i s d e s c r i b e d by S t i r l i n g (1970) f o r the New Ze a l a n d f u r s e a l and a s i m i l a r p a t t e r n i s d e s c r i b e d by S c h e n k e l (1967) f o r c a n i d s . 28. C h i n n i n g - A sea l i o n s u c c e s s i v e l y n i p s t h e c h i n , t h r o a t and neck o f a n o t h e r . 29. B a c k i n g - D u r i n g an i n t e r a c t i o n a sea l i o n goes t o the s i d e of the o t h e r a n i m a l and t r i e s t o l a y i t s head and neck on t h e o t h e r ' s back. 30. B e h i n d - During an i n t e r a c t i o n one s e a l i o n d e l i b e r a t e l y goes b e h i n d a n o t h e r . 31. S c r a t c h i n g - A sea l i o n s c r a t c h e s i t s e l f . 32. L o o k i n g - A sea l i o n i s l o o k i n g around. 16 33. S u c k l i n g - A sea l i o n s u c k s the t e a t o f a n o t h e r . 34. Coughing - A s e a l i o n coughs. T h i s p a t t e r n appears l a b o u r e d and p a i n f u l and may be accompanied ( f o r Z. c a l i f o r n i a n u s ) w i t h r e g u r g i t a t i o n of a white m i l k y f l u i d . T h i s b e h a v i o u r i s mentioned by P e t e r s o n and Bartholomew (1967) . 35. S h i v e r i n g - A s e a l i o n appears t o " s h i v e r " . 36. Attempted Mount - A s e a l i o n t r i e s t o mount a n o t h e r but f a l l s o f f a l m o s t i m m e d i a t e l y . 37. Mount - A s e a l i o n mounts a n o t h e r . METHODS OF DATA COLLECTION The q u a n t i t a t i v e d a t a were c o l l e c t e d i n two ways, (a) ENCOUNTER METHOD In the encounter method ( H a r e s t a d , 1973) a sea l i o n (which w i l l be r e f e r r e d t o as the p r i m a r y s e a l i o n ) i s s e l e c t e d and watched f o r a p p r o x i m a t e l y 30 minutes. During t h i s time p e r i o d a r e c o r d was made o f : 1. S p e c i e s and c l a s s of pri m a r y sea l i o n . 2. S p e c i e s and c l a s s o f sea l i o n s b e i n g i n t e r a c t e d w i t h (secondary sea l i o n s ) . 3. Which sea l i o n i n i t i a t e d the i n t e r a c t i o n 4. Behaviour p a t t e r n s used i n the i n t e r a c t i o n and sequence of use. 5. D u r a t i o n o f each b e h a v i o u r p a t t e r n . Only t h e b e h a v i o u r p a t t e r n sequence o f t h e primary sea l i o n c o u l d be re c o r d e d due to t h e speed w i t h which the 17 a n i m a l s moved d u r i n g an i n t e r a c t i o n . However, i n i t i a l and f i n a l b e h a v i o u r p a t t e r n s of the p r i m a r y and secondary s e a l i o n were r e c o r d e d f o r d e t e r m i n a t i o n of dominance h i e r a r c h i e s . (b) INDIVIDUAL DISTRIBUTION METHOD The i n d i v i d u a l d i s t r i b u t i o n method i n v o l v e d p e r i o d i c o b s e r v a t i o n s of a complete age-sex c l a s s o f an i m a l s on the h a u l o u t ground t o determine t h e i r "immediate" n e i g h b o u r s . The a c t i v i t y s t a t e of these a n i m a l s was a l s o d e t e r m i n e d . Immediate n e i g h b o u r s were t h o s e sea l i o n s l o c a t e d w i t h i n one body l e n g t h ( a p p r o x i m a t e l y 3 meters) o f the sea l i o n b e i n g observed. I f a n e i g h b o u r i n g s e a l i o n had i t s head r a i s e d i t was r e c o r d e d as a c t i v e . These d a t a c o u l d be compared w i t h a c t i v i t y c a l c u l a t i o n s made from t h e encounter method data so t h a t b i a s e s i n the c o l l e c t i o n methodology c o u l d be det e r m i n e d . G e n e r a l o b s e r v a t i o n s on i n f r e q u e n t behaviour p a t t e r n s , r e p r o d u c t i v e and t e r r i t o r i a l b e h a v i o u r , weather and u n g u a n t i f i a b l e e v e nts were a l s o made. O b s e r v a t i o n s of v o c a l b e h a v i o u r were not s y s t e m a t i c a l l y c o l l e c t e d but were noted when p o s s i b l e . PERIOD OF DATA COLLECTION O b s e r v a t i o n s were made October 5, 1974 t o May 2, were c o l l e c t e d between Oct 1975, d u r i n g which time a t the i s l a n d . A d d i t i o n a l per f o r 3 t o 4 days semimonthly from 1975. The m a j o r i t y o f t h e da t a ober 19, 1975 and December 20, l e a s t one o b s e r v e r was pr e s e n t on i o d i c o b s e r v a t i o n s were made from 18 F e b r u a r y 15, 1976 through A p r i l 19, 1976, and i n December, 1976. A t o t a l o f 642 hours of g u a n t i f i a b l e d i u r n a l o b s e r v a t i o n s and 169 hours o f n o c t u r n a l o b s e r v a t i o n s were t a k e n . I n a d d i t i o n , over 1,000 hours o f q u a l i t a t i v e d i u r n a l and n o c t u r n a l o b s e r v a t i o n s were made. N o c t u r n a l o b s e r v a t i o n was done w i t h a S t a r t r o n MK 303-A n i g h t v i s i o n scope. U n l e s s o t h e r w i s e s t a t e d , i t i s t o be assumed t h a t when u s i n g s t a t e m e n t s such as " g r e a t e r than e x p e c t e d " o r " l e s s than e x p e c t e d " , a s i g n i f i c a n c e l e v e l o f p < 0.05 i s a p p l i c -a b l e . 1 9 RESULTS Data c o l l e c t e d a t each s i t e were a n a l y z e d s e p a r a t e l y and are p r e s e n t e d under s e p a r a t e s t u d y s i t e s e c t i o n s . The s p e c i e s - a g e - c l a s s c o m p o s i t i o n a t each o b s e r v a t i o n s i t e was d i f f e r e n t , T h i s v a r i a n c e i n c l a s s d i s t r i b u t i o n and r e s u l t a n t v a r i a n c e i n b e h a v i o u r a t each h a u l o u t a r e a was l a r g e l y a p r o d u c t of topography and exposure o f t h e s i t e , I t i s hoped t h a t the d a t a p r e s e n t a t i o n method used w i l l g i v e an o v e r a l l view o f t h e b e h a v i o u r o f t h e s p e c i e s - a g e - c l a s s e s p r e s e n t a t each s i t e and a l l o w f o r comparisons o f b e h a v i o u r between a g e - c l a s s e s , s p e c i e s and study a r e a s . Each s t u d y s i t e s e c t i o n i s d i v i d e d i n t o s e v e r a l b e h a v i o u r h e a d i n g s which a r e used r e p e a t e d l y throughout t h e r e s u l t s and are l i s t e d e x t e n s i v e l y i n the t a b l e o f c o n t e n t s f o r c r e s s r e f e r e n c e . I t i s f e l t t h a t t h i s approach i s more s a t i s f a c t o r y than p r e s e n t i n g t h e i n d i v i d u a l b e h a v i o u r headings f o r a l l s i t e s c o n s e c u t i v e l y { i . e . C l a s s a s s o c i a t i o n s : S i t e a , S i t e B, S i t e I , S i t e H; C l a s s I n t e r a c t i o n s : S i t e a, S i t e B, S i t e I , S i t e B; e t c . ) s i n c e t h i s l a t t e r method would not as e a s i l y f a c i l i t a t e a comprehensive development o f t h e i n d i v i d u a l q u a n t i f i a b l e b e h a v i o u r p a t t e r n s i n t o an u n d e r s t a n d a b l e p r e s e n t a t i o n of o v e r a l l s e a l i o n b e h a v i o u r . 2 0 AREA A SITE DESCRIPTION Urea A ( F i g u r e 1) c o n s i s t s o f s o l i d r o c k benches, T h i s s i t e c o n t a i n s few f l a t a r e a s g r e a t e r than 9-10 . Thus d u r i n g most i n t e r a c t i o n s one a n i m a l i s l o c a t e d on a d i f f e r e n t p h y s i c a l l e v e l than i t s p a r t n e r . O b s e r v a t i o n s were made from b l i n d 1 a t a d i s t a n c e o f 10 t o 30 meters from the sea l i o n s . N i g h t o b s e r v a t i o n s s e r e not t a k e n s i n c e the r e s o l u t i o n of t h e S t a r t r o n made i t e x t r e m e l y d i f f i c u l t t o d i s t i n g u i s h between ECS and EYB, and ac c e s s t o Area A was p a r t i c u l a r l y t r e a c h e r o u s even d u r i n g the day and i m p o s s i b l e a t h i g h t i d e s o r d u r i n g h i g h s e a s . POPULATION STRUCTOEE AND DISTRIBUTION The sea l i o n p o p u l a t i o n o f Area A c o n s i s t e d e x c l u s i v e l y °f E. j u b a t u s (Table 1). No Z. c a l i f o r n i a n u s were observed on t h i s h a u l o u t a r e a . Few E. j u b a t u s pups were p r e s e n t . EIB, EYB and ECS were the predominant c l a s s e s . The BOB, ECS and EPS were l o c a t e d i n t h e middle o f Area A. T h i s r e g i o n of Area A c o n t a i n e d t h e h i g h e s t e l e v a t i o n and the most broken t e r r a i n . EIB »ere found on the sout h -e a s t s i d e where a c c e s s t o , and r e t r e a t f r o m , t h e c e n t r a l p o r t i o n was r e l a t i v e l y easy. Some o f the EYB were found i n the c e n t r a l p o r t i o n , but most were on the n o r t h s i d e of Area A which p r o v i d e d poor a c c e s s t o the c e n t r a l r e g i o n . Table 1. Area A. Age-sex s t r u c t u r e of sea l i o n c l a s s e s on h a u l -out area A. Numbers v a r i e d from 79 to 142 during observation periods. Test f o r homogeniety of p r o p o r t i o n s : X 2=18.3; P^O.05; df=15 Class P r o p o r t i o n Of Population EOB 0.14 EI B 0.30 EYB 0.28^ EPS 0.04 ECS 0.24 22 T e r r i t o r i a l b e h a v i o u r , w i t h defence o f p r e c i s e b o u n d a r i e s , as d e s c r i b e d by Gentry (1970) and Sandegren {1970), was not o b s e r v e d . S e v e r a l EOB were s i t e s p e c i f i c and would r e p e a t e d l y r e t u r n t o a c e r t a i n area o f t h e h a u l o u t ground but no d e f i n i t e b o u n d a r i e s were defended. ECS were c o n t i n u a l l y h a r a s s e d by EI B, and to a l e s s e r e x t e n t by EYB, but r a r e l y by EOB. I t may be as a r e s u l t o f t h i s t h a t f e m a l e s tended t o group i n a r e a s where EOB were l o c a t e d . EOB o f t e n p r o t e c t e d a group of f e m a l e s from harassment by EIB. T h i s p r o t e c t i o n a r e a v a r i e d i n s i z e and was p r o b a b l y d e t e r m i n e d by t h e d i s t a n c e t h a t the EOB's view was not o b s t r u c t e d , up t o a p p r o x i m a t e l y 8 meters, and more i m p o r t a n t , on the l e v e l n e s s of the t e r r a i n . The t e r r a i n s l o p e and c o n t i n u i t y was an i m p o r t a n t f a c t o r i n p r e v e n t i n g EOB g u i c k a c c e s s to EIB-ECS i n t e r a c t i o n s and o c c a s i o n a l l y p r e v e n t e d easy a c c e s s f o r EIB t o ECS. a l t h o u g h EIB were r a r e l y observed s l e e p i n g near EOB, o f t e n EOB were seen l y i n g i n c l o s e p r o x i m i t y t o each o t h e r w i t h no apparent a g g r e s s i o n d i s p l a y e d . Females h a r a s s e d by EIB would o f t e n move towards an EOB whereupon the EIB would u s u a l l y not f o l l o w i f t h e EOB r e a c t e d t o t h e EIB's p r e s e n c e . I f t h e EOB was s l e e p i n g , however, the EIB would o f t e n f o l l o w t h e f e m a l e . CLASS ASSOCIATIONS I f t h e sea l i o n s were randomly d i s t r i b u t e d t h e n the c l a s s c o m p o s i t i o n o f n e i g h b o u r s ( F i g u r e 2) would be s i m i l a r t o t h e f r e q u e n c i e s of c l a s s e s on Area A (Table 1 ) . However, EOB a s s o c i a t e w i t h themselves l e s s and ECS more than would be Figure 2. Area A. A s s o c i a t i o n . The proportion of neighbours ( w i t h i n 3 meters) belonging to c l a s s e s l i s t e d on the a b s c i s s a around i n d i v i d u a l s of c l a s s e s l i s t e d on the o r d i n a t e i s given. The expected frequency d i s t r i b u t i o n s are c a l c u l a t e d using Table 1. *male c l a s s e s lumped f o r X 2 c a l c u l a t i o n . 23 lOCn EOB n=53 X2=19.0 p<0.05 df=4 lOO-i EIB n=91 X2=68.5 P<0.05 df=k 0 1 OO-i EYB " n=88 X 2=24.3 p^O.05 df=4 0 100n EPS -0 100-ECS -0 lOO-i M BL n=25 XZ=k.O p >0.05 df=2* n=85 X2=20.4 p<0.05 df=k Expected 24 e x p e c t e d . EIB a s s o c i a t e w i t h t h e m s e l v e s more than expected and w i t h EOB, EYB and ECS l e s s t h a n e x p e c t e d . EYB a s s o c i a t e w i t h EIB l e s s and w i t h t h e m s l e v e s more than e x p e c t e d . The pups, a l l o f which were s u c k l i n g , a re always l o c a t e d near f e m a l e s , w h i l e ECS a s s o c i a t e with EOB and t h e m s e l v e s more than e x p e c t e d . CLASS INTERACTIONS INTERACTION DURATION AND FREQUENCY The t i m e s p e n t o b s e r v i n g each age-sex c l a s s p r e s e n t p l u s t h e minutes spent i n t e r a c t i n g , number of i n t e r a c t i o n s and v a r i o u s r a t e s c a l c u l a t e d from t h e s e d a t a are g i v e n i n T a b l e 2. EYB and EIB spend a g r e a t e r p r o p o r t i o n o f time i n t e r a c t i n g than do o t h e r c l a s s e s . T h i s i s a l s o r e f l e c t e d i n t h e i r h i g h i n t e r a c t i o n r a t e s and l a r g e d u r a t i o n of i n t e r a c t i o n s . The hig h d u r a t i o n of i n t e r a c t i o n v a l u e f o r EPS i s r e l a t e d t o t h e i r l e n g t h y s u c k l i n g p e r i o d s . Male i n t r a c l a s s i n t e r a c t i o n s a r e l o n g e r i n d u r a t i o n t h a n a r e male-male i n t e r c l a s s i n t e r a c t i o n s ( F i g u r e 3 ) . EOB-ECS i n t e r a c t i o n s a r e l o n g e r t h a n EIB-ECS i n t e r a c t i o n s . EYB-ECS i n t e r a c t i o n s a re s h o r t e r i n d u r a t i o n than e i t h e r EOB-ECS or EIB-ECS i n t e r a c t i o n s . A l l male-pup i n t e r a c t i o n s o b s e r v e d ( i n c l u d i n g t h e one r e c o r d e d ) were a p p r o x i m a t e l y 5 seconds or l e s s . Female-pup i n t e r a c t i o n s were l o n g i n d u r a t i o n because t h e s e i n t e r a c t i o n s were u s u a l l y s u c k l i n g p e r i o d s which l a s t e d up t o 15 m i n u t e s . Female-female i n t e r a c t i o n s were s h o r t i n d u r a t i o n (ca. 8 seconds) . I f the a n i m a l s i n t e r a c t e d randomly w i t h t h e i r 25 Table 2. Area A. Proport i o n of time spent i n t e r a c t i n g , i n t e r a c t i o n rate and average d u r a t i o n of an i n t e r a c t i o n , plus the data f o r c a l c u l a t i n g these rates are given f o r each sea l i o n c l a s s l i s t e d on the o r d i n a t e . Expected values f o r " X 2 " and " H " were determined from the r e l a t i v e proportions of time that each c l a s s was observed. "H" value i s c a l c u l a t e d using Kruska 1 -Via 1 1 i s one-way a n a l y s i s of variance. Class Minutes Observed Minutes P r o p o r t i o n Spent Of In t e r a c t i n g Time Spent I n t e r a c t i n g Number Of 1 n t e r a c t i o n s 1 n t e r a c t ion Rate: 1 n t e r a c t ions Per Minute Average Duration . Of An 1 n t e r a c t ion (Seconds) EOB 586 . 49.2 0.084 83 0.142 36 EIB 602 98. 1 0.163 149 0.248 39 EYB 615 140.8 0.229 163 0.265 52 EPS 638 79.3 0.124 12 0.019 396 ECS 1504 121.8 0.081 3^ 7 X2=146.6 p<0.05 df=4 0.231 21 H=30.2 p<0.05 df=4 Figure 3. Area A. Mean I n t e r a c t i o n Duration. The i n t e r a c t i o n d u r a t i o n i s given f o r the c l a s s l i s t e d on the ordin a t e when i n t e r a c t i n g w i t h the c l a s s l i s t e d on the absc i ssa. *sample s i z e too small f o r a n a l y s i s . ioo-i E O B H H=32.1 p <0.05 df=3 OO - i n= 5 37 21 20 E I B H I O O - I n= 31 10 1 51 H=72.1 p <0.05 df=3 . E Y B H H=89.9 p<0.05 df=3 400 • n= 25 13 E P S - } n = loon E C S H H=27.67 p<0.05 df=4 27 n e i g h b o u r s , t h e f r e q u e n c i e s of i n t e r a c t i o n s w i t h c l a s s e s ( F i g u r e 4) would be s i m i l a r t o the c l a s s c o m p o s i t i o n of n e i g h b o u r s ( F i g u r e 2 ) . The f r e q u e n c y d i s t r i b u t i o n s are not s i m i l a r . EOB i n t e r a c t w i t h EIB more than expected and w i t h EYB and ECS l e s s than e x p e c t e d . EIB i n t e r a c t w i t h o t h e r EIB l e s s than e x p e c t e d and w i t h EOB and ECS more than e x p e c t e d . EYB i n t e r a c t e d as e x p e c t e d . ECS i n t e r a c t w i t h EIB and EYB more than e x p e c t e d and with ECB and o t h e r ECS l e s s than e x p e c t e d . EPS spent most o f t h e i r t i me s u c k l i n g o r b e i n g i n c l o s e c o n t a c t w i t h f e m a l e s , and t h u s have a h i g h e r i n t e r a c t i o n r a t e w i t h females than e x p e c t e d . The pups on the h a u l o u t a r e a were never seen i n t e r a c t i n g w i t h o t h e r pups. Pups remain c l o s e l y a s s o c i a t e d w i t h t h e i r apparent mothers and v o c a l i z e l o u d l y i f t h e y become s e p a r a t e d from the mother. ACTIVITY FREQUENCY The p r o p o r t i o n o f t i m e spent a c t i v e f o r the v a r i o u s c l a s s e s was o b t a i n e d from d a t a c o l l e c t e d by both t h e e n c o u n t e r method and t h e i n d i v i d u a l d i s t r i b u t i o n method ( F i g u r e 5 ) . S i n c e the l a t t e r method u t i l i z e s o b s e r v a t i o n s on a whole age-sex c l a s s a t one time r a t h e r than supposed random s a m p l i n g o f i n d i v i d u a l s , I c o n s i d e r e d i t the most a c c u r a t e e s t i m a t e . As shown i n F i g u r e 5, r e s u l t s t a b u l a t e d by the i n d i v i d u a l d i s t r i b u t i o n method a r e c o n s i s t e n t l y lower t h a n t h o s e a c h i e v e d by t h e e n c o u n t e r method. T h i s i n d i c a t e s t h a t t h e r e was a b i a s towards o b s e r v i n g a c t i v e a n i m a l s d u r i n g c o l l e c t i o n o f t h e encounter method d a t a . Figure h. Area A. Interaction Frequency. The percentage value is the frequency with which classes l i s t e d on the ordinate engaged in interactions with the classes l i s t e d on the abscissa. Expected f r e -quencies are calculated using Figure 2. *sample size too small for analysis." obse rved expected PERCENT Figure 5- Area A. A c t i v i t y Frequency. If a sea : l i o n had i t s head r a i s e d i t was con-sidered a c t i v e . The percentage value represents the proportion of time that a sea l i o n had i t s head r a i s e d w h i l e i t was being observed (encounter method) or the proportion of sea l i o n s in each c l a s s that had t h e i r heads r a i s e d during p e r i o d i c counts of the haulout area ( i n d i v i d u a l d i s t r i b u t i o n method). Encounter Method H=l 1.6 p<0.05 d M Ind i v i d u a l D i s t r i but ion Method X2=25-2 p<0.05 df'=4 26 81 58 306 EPS ECS 30 BEGINNING AND TERMINATION BEHAVIOUR (1) INITIATION OF INTERACTIONS The advance r e p r e s e n t s an i n t e n t i o n a l low a g g r e s s i o n i n i t i a t i o n of an i n t e r a c t i o n . The user o f t h i s b e h a v i o u r p a t t e r n d i r e c t s i t m a i n l y at c l a s s e s o f s i m i l a r or younger age ( F i g u r e 6 ) . The advance i s used p r e d o m i n a n t l y by males. EOB and EIB use t h e advance i n over 50% of t h e i r i n t e r a c t i o n s w i t h ECS. In c o n t r a s t EYB use the advance i n o n l y 27% of t h e i r i n t e r a c t i o n s w i t h ECS. The f a s t advance r e p r e s e n t s an i n t e n t i o n a l h i g h a g g r e s s i o n i n i t i a t i o n o f an i n t e r a c t i o n . I t i s used o n l y by males (Table 3) and i s d i r e c t e d most o f t e n at younger or s m a l l e r age c l a s s e s . D i r e c t i o n o f f a s t advance towards f e m a l e s r e s u l t s i n immediate move away by t h e f e m a l e s . EOB do not d i r e c t the f a s t advance a t ECS. EIB and EYB use t h e f a s t advance o n l y o c c a s i o n a l l y when i n t e r a c t i n g w i t h ECS. (2) INTENTIONAL INITIATION AND DOMINANCE RELATIONSHIPS A l l i n t e r a c t i o n s b e g i n n i n g w i t h advance o r f a s t advance w i l l be d e f i n e d as b e i n g i n t e n t i o n a l l y i n i t i a t e d . The s o c i a l p a r t n e r s t a r t i n g each i n t e n t i o n a l l y i n i t i a t e d i n t e r a c t i o n i s g i v e n i n Table 4. O c c a s i o n a l l y both p a r t n e r s d i s p l a y the advance b e h a v i o u r , t h u s even though o n l y 32 i n t e r a c t i o n s took p l a c e between EPS and ECS, Table 4 i n d i c a t e s t h a t t h e r e were 34. No i n t e n t i o n a l i n i t i a t i o n s were obser v e d f o r i n t e r a c t i o n s between EPS and EOB, EIE, EYB o r o t h e r EPS. A l l r e c o r d e d i n t e r a c t i o n s between EPS and ECS appeared i n t e n t i o n a l l y i n i t i a t e d by a t l e a s t one o f the p a r t n e r s and were p l a c e d under the advance c a t e g o r y even Figure 6. Area A. Advance. The frequency of use the advance is given f o r c l a s s e s l i s t e d on the o r d i n a t e while i n t e r a c t i n g w i t h c l a s s e s l i s t e d on the a b s c i s s a , "'sample s i z e too small f o r a n a l y s i s . 31 100 EOB n= 100" 68 II 46 61 X2=1.4 p=»0.05 df-3 EYBH X 2 = 3 8 . 9 p « = 0 . 0 5 df=3 . n= 100-1 EIB-1 n= 100 EPS H 100" ECSH n= 68 46 57 11 23 23 79 141 0 1 0 0 32 1*1 1 P 61 185 141 32 5 6 EOB EIB EYB EPS ECS X2=18.1 p < 0 . 0 5 df=3 X 2=27.3 p <0.05 df-3 32 Table 3. Area A. Fast Advance. " R a t i o " i s the number of times that the f a s t advance was used by the c l a s s l i s t e d on the ord-inate over the number of times i t was used by the c l a s s l i s t e d on the a b s c i s s a when the two c l a s s e s were i n t e r a c t i n g . EIB EYB ECS EOB 11/2 5/0 0/0 EIB 2/0 3/0 EYB 1/0 33 Table k. Area A. I n t e n t i o n a l I n i t i a t i o n . I n t e n t i o n a l i n i t i a t i o n of i n t e r a c t i o n s using advance and f a s t advance behaviour. " R a t i o " i s the number of i n t e r a c t i o n s i n t e n t i o n a l l y i n i t i a t e d by the c l a s s l i s t e d on the o r d i n a t e oyer those i n t e n t i o n a l l y i n i t -i ated by the c l a s s l i s t e d on the a b s c i s s a w h i l e the two c l a s s e s were i n t e r a c t i n g . EIB EYB ECS EOB 41/8 21/2 31/3 EIB 13/6 131/8 EYB 39/33 EPS 28/6 34 though the c o n t e x t of the advance i s perhaps d i f f e r e n t from t h a t used d u r i n g o l d e r a n i m a l i n t e r a c t i o n s . H a r e s t a d (1973) h y p o t h e s i z e s t h a t "sea l i o n s s h o u l d t e n d t o i n i t i a t e i n t e r a c t i o n s w i t h s u b o r d i n a t e s more than they do w i t h dominants." I f t h i s were t r u e T a b l e 4 i n d i c a t e s t h a t EPS are dominant t o ECS. G e n e r a l o b s e r v a t i o n s , however, i n d i c a t e t h a t EPS are s u b o r d i n a t e t o a l l c l a s s e s . F u r t h e r a p p l i c a t i o n of Har e s t a d ' s (1973) h y p o t h e s i s t o Tab l e 4 shows t h a t EOB are dominant to a l l c l a s s e s , EIB a r e s u b o r d i n a t e o n l y t o EOB, w h i l e EYE are s l i g h t l y dominant t o ECS. Table 5 demonstrates t h e r e l a t i o n s h i p of dominance and s u b o r d i n a n c e i n the i n t e n t i o n a l i n i t i a t i o n of i n t e r a c t i o n s under t h e c r i t e r i o n l i s t e d above. (3) MOVE AWAY AND DOMINANCE RELATIONSHIPS The use of move away to determine dominance h i e r a r c h y i n Mirounga a u g u s t i r o s t u s was proposed by LeBoeuf and P e t e r s o n (1968). S u b o r d i n a t e s are ex p e c t e d t o use move away at t h e t e r m i n a t i o n of an i n t e r a c t i o n more o f t e n than a re dominants. The f r e q u e n c y of i n t e r a c t i o n s t e r m i n a t i n g i n move away b e h a v i o u r , f o r each c l a s s , i s g i v e n i n T a b l e 6. T h i s b e h a v i o u r i s used e x t e n s i v e l y i n male-male i n t e r a c t i o n s , l e s s so i n male-female i n t e r a c t i o n s and l e a s t i n female-pup and f e m a l e - f e m a l e i n t e r a c t i o n s , T a b l e 7 g i v e s the r e l a t i v e use o f move away by each c l a s s d u r i n g i n t e r c l a s s i n t e r a c t i o n s . A p p l i c a t i o n of LeBoeuf and P e t e r s o n ' s (1968) h y p o t h e s i s shows t h a t EOB a r e 35 Table 5- Area A. R e l a t i o n s h i p of i n t e n t i o n -a l l y i n i t i a t e d i n t e r a c t i o n s to dominance h i e r a r c h y . Number of i n t e r a c t i o n s where i n t e n t i o n a l i n i t i a t i o n d i d and d i d not occur is given and compared. X 2=l53.i; p<0.05; d f = l . Dominant To Subord i nate Subord i nate To Dom i nant Number Of Intent iona11y In i t iated Interact ions 304 66 Number Of Interact ions Not Intent i o n a l l y In? t iate d 220 458 Frequency Of Use 0.580 0. 126 Table 6. Area A. Move Away. Use of move away during i n t e r a c t i o n s i n v o l v i n g c l a s s e s l i s t e d on the ord i n a t e and c l a s s e s l i s t e d on the a b s c i s s a . The number of i n t e r a c t i o n s where move away di d and did not occur i s given. * sample not used in c a l c u l a t i o n of value. X2=67.7; p<0.05; df=10. EOB EIB EYB EPS ECS EOB Move Away 4 4 6 39 0 18 No Move Away 1 22 5 0 44 Frequency Of Use 0.800 O.676 0.848 _* 0.290 EIB Move Away 3.6 17 1 92 No Move Away 21 6 0 93 Frequency Of Use 0.632 0.739 1 .00* 0.497 EYB Move Away 27 0 76 No Move Away 52 0 65 Frequency Of Use 0.341 ~v 0.539 EPS Move Away 0 2 No Move Away 0 30 Frequency Of Use O.O63 ECS Move Away 3 No Move Away 53 Frequency Of Use 0.054 37 Table J. Area A. Determination of hi e r a r c h y using move away. The " r a t i o " i s the number of times move away was used by the c l a s s l i s t e d on the ord-inate over the number of times i t was used by the c l a s s l i s t e d on the a b s c i s s a when the two c l a s s e s were i n t e r -a c t i n g . E IB EYB EPS ECS EOB 2/kk 0/39 0/0 0/18 EIB 3/14 0/1 hi 88 EYB 0/0 3 3 A 3 EPS 2/0 38 dominant to a l l classes. EIB are subordinate only to EOB. EYB are s l i g h t l y dominant to ECS. ECS are dominant only to EPS. This relationship i s shown in Figure 7 . Except for pups, these r e s u l t s are si m i l a r to the hierarchy relationship determined with i n i t i a t i o n as the c r i t e r i o n for dominance. (4) FOLLOW The follow indicates that one of the partners wishes to prolong the inte r a c t i o n . By d e f i n i t i o n , follow takes place i n conjunction with move away. The rel a t i o n s h i p of follow to move away for each class i s shown i n Table 8. Males use the follow only rarely towards dominant males and most frequently when intera c t i n g with s l i g h t l y subordinate males. EIB use the follow pattern more than any other class when interacting with ECS, and would l i k e l y use i t even more frequently i f EOB did not intervene in EIB-ECS interactions. Pups do not use the follow as defined here. Females use the follow only r a r e l y , d i r e c t i n g i t only at those EYB which are smaller than themselves. INVESTIGATIVE BEHAVIOOfi Investigative behaviour i s used extensively i n female-pup interactions (Figure 8). I t i s also used i n . female-female interactions and male-female interactions, mainly by the older b u l l s . EOB do not e x i b i t investigative behaviour when interacting with other EOB but do when i n t e r a c t i n g with younger b u l l s . Males rarely use investigative behaviour towards older males. Figure 7- Area A. Dominance hier a r c h y f o r c l a s s e s as e s t a b l i s h e d by the use of the move away behaviour p a t t e r n . EOB EIB EYB ECS EPS Dominant Subord inant 40 Table 8. Area A. Follow. Use of fo l low by classes l i s t ed on the ordinate while interact ing with classes l i s t ed on the abscissa. Number times that the partner on the abscissa moved away from the partner on the ordinate and the number of times that the partner on the ordinate sub-siquently followed are given. ,*male classes grouped for X 2 analys i s . **sample too small for analys i s . EOB EIB EYB ECS EOB Follow Move Away Frequency Of Use 2 4 0.500 29 44 0.659 6 39' 0. 154 8 1 8 0.444 X2=l2.38 p <0.05 df=3 EIB Follow Move Away Frequency Of Use 0 2 0.000 16 36 0.444 9 14 . 0.643 51 88 0.580 x2=i.34 p > 0. 0 5 df=3 EYB Fol1ow Move Away Frequency Of Use 0 0 1 3 0.333 9 27 0.333 7 ^3 o. 163 X2=2.18 p>0.05 df=1* ECS Follow Move Away Frequency Of Use 0 0 0 4 0.000 4 33 0.121 0 3 0.000 Figure 8. Area A. I n v e s t i g a t i v e Behaviour. Percentage of i n t e r a c t i o n s during which the c l a s s l i s t e d on the o r d i n a t e used i n v e s t i g a t i v e behaviour w h i l e i n t e r a c t i n g with c l a s s e s l i s t e d on the a b s c i s s a . *sample s i z e too small f o r a n a l y s i s . IOC-. EOB 100-, 37 21 X2=10.9 p <0.05 df=3 EIB 4 X 2=14.7 p<0.05 df=3 • 100-] n= 31 57 10 EYB H 100-1 n= 2 5 1 3 79 46 X2=5.9 p >0.05 df=3 EPS n= loon ECS H n= 41 134 95 56 X2=19.1 p<0.05 df=4 EOB EIB EYB EPS ECS 42 NON-BODY AND BODY CONTACT BEHAVIOUR Duri n g i n t r a c l a s s i n t e r a c t i o n s EOB use p r e d o m i n a n t l y non-body c o n t a c t b e h a v i o u r p a t t e r n s (Table 9) . T h i s i s a l s o the case f o r females i n i n t r a c l a s s i n t e r a c t i o n s . EYB use p h y s i c a l body c o n t a c t b e h a v i o u r when i n t e r a c t i n g w i t h o t h e r EYB but use i n c r e a s i n g p r o p o r t i o n s of non-body c o n t a c t b e h a v i o u r when i n t e r a c t i n g w i t h o l d e r age c l a s s e s . EOB use d e c r e a s i n g p r o p o r t i o n s of non-body c o n t a c t behaviour when i n t e r a c t i n g w i t h younger male age c l a s s e s . Females are p r e d o m i n a n t l y non-body c o n t a c t a n i m a l s and use non-body c o n t a c t b e h a v i o u r w i t h o l d e r males but use more body c o n t a c t b e h a v i o u r w i t h the younger males. MISCELLANEOUS BEHAVIOUR ^ (1) MOUNTING Duri n g t h e 100-plus hours o f o b s e r v a t i o n on Area A, no c o p u l a t i o n s were o b s e r v e d , but s e v e r a l attempted mounts and s u c c e s s f u l mounts by EIB and EYB were observed (Table 10) l a s t i n g up t o 12 seconds and i n v o l v i n g p e l v i c t h r u s t s - EOB d i d not a t t e m p t mounting. These d a t a were n o t c o l l e c t e d as p a r t o f the encounter method d a t a but were g e n e r a l o b s e r v a t i o n s . Of the 15 r e c o r d s of attempted c o p u l a t i o n s f o r EIB, 9 were performed by one i n d i v i d u a l over a 2.5 h r . time span. EYB appeared more t o l e r a n t of t h e EIB attemped mounts than were females which t r i e d t o move away as soon as the males t r i e d t o mount them. Of t h e 6 attempted mounts by EYB, 5 were done by one i n d i v i d u a l o v er a 1 h r . p e r i o d . Table 9. Area A. Non-body And Body Contact. Use of non-body and body contact behaviour patterns by the c l a s s e s l i s t e d on the o r d i n a t e while i n t e r a c t i n g with the c l a s s e s l i s t e d on the a b s c i s s a . The number of non-body and body contact behaviour patterns used are given and compared, "'sample not used in c a l c u l a t i o n of value. X2=426.9; p<0.05; df=l7-EOB EIB EYB EPS ECS EOB Non-body Contact 72 198 31 0 104 Body Contact 51 186 51 0 31 Proportion of Non-body Contact 0.585 0.516 0.378 0.722 EIB Non-body Contact 108 327 52 0 289 Body Contact 176 576 108 0 237 Proportion of Non-body Contact 0.382 0.358 0.325 0.549 EYB Non Body Contact 76 94 302 0 33 Body Contact 134 218 1286 0 84 P r o p o r t i o n of Non-body Contact 0.362 O.301 0.190 O.282 EPS Non-body Contact 0 0 0 0 3 Body Contact 0 0 0 0 12 P r o p o r t i o n of Non-body Contact —~" 0.200 ECS Non-body Contact 132 321 181 6 85 Body Contact 46 278 219 2 23 Proportion of Non-body Contact 0.742 0.536 0.453 0.750 0.787 4 4 Table 10. Area A. Mounts. Number of attempted and successful mounts is given for classes on the ordinate which directed the behaviour at classes l i s t ed on the absc i ssa. EIB Attempted Mounts Mounts EYB Attempted Mounts Mounts EIB EYB' ECS 2 4 6 0 2 1 0 3 3 0 0 0 45 AREA B SITE DESCRIPTION Area B ( F i g u r e 1) c o n s i s t s of s o l i d rock, benches. A l t h o u g h i t i s somewhat f l a t t e r than Area A, t h e r e a re no e x t e n s i v e f l a t areas p r e s e n t . Access from t h e water i s d i f f i c u l t f o r sea l i o n s a t a l l t i m e s except by way of two r a v i n e c o r r i d o r s . D i u r n a l and n o c t u r n a l o b s e r v a t i o n s were made from b l i n d 2, which was 10 to 50 meters from t h e sea l i o n s . POPULATION STRUCTURE EOB were t h e o n l y sea l i o n s observed on t h i s a r e a , w i t h the e x c e p t i o n o f one i n s t a n c e mentioned below. No Z. c a l i f o r n i a n u s were p r e s e n t . The numbers of EOB- v a r i e d from about 50 t o 85 d u r i n g the p e r i o d s of d a t a c o l l e c t i o n . CLASS ASSOCIATIONS The EOB were e x t r e m e l y t o l e r a n t of one a n o t h e r , u n l i k e t h e s i t u a t i o n on the b r e e d i n g r o o k e r y , o f t e n t o u c h i n g a neighbour but g e n e r a l l y m a i n t a i n i n g an i n d i v i d u a l d i s t a n c e of a few meters. Defence of an area was observed o n l y once. On November 4, 1975, a s i t e a t t h e head o f an a c c e s s r a v i n e , g e n e r a l l y o c c u p i e d by 3 t o 4 EOB, was used as an h a u l o u t by f i v e ECS. As the cows s t a r t e d t o h a u l o u t , one EOB (not the l a r g e s t ) 46 s t a r t e d c h a s i n g the o t h e r b u l l s away from t h e a r e a . There was v e r y l i t t l e r e s i s t a n c e from the o t h e r b u l l s which moved a few meters away and went t o s l e e p . Although no o t h e r EOB t r i e d t o e n t e r t h i s a r e a , over a p e r i o d of 8.5 h o u r s , 18 EIB t r i e d t o g a i n a c c e s s t o t h e f e m a l e s . Some of t h e s e a t t e m p t s may have been r e p e a t s by the same EIB. EIB were f o r c e d t o attempt l a n d e n t r y , due t o s h o r e l i n e topography, v i a t h e r e s t r i c t i v e r a v i n e c o r r i d o r s . In a l l i n s t a n c e s the EOB chased t h e EIB away, e i t h e r by t h r e a t e n i n g w i t h head nodding o r a f a s t advance. The EIB always r e t r e a t e d b e f o r e body c o n t a c t c o u l d o c c u r . J u s t b e f o r e dark (1637 hr.) one of t h e females e n t e r e d the water. W i t h i n 8 minutes a l l of the o t h e r females had d e p a r t e d . The EOB made no a t t e m p t to s t o p them. The next morning a t 0800 hr. t h e above mentioned o l d b u l l and two o t h e r EOB were s l e e p i n g i n the "defended a r e a " . T h i s i n s t a n c e i s t h e o n l y time t h a t a n i m a l s o t h e r than EOB were seen on Area B. No EIB or EYB, o t h e r than those mentioned above, t r i e d t o h a u l out on Area B, a l t h o u g h they were seen o b s e r v i n g t h e a c c e s s r a v i n e s , and EOB, from t h e water's edge. CLASS INTERACTIONS INTERACTION DURATION The t i m e spent o b s e r v i n g i n Area B, minutes spent i n t e r a c t i n g , number of i n t e r a c t i o n s and r a t e s c a l c u l a t e d from these d a t a are g i v e n i n T a b l e 11. A comparison w i t h t h e EOB d a t a of T a b l e 2 shows t h a t both the p r o p o r t i o n of 4 7 Table 11. Area B. Proport i o n of time spent i n t e r a c t i n g , i n t e r a c t i o n rate and average du r a t i o n of an i n t e r a c t i o n , plus the data f or c a l c u l a t i n g these rates are given f o r d i u r n a l and nocturnal observations of EOB on area B. "D" value is c a l c u l a t e d using K61mogorov-Smirnov two-way t e s t f o r a n a l y s i s of variance. Class Minutes Minutes P r o p o r t i o n Number I n t e r a c t i o n Average Observed Spent Of Of Rate: Duration I n t e r a c t i n g Time Spent I n t e r a c t i o n s I n t e r a c t i o n s Of An In t e r a c t i n g Per Minute I n t e r a c t i o n (Seconds) Day 5427 146.5 0.027 234 0.043 38 Night 1114 34.5 0.031 57 0.051 35 X2=1.33 D=0.073-p>0.05 p>0.05 df=l n]=234 n2=57 48 t i m e s p e n t i n t e r a c t i n g and the i n t e r a c t i o n r a t e a r e much low e r f o r EOB on Area B. The average d u r a t i o n of an i n t e r a c t i o n f o r EOB on Area B was 37 seconds (Table 11) as opposed t o 106 seconds f o r EOB on Area A ( F i g u r e 3 ) . ACTIVITY FREQUENCY There i s no s i g n i f i c a n t d i f f e r e n c e i n t h e a c t i v i t y on Area B d u r i n g hours o f l i g h t and darkness (Table 11 and F i g u r e 9 ) , t h u s where p o s s i b l e , d i u r n a l and n o c t u r n a l d a t a have been combined. F i g u r e 9 i n d i c a t e s t h a t f o r EOB , the o v e r a l l p r o p o r t i o n o f t i m e s p e n t a c t i v e cn Area B was lo w e r than f o r EOB on Area A (see F i g u r e 5) . BEGINNING AND TEEHINAT!ON BEHAVIOUR (1) INITIATION OF INTERACTIONS The use of advance and f a s t advance f o r the i n i t i a t i o n of i n t e r a c t i o n s i s compared i n T a b l e 12. There i s no s i g n i f i c a n t d i f f e r e n c e i n the f r e q u e n c y o f use o f t h e s e two p a t t e r n s (X^ = 1.91, p<0.05, df= 1 ) . S i n c e the advance and f a s t advance are m u t u a l l y e x c l u s i v e , 16% of a l l e n c o u n t e r s on Area B were i n t e n t i o n a l l y i n i t i a t e d . (2) HOVE AWAY AND FOLLOW The move away b e h a v i o u r p a t t e r n was used i n f r e q u e n t l y (Table 13). T h i s v a l u e i s much l o w e r t h a n the i n t r a c l a s s v a l u e f o r EOB on Area A (0.800, T a b l e 6 ) . I f one o f the p a r t n e r s d i d demonstrate t h e move away b e h a v i o u r d u r i n g an i n t e r a c t i o n , t h e o t h e r p a r t n e r would o f t e n f o l l o w (Table 13). Figure 9. Area B. A c t i v i t y Frequency. If a sea l i o n had i t s head r a i s e d i t was con-sidered a c t i v e . The percentage value represents the proportion of time that a sea l i o n had i t s head r a i s e d while i t was being observed (encounter method) or the proportion of sea l i o n s in each c l a s s that had t h e i r heads ra i s e d during p e r i o d i c counts of the haulout area ( i n d i v i d u a l d i s t r i b u t i o n method). Values are f o r day hours of observation and night hours of obser-v a t i o n . 49 15-1 I OH z LU O QH LU 0-5 1 n= 186 1423 DAY 42 462 NIGHT Encounter Method D=0.16 p >0.05 n!=l86 n 0 =42 Ind i v i d u a l D i s t r ibut ion Method X 2=2.12 p >0.05 df=1 Table 12. Area B. Use of the advance and f a s t advance behaviour patterns f o r i n i t i a t i o n of i n t e r a c t i o n s between EOB. The number of times that the behaviour pat-terns are used and are not used i s given. Advance Fast Advance Behav iour P a t t e r n Used 235 206 Not Used 3^ 7 376 Frequency Of Use 0.404 0.354 51 Table 13- Area B. Use of move away and f o l l o w by EOB. The number of times that the behaviour patterns are and are not used i s given. Move Away Follow Behav iour P a t t e r n Used Not Used Frequency Of Use 57 32 290 25 O.196 O.56I 52 INVESTIGATIVE BEHAVIGUR I n v e s t i g a t i v e b e h a v i o u r was not observed d u r i n g EOB i n t r a c l a s s i n t e r a c t i o n s . I n v e s t i g a t i v e b ehaviour was d i r e c t e d , however, at t h e group of fe m a l e s {see above) t h a t h a u l e d out on Area B. T h i s i n v o l v e d n o s i n g A, B and C and was most n o t i c e a b l e when the f e m a l e s had f i r s t h a u l e d o u t . T h i s b e h a v i o u r i s c o n s i s t e n t w i t h t h a t of EOB on Area A. NON-BODY AND BODY CONTACT BEHAVIOUR A l l f i v e t y p e s of non-body c o n t a c t and a l l e i g h t t y p e s of body c o n t a c t b e h a v i o u r were ob s e r v e d . Non-body c o n t a c t b e h a v i o u r was used more o f t e n t h a n body c o n t a c t b e h a v i o u r (Table 14). S i n c e a non-body c o n t a c t b e h a v i o u r p a t t e r n u s u a l l y i n v o l v e s more t i m e t h a n a body c o n t a c t b e h a v i o u r p a t t e r n , an even g r e a t e r p r o p o r t i o n of t h e i n t e r a c t i o n time i s spent i n non-body c o n t a c t b e h a v i o u r than i n body c o n t a c t b e h a v i o u r (Table 15). Only 1% of the i n t e r a c t i o n t i m e was spent engaged i n behaviour p a t t e r n s o t h e r than t h o s e from the non-body and body c o n t a c t c a t e g o r i e s . MISCELLANEOUS BEHAVIOUR (1) MOUNTING No a t t e m p t s were made by EOB t o c o p u l a t e w i t h o t h e r EOB or w i t h the ECS t h a t hauled out on Area B. Table 14. Area B. The number of times that non-body and body contact behav-iour patterns were used i s given and compared. X 2=l78. 6; p<0.05; df=1 . Non-body Contact 2864 Body Contact 1938 P r o p o r t i o n Of Non-body Contact 0.596 54 T a b l e . 1 5 . Area B. The r e l a t i o n -ship of time spent in non-body contact and body contact behaviour patterns to t o t a l time that EOB spent i n t e r -a c t i n g i s given. Time Spent In Non-body Contact Behav i ou r (Seconds) Time Spent In Body Contact Behav i ou r (Seconds) 77^2 2325 P r o p o r t i o n Of Total I n t e r a c t i o n Time Spent In Non-body Contact Behaviour 0.713 P r o p o r t i o n Of Total I n t e r a c t i o n Time Spent In Body Contact Behaviour 0.214 P r o p o r t i o n Of Total I n t e r a c t i o n Time Spent In E i t h e r Non-body Or Body Contact Behaviour 0.927 55 &BEA I SITE DESCRIPTION Area I ( F i g u r e 1) i s a b o u l d e r beach w i t h f l a t r o c k benches on i t s e a s t e r n s i d e . A n i m a l s have easy a c c e s s t o and from t h e water. The bay i s w e l l s h e l t e r e d and a l t h o u g h t h e r e i s r e l a t i v e l y l i t t l e beach a r e a , the sea l i o n s are a b l e t o keep above t h e r e a c h o f the waves and sea spray. O b s e r v a t i o n s were made from b l i n d 5 from a d i s t a n c e o f 20 t o 40 meters. N i g h t o b s e r v a t i o n s were not taken because of t h e d i f f i c u l t y i n g a i n i n g a c c e s s t o Area I , and because of the h i g h c l i f f s and darkness of the bay. POPULATION STRUCTURE Zalophus c a l i f o r n i a n u s was t h e predominant sea l i o n found on t h i s a r e a . Two or t h r e e EOB were o f t e n p r e s e n t but EIB and EYB were r a r e l y s e e n . For t h i s r e a s o n data c o l l e c t i o n was r e s t r i c t e d t o Z. c a l i f o r n i a n u s i n t r a s p e c i f i c i n t e r a c t i o n s . The g e n e r a l p o p u l a t i o n s t r u c t u r e i s g i v e n i n T a b l e 16. There were a p p r o x i m a t e l y one and o n e - h a l f t i m e s as many ZIB as ZYB d u r i n g any g i v e n p e r i o d . CLASS ASSOCIATIONS A random c l a s s a s s o c i a t i o n would approximate T a b l e 16. Table 16. Area I. Class s t r u c t u r e of 2. ca1iforn ianus on haulout area. Numbers v a r i e d from 55 to 107 during observation per iods. Test f o r homogeniety of proportions: X2=24.38; P>0.05; df =15-Class P r o p o r t i o n Of Population ZIB 0.63 ZYB 0.37 57 F i g u r e 10 i n d i c a t e s t h a t t h e r e i s no s e l e c t i v e c l a s s a s s o c i a t i o n as was found f o r E. j u b a t u s c l a s s e s (see F i g u r e 2 ) . CLASS INTERACTIONS INTERACTION DURATION AND FREQUENCY The minutes o b s e r v e d , minutes s p e n t i n t e r a c t i n g , number of i n t e r a c t i o n s and v a r i o u s r a t e s d e r i v e d from t h e s e d a t a are g i v e n i n T a b l e 17. The p r o p o r t i o n of time spent i n t e r a c t i n g , i n t e r a c t i o n r a t e s and average d u r a t i o n of i n t e r a c t i o n s a r e the l o w e s t v a l u e s found f o r any c l a s s on the i s l a n d (see T a b l e s 2, 11 and 2 2 ) . Zalophus c a l i f o r n i a n u s i n t e r a c t randomly w i t h t h e i r n e i g h b o u r s ( F i g u r e 11). The m a j o r i t y o f t h e i n t e r a c t i o n s r e c o r d e d were s t e r e o t y p e d , o f r e l a t i v e l y s h o r t d u r a t i o n (8 t o 10 seconds) and s i m i l a r t o the i n t e r a c t i o n s d e s c r i b e d by Pe t e r s o n and Bartholomew (1967), O r r (1965) and Schusterman (1968). 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 would be: Sea l i o n A i s s l e e p i n g and i s approached and d i s t u r b e d by sea l i o n B. No apparent i n t e n t o f a g g r e s s i o n i s shown by B. A t u r n s h i s head t o f a c e B and performs the mouth be h a v i o u r p a t t e r n . B r e c i p r o c a t e s the mouth p a t t e r n and e i t h e r moves s l i g h t l y away or l i e s down, i g n o r i n g A. A c l o s e s i t s mouth and goes back t o s l e e p , ending the i n t e r a c t i o n . O f t e n i f an i n d i v i d u a l r o l l s over w h i l e s l e e p i n g , or coughs i n a crowded a r e a , a s e r i e s o f s h o r t i n t e r a c t i o n s occur i n v o l v i n g the mouth or c r o s s mouthing 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 e i n t e r a c t i o n s appear t o be i n i t i a t e d w i t h no d i r e c t e d Figure 10. Area I. A s s o c i a t i o n . The proportion of neighbours ( w i t h i n 3 meters) in c l a s s e s l i s t e d on the a b s c i s s a around i n d i v i d u a l s of c l a s s e s • 1 i s t e d on the ord i n a t e i s given. The expected frequencies are c a l c u l a t e d using Table 16. observed expected 58 1 OO—i ZIB H n=357 X2=3.50 p >0.05 df=1 U J (_> 100-ZYB H n=2l6 X2=0.71 p >0.05 df =1 ZIB ZYB 59 Table 17. Area I. Proportion of time spent interact ing, interact ion rate and average duration of an interact ion, plus the data for ca lcu lat ing these rates are given for both sea l i on classes l i s t ed on the ordinate. Class Mi nutes Observed ZIB ZYB 3868 2352 Minutes Proportion Spent Of Interacting Time Spent Interacting 69.9 56.3 0.018 0.024 Number Interaction Of Rate: Interactions Interactions Per Minute 395 285 X2=4.90 p <0.05 df=l 0. 102 0.122 Average Durat ion Of An Interact i on (Seconds) 10 13 D=0. 118 p <0.05 n]=395 n2=285 Figure 11. Area I. I n t e r a c t i o n Frequency. The frequency wit h which c l a s s e s l i s t e d on the o r d i n a t e engaged in i n t e r a c t i o n s w i t h c l a s s e s l i s t e d on the a b s c i s s a i s given. Expected frequencies are c a l c u l a t e d using Table 16. observed expected 60 loo n Z I B —I n= U J o 100 - l 117 X 2=3.14 P>0.05 df=1 Z Y B n= 167 ZIB X2=2.Mf p >0.05 df=1 61 a g g r e s s i v e i n t e n t , and s i n c e t h e c l a s s e s are randomly d i s t r i b u t e d ( F i g u r e 10) i t i s l o g i c a l t h a t t h e m a j o r i t y of the c l a s s i n t e r a c t i o n s would a l s o be random. The v a l u e s g i v e n i n F i g u r e 12 f o r d u r a t i o n of i n t e r a c t i o n s a r e comparable t o th o s e c a l c u l a t e d f o r ECS i n t r a c l a s s i n t e r a c t i o n s (see F i g u r e 3) and are among the l o w e s t found f o r any c l a s s on the i s l a n d . There i s no s i g n i f i c a n t d i f f e r e n c e between the i n t e r or i n t r a c l a s s i n t e r a c t i o n d u r a t i o n s f o r 2. c a l i f o r n i a n u s cn Area I . ACTIVITY FREQUENCY There i s no s i g n i f i c a n t d i f f e r e n c e between the pe r c e n t a g e s o f time s p e n t a c t i v e by the two 2. c a l i f o r n i a n u s c l a s s e s ( F i g u r e 13). As was shown i n F i g u r e 5, the enc o u n t e r method produces h i g h e r r e s u l t s than does t h e i n d i v i d u a l d i s t r i b u t i o n method. BEGINNING AND TERMINATION BEHAVIOUR (1) INITIATION OF INTERACTIONS Male 2. c a l i f o r n i a n u s use the advance much l e s s f r e q u e n t l y (Table 18) than do male E. j u b a t u s ( F i g u r e 6 and Tabl e 12). There i s no s i g n i f i c a n t d i f f e r e n c e i n the use of advance d u r i n g i n t r a or i n t e r c l a s s i n t e r a c t i o n s . The f a s t advance was not used by 2. c a l i f o r n i a n u s on Area I . (2) MOVE AWAY AND FOLLOW Du r i n g t h e 284 i n t e r c l a s s i n t e r a c t i o n s r e c o r d e d , 2YB moved away from 2IB 32 t i m e s , w h i l e ZIB moved away from ZYB o n l y 9 t i m e s (X ^  = 12.90, p<0.05, df= 1). A c c o r d i n g t o Figure 12. Area I. Mean Interaction Duration. The interact ion duration is given for the class l i s t ed on the ordinate while • interact ing with the class l i s t ed on the abscissa. 62 20-. D=0.092 p>0.05 D=1.59 p>0.05 F i g u r e 13- A r e a I. A c t i v i t y F r e q u e n c y . I f a sea l i o n had i t s head r a i s e d i t was con-s i d e r e d a c t i v e . The p r o p o r t i o n o f ti m e t h a t a sea l i o n had i t s head r a i s e d w h i l e i t was b e i n g o b s e r v e d ( e n c o u n t e r method) o r the p r o p o r t i o n o f sea l i o n s i n each c l a s s t h a t had t h e i r heads r a i s e d d u r i n g p e r i o d i c c o u n t s of the h a u l o u t a r e a ( i n d i v i d u a l d i s t r i b u t i o n method) i s g i v e n . 63 15-1 10H o CC 5H n= 395 308 Z I B 285 284 ZY B Encounter Method D=0.086 p>0.05 I n d i v i d u a l D i s t r i but i onJ Method X 2=l.34 p>0.05 df=l Table 18. Area I. Advance. The number of i n t e r a c t i o n s in which the advance behaviour was and was not used i s given and compared f o r c l a s s e s l i s t e d on the ord i n a t e while i n t e r -a c t i n g with c l a s s e s l i s t e d on the ab s c i s s a a b s c i s s a . ZIB ZYB ZIB Advance No Advance Frequency Of Use 18 260 11 106 X2=0.6H-p>0.05 df=1 O.O65 0.094 ZYB Advance No Advance Frequency Of Use 4 163 6 112 X2=1.67 p>0.05 df=1 0.024 0.052 65 LeBoeuf and P e t e r s o n ' s (1968) would be c o n s i d e r e d dominant The f o l l o w was not used Area I . h y p o t h e s i s (see page 3 4 ) , ZIB t o ZYB. hY 2. c a l i f o r n i a n u s c l a s s e s on INVESTIGATIVE BEHAVIOUR Zalophus c a l i f o r n i a n u s males use i n v e s t i g a t i v e b e h a v i o u r l e s s f r e q u e n t l y (Table 19) than do E. j u b a t u s males ( F i g u r e 8) . No s i g n i f i c a n t t r e n d i s o b s e r v e d f o r t h e d i r e c t i o n o f i n v e s t i g a t i v e b e h a v i o u r i n Z. c a l i f o r n i a n u s i n t e r o r i n t r a c l a s s i n t e r a c t i o n s . NON-BODY AND BODY CONTACT BEHAVIOUR The use of non-body c o n t a c t and body c o n t a c t b e h a v i o u r i s g i v e n i n T a b l e 20. ZIB use non-body c o n t a c t b e h a v i o u r r e l a t i v e l y more f r e q u e n t l y than do ZYB's i n i n t r a c l a s s i n t e r a c t i o n s . MISCELLANEOUS BEHAVIOUR (1) MOUNTING No attempted or s u c c e s s f u l mounts were o b s e r v e d f o r e i t h e r Z. c a l i f o r n i a n u s c l a s s e s . AREA H SITE DESCRIPTION Are a H ( F i g u r e 1) i s a b o u l d e r beach ( r o c k s 10-30 cm. i n diameter) w h i c h , at h i g h t i d e , i s 70 meters i n l e n g t h and 66 Table 19. Area I. Investigative Behaviour. The number of interactions in which invest igat ive behaviour was and was not used is given and.compared for classes l i s t ed on the ordinate while interact ing with classes l i s ted on the abscissa. ZIB ZYB ZIB Investigative Behaviour 14 9 No Investigative X2=0.83 Behaviour 264 108 p>0.05 df=l Frequency Of Use 0.050 0.077 ZYB Investigative Behaviour 3 8 No Investigative X2=3.30 Behaviour 164 110 p>0.05 df=1 Frequency Of Use 0.018 0.073 6 7 •Table 20. Area I. Non-body And Body Contact Behaviour. The number of non-body and body contact behaviour patterns used by the classes l i s t ed on the ordinate while interact ing with classes on the abscissa is given and compared. X2=33.53; P<0.05; df=3. ZIB ZYB ZIB Non-body Contact 310 276 Body Contact 212 _ 258 Proportion Of Non-body Contact 0.594 0.517 ZYB Non-Body Contact 413 192 Body Contact 220 281 Proportion Of Non-body Contact 0.652 0.406 68 15 meters i n width- The beach i s l o c a t e d on the s h e l t e r e d s i d e o f the i s l a n d and has a g r a d u a l s l o p e which p e r m i t s easy a c c e s s t o and from the water. O b s e r v a t i o n s were made from b l i n d s 3 and 4, from a d i s t a n c e o f 10 t o 50 meters. POPULATION STRUCTURE AND DISTRIBUTION Both E. j u b a t u s and Z. c a l i f o r n i a n u s males h a u l out on t h i s beach. The g e n e r a l p o p u l a t i o n s t r u c t u r e i s g i v e n i n T a b l e 21. On t h r e e o c c a s i o n s female E. -jubatus were observed t r y i n g t o ha u l out on Area H. I n a l l c a s e s s e v e r a l EIB and EYB i m m e d i a t e l y e x h i b i t e d an advance o r f a s t advance b e h a v i o u r p a t t e r n and t h e f e m a l e s r e t r e a t e d i n t o the ocean. E x t e n s i v e crowding i n c e r t a i n p a r t s of Area H pr e v e n t e d a c c u r a t e d e t e r m i n a t i o n of sea l i o n d i s t r i b u t i o n and a s s o c i a t i o n by age c l a s s , so t h e s e data were r e c o r d e d o n l y a t t h e s p e c i e s l e v e l . The d i s t r i b u t i o n o f a n i m a l s i s i n f l u e n c e d by the t i d e s . F i g u r e 14 (top) shows a d i s t r i b u t i o n a t h i g h t i d e . Zalophus c a l i f o r n i a n u s t e n d t o l o c a t e t h e m s e l v e s on the upper or c l i f f - s i d e o f t h e beach, w h i l e E. j u b a t u s b u l l s a r e found near the water's edge. At low t i d e the band of E. j u b a t u s a l o n g the h i g h t i d e l i n e remains somewhat i n t a c t ( F i g u r e 14, bottom). While the t i d e i s l o w , the Z. c a l i f o r n i a n u s which h a u l out remain i n t h e l a n d space between the low and h i g h t i d e marks and appear r e l u c t a n t t o c r o s s the " l i n e " of l a r g e r E. j u b a t u s . As the water r i s e s t o the h i g h t i d e l e v e l , t h e s e Z. c a l i f o r n i a n u s must move up t h e beach i f t h e y wish t o remain dry and a r e f i n a l l y j u x t a p o s e d t o the " l i n e " Table 21. Area H. Class s t r u c t u r e of sea l i o n c l a s s e s on hau l -out area. Numbers v a r i e d from 182 to 265 during observation periods. Test f o r homogeniety of proport ions: X2=21.62; p>0.05; df = 14. Class P r o p o r t i o n Of Population EOB 0.05 EIB 0.17 EYB 0.09 ZIB 0.50 ZYB 0. 19 Figure 14. Area H. D i s t r i b u t i o n of sea l i o n s on beach at high t i d e (top) and low t i d e (bottom). BE - Beach. CF - Cl i f f . WA - Water. 70 71 of E. J u s t u s males. At t h i s t i d e l e v e l many of the Z. c a l i f o r n i a n u s e i t h e r r e t u r n t o the water o r move a l o n g the beach t o f i n d an empty c o r r i d o r t h r o u g h the E. j u b a t u s . Other Z. c a l i f o r n i a n u s choose t o t r a v e l q u i c k l y over the J . j u b a t u s b u l l s t o s u i t a b l e r e s t i n g a r e a s h i g h e r on the beach. I t i s d u r i n g t h e s e sudden s p r i n t s t h a t t h e m a j o r i t y of the Z. c a l i f o r n i a n u s - E . j u b a t u s i n t e r a c t i o n s o c c u r . Zalophus c a l i f o r n i a n u s males c r o s s i n g the E. j u b a t u s b a r r i e r always m a i n t a i n the l o w - p r o f i l e s u b o r d i n a t e p o s t u r e . CLASS ASSOCIATIONS Both s p e c i e s show a tendency towards i n t r a s p e c i f i c g r o u p i n g ( F i g u r e 15). T h i s i n t r a s p e c i f i c g r o u p i n g i s a l s o e v i d e n t i n F i g u r e 16, where the number of a n i m a l s i n v o l v e d i n an i n t r a s p e c i f i c a s s o c i a t i o n i s always h i g h e r t h a n e x p e c t e d , whereas t h e number i n v o l v e d i n an i n t e r s p e c i f i c a s s o c i a t i o n i s always l o w e r than e x p e c t e d . I f an a n i m a l was observed not t o be i n p h y s i c a l c o n t a c t wit h a n o t h e r , i t was c l a s s e d as s o l i t a r y . Eumetopias j u b a t u s a r e found s o l i t a r i l y more f r e q u e n t l y than a r e Z. c a l i f o r n i a n u s ( F i g u r e 1 7 ) . I t i s a l s o e v i d e n t i n F i g u r e 17 t h a t the f r e q u e n c y of s o l i t a r y Z. c a l i f o r n i a n u s n o t i c e a b l y d e c r e a s e s d u r i n g c o o l e r weather, whereas t h i s does not happen w i t h E. j u b a t u s , Figure 15- Area H. The frequency of p h y s i c a l contact by c l a s s e s l i s t e d on the ordi n a t e with the c l a s s e s l i s t e d on the a b s c i s s a i s given. observed expected Expected frequencies are c a l c u l a t e d -using Table 21. Figure 16. Area H. A s s o c i a t i o n . The average number of i n d i v i d u a l s of the species l i s t e d on the a b s c i s s a found w i t h i n a 3 meter d i s t a n c e of i n d i v i d u a l s of the species l i s t e d on the o r d i n a t e i s given. Expected values are c a l c u l a t e d us ing Table 21. observed expected 6 - i 73 00 ZD •z. 3 CD 3 n= 4 9 8 6 - i 5 0 0 X 2=l67.4 P « = 0 . 0 5 df=1 C c o Ml n= 1 4 8 5 E. jubatus 1749 Z. c a 1 i f o r n i a n u s X 2 = 9 0 . 5 p < 0 . 0 5 df= 1 Figure 17- Area H. The proportion of E. jubatus and Z. ca1i forn i anus found s o l i t a r y on a warm sunny day (day l) and a co l d windy day (day 2) are given. Density of animals and t i d a l l e v e l s approximately equal on both days. Day 1 - about 16 degrees C. ; c l e a r sky; no wind. Day 2 - about 3 degrees C ; snowing l i g h t l y ; wind 20 to 25 knots. o ii r Z. c a l i f o r n i a n u s CL. "O X -h . N II A II — ON) • Ul O • Ul N) PERCENT u i II E. jubatus ^ ^iwnin u i I CL XI x II V || — o o o — Ul 00 75 CLASS INTERACTIONS INTERACTION DURATION AND FREQUENCY The minutes o b s e r v e d , i n t e r a c t i n g t i m e , number of i n t e r a c t i o n s and r a t e s d e r i v e d from t h e s e d a t a a r e g i v e n i n T a b l e 22. The p r o p o r t i o n of time spent i n t e r a c t i n g , i n t e r a c t i o n r a t e s and average d u r a t i o n of an i n t e r a c t i o n are l o w e r f o r 2. c a l i f o r n i a n u s c l a s s e s than those f o r E. -jubatus c l a s s e s - EOB have a s i g n i f i c a n t l y lower average i n t e r a c t i o n d u r a t i o n than do EIB and EYB. EOB from Area H and Area A (Table 2) have a h i g h e r i n t e r a c t i o n r a t e and spend a g r e a t e r p r o p o r t i o n of t h e i r time i n t e r a c t i n g than do EOB on Area B ( T a b l e 11). EIB and EYB have a h i g h e r i n t e r a c t i o n r a t e on Area H than on Area A (Table 2 ) . T h i s r e s u l t i s a l s o found f o r 2. c a l i f o r n i a n u s b u l l s on Area H as compared t o Area I (Table 17). Eumetopias j u b a t u s i n t e r a c t i n t r a s p e c i f i c a l l y f o r l o n g e r p e r i o d s of time than do 2, c a l i f o r n i a n u s ( F i g u r e 1 8 ) . There i s no s i g n i f i c a n t d i f f e r e n c e between the d u r a t i o n s of i n t e r s p e c i f i c c l a s s i n t e r a c t i o n s a l t h o u g h t h e r e i s a tendency f o r i n t e r a c t i o n s i n v o l v i n g a n i m a l s of l a r g e s t s i z e d i f f e r e n c e to be of s h o r t e s t d u r a t i o n . Za.lophus c a l i f o r n i a n u s r a r e l y p r o l o n g an i n t e r a c t i o n beyond 10 seconds and o f t e n d i s p l a y the move away b e h a v i o u r q u i c k l y when e n c o u n t e r i n g a l a r g e r a n i m a l of e i t h e r s p e c i e s . The i n t r a c l a s s i n t e r a c t i o n s of EOB i n Area H are much s h o r t e r than t h o s e f o r EOB i n Area A (see F i g u r e 3 ) . The i n t e r a c t i o n f r e q u e n c i e s of the v a r i o u s c l a s s e s are g i v e n i n F i g u r e 19. I f i n t e r a c t i o n s were random the 76 Table 22. Area H. Proportion of time spent interact ing, interact ion rate and average duration of an interact ion, plus the data for ca lcu lat ing these rates are given for each sea l ion class l i s t ed on the ordinate. Data for each class have been divided into day (D) or night (N) categories depending on the time of observation. Class M i nutes M i nutes Proport ion Numbe r 1nteract ion Average Observed• Spent Of Of Rate: Durat ion 1nteract i ng Time Spent 1 nteract ions 1 nteract i ons Of An 1nteract i ng Per Minute 1 nteract ion (Seconds) EOB D 4069 810.6 0. 199 1341 0.330 36 N 853 157.9 0. 185 245 0.287 39 EIB D 8147 * 2972.3 0.365 2859 0.351 62 N 2056 591.6 0.288 674 0.328 53 EYB D 6623 1826.5 0.276 2239 0.338 49 N 1726 564.2 0.327 513 0.297 66 ZIB D 4510 159.9 0.035 692 0.153 14 N 1512 45.5 0.030 163 0.108 17 ZYB D 1941 91.3 0.047 312 0. 161 18 N 503 21 . 1 0.042 74 0. 147 17 X2=810.5 H=lI8.3 p<0.05 p <0.05 df=9 df=9 Figure 18. Area H. Mean I n t e r a c t i n g Duration. The i n t e r a c t i o n d u r a t i o n i s given f o r the c l a s s e s l i s t e d on the o r d i n a t e while i n t e r a c t i n g with the c l a s s e s l i s t e d on the a b s c i s s a . 77 100-, EOB H lOO-i EIB H 1001 EYB H n= 328 1001 ZIB H loon ZYB H n= 9 n= 134 1058 n= 160 945 49 312 1834 602 36 63 538 702 496 19 231 312 165 •i n 10 38 24 284 1 30 EOB EIB EYB ZIB ZYB H=48.31 p <0.05 df=4 H=63.70 P<0.05 df=4 H=54.28 p <0.05 df=4 H=8.13 p>0.05 df=4 H=5.83 p >0.05 df=4 Figure 19. Area H. I n t e r a c t i o n Frequency. The frequency wit h which the c l a s s e s l i s t e d on the o r d i n a t e engaged in i n t e r a c t i o n s w i t h the c l a s s e s l i s t e d on the a b s c i s s a i s given. Expected frequencies are c a l c u l a t e d using Table 21. 78 100 - i EOB H X2=4159.3 p <0.05 df=4 100 - i EIB 1 n= 1.34 1058 100 -i 312 63 19 n X2=4055.4 p <0.05 df=4 mm Li • n= 328 1834 602 538 2 31 EYB H n= 60 loon Z\B-\ n- 9 loon Z Y BH o 100-i Expected' EOB 9^ 5 49 EIB 633 36 EYB 702 ZIB 312 165 ZYB X2=l502.6 p<0.05 df=4 X2=126.2 p <0.05 df=4 X2=63.6 p<0.05 df=4 n= 10 38 24 ; 284 130 B 1 mm Hi H i 79 f r e q u e n c i e s would approximate Table 21. I n a l l i n s t a n c e s , i n t r a s p e c i f i c i n t e r a c t i o n s a r e more common than expected w h i l e i n t e r s p e c i f i c i n t e r a c t i o n s a r e lo w e r than e x p e c t e d . Each s p e c i e s i s a n a l y z e d s e p a r a t e l y i n F i g u r e s 20 through 23. Under t h e s e c r i t e r i a , EOB i n t e r a c t more f r e q u e n t l y w i t h EIB and s l i g h t l y l e s s f r e q u e n t l y w i t h EOB and EYB than e x p e c t e d . EIB i n t e r a c t w i t h EOB as e x p e c t e d , but w i t h t h e m s e l v e s more and w i t h EYB l e s s t h a n e x p e c t e d . EYB i n t e r a c t w i t h themselves and EOB more than e x p e c t e d and with EIB as e x p e c t e d . These r e s u l t s are s i m i l a r t o those found f o r male E. j u b a t u s c l a s s e s on Area fi (see F i g u r e 4 ) . Zalophus c a l i f o r n i a n u s c l a s s e s i n t e r a c t randomly w i t h t h e i r n e i g h b o u r s i n both i n t e r s p e c i f i c and i n t r a s p e c i f i c i n t e r a c t i o n s . ACTIVITY FREQUENCY The a c t i v i t y data g i v e n i n F i g u r e 2 4 show t h a t , as i n a l l p r e v i o u s c a s e s , v a l u e s c a l c u l a t e d by the encoun t e r method a r e h i g h e r t h a n t h o s e c a l c u l a t e d by the i n d i v i d u a l d i s t r i b u t i o n method. Eumetopias j u b a t u s spend much more time a c t i v e t h a n do Z. c a l i f o r n i a n u s . EIB and EYB a r e more a c t i v e than EOB. A l l E. j u b a t u s c l a s s e s on Area H a r e more a c t i v e than the same c l a s s e s on Area A ( F i g u r e 5 ) . Zalophus c a l i f o r n i a n u s a r e more a c t i v e on Area H than on Area I , Figure 2 0 . Area H. I n t e r a c t i o n Frequency. The frequency with which the c l a s s e s l i s t e d on the o r d i n a t e engaged in i n t e r a c t i o n s with c l a s s e s l i s t e d on the a b s c i s s a i s given. Expected frequencies are c a l c u l a t e d using Table 21. observed expected PERCENT Figure 21. Area H. I n t e r a c t i o n Frequency. The frequency with which the c l a s s e s l i s t e d on the o r d i n a t e engaged in i n t e r a c t i o n s with c l a s s e s l i s t e d on the a b s c i s s a is given. Expected frequencies are c a l c u l a t e d using Table 21. observed expected 100, 8 1 EOfcH n= 1 11 : 1 1 >.v.v. 1 63 19 Xz^0.96 p>0.05 df=l 100—1 LU o E I B -n= loo-. 538 X2-U65 p >0.05 df=1 EYB 1 n = 702 ZIB §1 231 ZYB X2=3-83 p>0.05 df=1 Figure 22. Area H. I n t e r a c t i o n Frequency. The frequency wit h which the c l a s s e s l i s t e d on the ord i n a t e engaged in i n t e r a c t i o n s with c l a s s e s l i s t e d on the a b s c i s s a i s given. Expected frequencies are c a l c u l a t e d using Table 21. observed expected PERCENT M M O CT> O Ul Figure 23. Area H. I n t e r a c t i o n Frequency. The frequency wit h which the c l a s s e s l i s t e d on the o r d i n a t e engaged in i n t e r a c t i o n s w i t h c l a s s e s l i s t e d on the a b s c i s s a i s given. Expected frequencies are c a l c u l a t e d using Table 21. observed expected lOO-i 83 ZIB X2=3.02 p> 0.05 df=l n= <_> 100-1 496 ZYB H X2=2.36 p>0.05 df=1 n= Z IB ZYB Figure. 2k. Area H. A c t i v i t y Frequency. If a sea l i o n had i t s head r a i s e d i t was con-sidered a c t i v e . The proportion of time that a sea l i o n had i t s head ra i s e d w h i l e i t was being observed (encounter method) and the proportion of sea l i o n s in each c l a s s that had t h e i r heads r a i s e d during p e r i o d i c counts of the haulout area ( i n d i v i d u a l d i s t r i b u t i o n method) i s given. n= 172 253 359 386 EOB EIB Encounter Method H=32.0 p <0.05 df=4 Ind iv idual D i s t r i but ion Method X2=92.2 p <0.05 df=4 CO •Cr 85 BEGINNING AND TERMINATION BEHAVIOUR (1) INITIATION OF INTERACTIONS The advance i s used by E. j u b a t u s m a i n l y i n i n t r a s p e c i f i c i n t e r a c t i o n s and o c c a s i o n a l l y i n i n t e r s p e c i f i c i n t e r a c t i o n (Table 2 3 ) . Zalophas c a l i f o r n i a n u s r a r e l y use the advance and u s u a l l y d i r e c t i t , when used, i n t r a s p e c i f i c a l l y . The younger E. j u b a t u s age c l a s s e s d i r e c t t h e advance a t o l d e r age c l a s s e s more f r e q u e n t l y on Area H than t h e y do on Area A (see F i g u r e 6 ) . The f a s t advance i s used p r i m a r i l y by E. j u b a t u s d u r i n g i n t r a s p e c i f i c i n t e r a c t i o n s (Table 2 4 ) . T h i s b e h a v i o u r was a l s o d i r e c t e d f r e g u e n t l y a t Z. c a l i f o r n i a n u s by EYB but r a r e l y by EOB o r EIB. The f i v e r e c o r d e d i n s t a n c e s where Z. c a l i f o r n i a n u s used the f a s t advance took p l a c e a f t e r b oth s p e c i e s had been on t h e i s l a n d f o r s e v e r a l months and were d i r e c t e d a t s m a l l EYB o n l y . (2) INTENTIONAL INITIATION AND DOMINANCE RELATIONSHIPS The number o f i n t e r a c t i o n s i n t e n t i o n a l l y i n i t i a t e d by each c l a s s d u r i n g i n t e r c l a s s i n t e r a c t i o n s i s g i v e n i n Table 25. A p p l i c a t i o n o f H a r e s t a d ' s (1973) h y p o t h e s i s t h a t dominants i n i t i a t e more i n t e r a c t i o n s than s u b o r d i n a t e s , shows t h a t a l l c l a s s e s of E. j u b a t u s a r e dominant t o a l l c l a s s e s of Z. c a l i f o r n i a n u s , EOB a r e dominant t o a l l c l a s s e s and EIB are s u b o r d i n a t e o n l y t o EOB. ZIB a r e dominant t o ZYB. 86 Table 23. Area H. Advance. The number of interactions in which the advance was used and was not used is given and compared for the classes l i s ted on the ordinate while interact ing with classes l i s t ed on the abscissa. EOB EOB Advance 35 . No Advance' 99 Frequency Of Use 0.261 EIB Advance 459 No Advance 927 Frequency Of Use 0.331 EYB Advance 55 No Advance 417 Frequency Of Use 0.117 ZIB Advance 0 No Advance 72 Frequency Of Use 0.000 ZYB Advance 0 No Advance 29 Frequency Of Use 0.000 EIB EYB ZIB ZYB 514 91 3 1 872 381 69 29 X2=62.69 p<0.05 0.371 0.193 0.042 0.034 df=4 763 6 l 3 47 44 1071 934 484 281 x2=i83.1 p<0.05 0.416 0.396 0.088 0. 135 df=4 330 255 89 31 1217 378 649 305 X2=187.6 p<0.05 0.213 0.403 0.121 0.092 df=4 6 13 72 69 525 725 431 373 x2=i50.0 p<0.05 0.01 1 0.018 0. 143 0.156 df=4 0 2 17 18 325 334 425 112 X2=67.63 P<0.05 0.000 0.001 0.038 0.138 df=4 87 Table 24. Area H. Fast Advance. The number of interact ions in whi ich the fast advance was and was not used is give and compared for the classes 1i sted on the ord i nate wh i le interact ing with the classes 1i sted on the absc i ssa. *sample s ize too sma11 for analys is . EOB EIB EYB ZIB ZYB EOB Fast Advance 23 190 40 0 1 No Fast Advance 111 1196 432 72 28 Xz=22.3 p <0.05 Frequency Of Use 0. 172 0.137 0.085 0.000 0.034 df=4 EIB Fast Advance' 130 237 159 15 13 ..2 , • No Fast Advance 1256 1597 1388 516 312 ' X =55.6 p<0.05 Frequency Of Use 0.094 0.129 0.103 0.028 0.040 df=4 EYB Fast Advance 6 49 84 95 27 No Fast Advance 466 1498 549 643 309 X^=126.6 p<0.05 Frequency Of Use 0.013 0.032 0.133 0.129 0.080 df=4 ZIB Fast Advance 0 0 2 0 0 No Fast Advance 72 531 736 1006 442 Frequency Of Use 0.000 0.000 0.003 0.000 0.000 ZYB Fast Advance 0 0 3 0 0 No Fast Advance 29 325 333 442 260 J U Frequency Of Use 0.000 0.000 0.010 0.000 0.000 Table 25- Area H. Int e n t i o n a l I n i t i a t i o n . I n t e n t i o n a l i n i t i a t i o n of i n t e r a c t i o n s using the advance and f a s t advance behaviour patterns. " R a t i o " i s the number of i n t e r a c t i o n s i n t e n t i o n a l l y i n i t i a t e d by the c l a s s l i s t e d on the or d i n a t e over those i n i t i a t e d by the c l a s s l i s t e d on the a b s c i s s a w h i l e the two c l a s s e s were i n t e r a c t i n g . EIB EYB ZIB ZYB EOB 70 V 589 131/61 3/0 2/0 EIB 772/379 62/6 57/0 EYB 18 V 1 5 58/5 ZIB 69/17 89 (3') MOVE AWAY AND DOMINANCE RELATIONSHIPS T a b l e 26 compares the use of move away by the v a r i o u s c l a s s e s . The c o n c l u s i o n s from t h i s t a b l e w i t h r e s p e c t to dominance, a r e s i m i l a r t o t h o s e found e a r l i e r f o r i n t e n t i o n a l i n i t i a t i o n o f i n t e r a c t i o n s (Table 2 5). F i g u r e 25 l i s t s t he c l a s s e s a c c o r d i n g t o the dominance r e l a t i o n s h i p d etermined by the move away and i n t e n t i o n a l i n i t i a t i o n b e h a v i o u r p a t t e r n s . T h i s i s t h e same h i e r a r c h y arrangement determined f o r E. j u b a t u s males on Area A ( F i g u r e 7) and f o r Z. c a l i f o r n i a n u s males on Area I . (4) FOLLOW The use of f o l l o w b e h a v i o u r i s g i v e n i n T a b l e 27. T h i s b e h a v i o u r p a t t e r n i s not used by Z. c a l i f o r n i a n u s . I t i s used by E. j u b a t u s p r i m a r i l y d u r i n g i n t e r a c t i o n s w i t h peer c l a s s e s and s l i g h t l y s u b o r d i n a t e c l a s s e s . INVESTIGATIVE BEHAVIOUR The p r o p o r t i o n o f i n t e r a c t i o n s i n v o l v i n g i n v e s t i g a t i v e b e h a v i o u r f o r each c l a s s i s shown i n F i g u r e 26. As found i n ar e a s A and B, EOB do not use i n v e s t i g a t i v e b e h a v i o u r d u r i n g i n t r a c l a s s i n t e r a c t i o n s . L a r g e E. j u b a t u s males o c c a s i o n a l l y use i n v e s t i g a t i v e b e h a v i o u r when i n t e r a c t i n g w i t h s m a l l e r sea l i o n s . Eumetopias j u b a t u s i n t e r a c t i o n s w i t h Z. c a l i f o r n i a n u s a r e g e n e r a l l y t o o s h o r t t o permit i n v e s t i g a t i v e b e h a v i o u r because Z. c a l i f o r n i a n u s males promptly move away a f t e r t he i n t e r a c t i o n b e g i n s . I f an E. ju b a t u s male approaches a Z. c a l i f o r n i a n u s male t h a t i s s l e e p i n g however, t h e i n t e r a c t i o n o f t e n b e g i n s w i t h the E. Table 26. Area H. Move Away. Determination of h i e r a r c h y using move away. The " r a t i o " i s the number of i n t e r a c t i o n s where move away was used by the c l a s s l i s t e d on the or d i n a t e over the number of times that i t was used by the c l a s s l i s t e d on the a b s c i s s a while the two c l a s s e s were i n t e r a c t i n g . EIB EYB ZIB ZYB EOB 51/646 4/339 6/55 0/24 EIB 287/687 42/388 0/292 EYB 71/335 8/202 ZIB 49/84 Figure 25. Area H. Dominance hi e r a r c h y f o r c l a s s e s as e s t a b l i s h e d by i n t e n t i o n a l i n i t i a t i o n and move away behaviour patterns. 9 7 EOB EIB EYB ZIB ZYB Dominant Subord i nant 92 Table 27. Area H. Follow. Use of f o l l o w by c l a s s e s l i s t e d on the ord i n a t e w h i l e i n t e r a c t i n g w i t h c l a s s e s l i s t e d on the a b s c i s s a . Number of times that the partner on the a b s c i s s a moved away from the partner on the or d i n a t e and the number of times that the partner on the or d i n a t e sub-sequently followed are given. EOB EIB EYB ZIB ZYB EOB Fol1 ow 36 317 86 3 6 0 Move Away x =331.3 62 646 339 55 24 p<0.05 df=4 Frequency Of Use 0.581 0.491 0.254 0.055 0.250 EIB Fol1ow 3 351 391 68 31 X 2=187.9 Move Away 51 970 687 388 292 p< 0.05 df=4 Frequency Of Use 0.059 0.362 0.569 0.175 0. 106 EYB Fol1ow 0 52 94 26 29 X2=65.0 Move Away 4 284 267 335 202 p< 0.05 df=4 Frequency Of Use 0.000 0.183 0.352 O.O78 0.144 Figure 26. Area H. I n v e s t i g a t i v e Behaviour. The percentage of i n t e r a c t i o n s during which c l a s s e s l i s t e d on the o r d i n a t e used i n v e s t i g a t i v e behaviour while i n t e r -a c t i n g with c l a s s e s l i s t e d on the a b s c i s s a i s given. "sample s i z e too small for a n a l y s i s . 9 3 20n EOB 2 0 n EIB H 20-i o of EYB n= 20-i ZIB n= 9 20-1 ZYB H n= 134 1058 3 1 2 n= 328 1834 ' 6 3 n 4 8 2 287 60 9 45 6 3 3 702 312 4 9 3 6 503 158 0 0 y u 1 0 3 8 24 2 84 130 EOB EIB EYB ZIB ZYB X2=40.8 p<0.05 df=4 X 2 = 7 1 . 8 P « = 0 . 0 5 df= 4 X 2 = 5 2 . 4 P < 0 . 0 5 df= 4 94 j u b a t u s p a r t n e r d i r e c t i n g n o s i n g B ( p l a c i n g t h e nose on or near the p e r i a n a l r e g i o n ) a t t h e Z. c a l i f o r n i a n u s p a r t n e r . Zalophus c a l i f o r n i a n u s males r a r e l y used i n v e s t i g a t i v e b e h a v i o u r . When i n v e s t i g a t i v e b e h a v i o u r i s used by ZIB or ZYB i t i s d i r e c t e d most f r e q u e n t l y a t EYB. The t y p e s o f i n v e s t i g a t i v e b e h a v i o u r p a t t e r n s used by each c l a s s a r e g i v e n i n F i g u r e 27. D u r i n g t h i s s t u d y , o l d e r sea l i o n s o f each s p e c i e s used fewer t y p e s o f i n v e s t i g a t i v e b e h a v i o u r p a t t e r n s t h a n d i d younger sea l i o n s of t h a t s p e c i e s . NON-BODY AND BODY CONTACT BEHAVIOUR Non-body c o n t a c t b e h a v i o u r was used e x t e n s i v e l y i n i n t e r s p e c i f i c i n t e r a c t i o n s (Table 2 8 ) . Most of t h e s e i n t e r a c t i o n s were o f s h o r t d u r a t i o n (see F i g u r e 18) and o f t e n both p a r t i e s use t h e mouth b e h a v i o u r p a t t e r n . I n i n t e r s p e c i f i c i n t e r a c t i o n s the Z. c a l i f o r n i a n u s p a r t n e r would u s u a l l y move away. Body c o n t a c t b e h a v i o u r i s g e n e r a l l y used i n prolonged i n t e r a c t i o n s where n e i t h e r p a r t n e r moves away. T h i s was r a r e l y observed i n i n t e r s p e c i f i c i n t e r a c t i o n s . The t h r e e "neck d i s p l a y " non-body c o n t a c t b e h a v i o u r p a t t e r n s ( s n o b b i n g , f u l l neck and t u r n away) s e r e never used d u r i n g i n t e r s p e c i f i c i n t e r a c t i o n s . I n t e r s p e c i f i c i n t e r a c t i o n s i n v o l v e d non-body c o n t a c t b e h a v i o u r p a t t e r n s of mouth (by both s p e c i e s ) , nodding (E. j u b a t u s o n l y ) and neck waving (Z. c a l i f o r n i a n u s o n l y ) . These p a t t e r n s appear t o be t h e t h r e e most p h y s i c a l l y a g g r e s s i v e of the non-body c o n t a c t p a t t e r n s . EOB use p r e d o m i n a n t l y non-body c o n t a c t b e h a v i o u r when Figure 27. Area H. I n v e s t i g a t i v e Behaviour. The types of i n v e s t i g a t i v e behaviour patterns used by the c l a s s e s l i s t e d on the a b s c i s s a are given. 95 EOB EIB EYB ZIB ZYB 1 nvest i gat i ve Behav i our Nosing B Nosing B Nos i ng A Nosing B Nosing A Pattern Observed Nosing C Nos i ng B Nosing B L i c k i n g B Nos i ng C Nosing C L i c k i n g A L i c k i n g B 96 Table 28. Area H. Non-body Contact And Body Contact. Use of non-body and body contact behaviour patterns by classes l i s t ed on the ordinate whi1e interact ing with classes l i s t ed on the ab-scissa. The number of non-body and body contact behaviour used i s g iven. X2=5369-7; P<0.05; df=24. EOB EIB EYB ZIB ZYB. EOB Non-body Contact 1069 6451 954 94 46 Body Contact 1018 9878 2192 26 23 Proportion Of Non-body Contact 0.512 0.395 0.303 0.783 O.667 EIB Non-body Contact 1658 10279 1803 1912 725 Body Contact 3929 25676 7242 621 227 Proportion Of Non-body Contact 0.297 0.286 0. 199 0.755 0.762 EYB Non-body Contact 489 1744 1898 1363 352 Body Contact 1006 8799 12063 807 147 Proportion Of Non-body Contact 0.327 0.165 0.136 O.628 0.705 ZIB Non-body Contact 24 67 53 • 522 I83 Body Contact 3" 24 21 479 206 Proportion Of Non-body Contact 0.889 0.736 0.716 0.521 0.470 ZYB Non-body Contact 32 56 59 537 336 Body Contact 9 19 15 312 348 Proportion Of Non-body Contact 0.821 0.747 0.797 O.633 0.491 97 i n t e r a c t i n g w i t h o t h e r EOB but use i n c r e a s i n g amounts of body c o n t a c t b e h a v i o u r when i n t e r a c t i n g w i t h younger E. J u s t u s c l a s s e s . EYB use p r e d o m i n a n t l y body c o n t a c t b e h a v i o u r when i n t e r a c t i n g w i t h o t h e r EYB but use i n c r e a s i n g amounts o f non^body c o n t a c t when i n t e r a c t i n g w i t h o l d e r a n i m a l s . These r e s u l t s a r e s i m i l a r t o t h o s e found f o r male !• j u b a t u s c l a s s e s on Area A (Table 9 ) . MISCELLANEOUS BEHAVIOUR (1) MOUNTING S e v e r a l attempted and s u c c e s s f u l mounts were observed f o r EIB and EYB (Table 29) but none were observed f o r EOB, ZIB o r ZYB. The d a t a f o r T a b l e 29 were c o l l e c t e d from g e n e r a l o b s e r v a t i o n s . EIB were a p p a r e n t l y more s u c c e s s f u l a t mounting Z. c a l i f o r n i a n u s b u l l s t h a n E. j u b a t u s b u l l s . On s e v e r a l o c c a s i o n s EIB were observed mounting s l e e p i n g Z. c a l i f o r n i a n u s b u l l s and then commencing p e l v i c movements f o r s e v e r a l seconds b e f o r e the Z. c a l i f o r n i a n u s male would wake up and respond by a t t e m p t i n g t o move away. (2) SHIVERING Animals r e s t i n g near t h e water's edge a r e o f t e n kept wet by the a c t i o n of the waves and/or wind d r i v e n s p r a y . As shown i n F i g u r e 14 t h e s e a r e g e n e r a l l y E. j u b a t u s . I t was observed t h a t wet Z. c a l i f o r n i a n u s , when exposed t o c h i l l i n g winds, d i s p l a y e d a b e h a v i o u r c o n s p i c u o u s l y r e s e m b l i n g s h i v e r i n g , w h i l e E. j u b a t u s d i d n o t . S o l i t a r y Z. c a l i f o r n i a n u s appeared t o s h i v e r more f r e q u e n t l y than those i n c o n t a c t w i t h o t h e r a n i m a l s . A l s o t h e m a j o r i t y of t h e Table 29. Area H. Mounts. Number of attempted and s u c c e s s f u l mounts is given f o r c l a s s e s l i s t e d on the ordi n a t e which d i r e c t e d the behaviour at c l a s s e s l i s t e d on the a b s c i s s a . EIB EYB ZIB ZYB EIB Attempted Mounts 8 14 11 7 Mounts 0 3 8 5 EYB Attempted Mounts Mounts 0 2 5 7 0 0 0 2 99 s h i v e r i n g a n i m a l s seemed t o be o f the s m a l l e r s i z e range. T h i s was not q u a n t i f i e d . INTERACTION DESCRIPTIONS INTRASPECIFIC - E. j u b a t u s P r o l o n g e d i n t e r a c t i o n s {longer than 30 seconds) were o f t e n o b s e r v e d f o r E- j u b a t u s p a r t n e r s but r a r e l y f o r Z. c a l i f o r n i a n u s p a r t n e r s . The b e h a v i o u r p a t t e r n s and s t r a t e g i e s i n v o l v e d i n t h e s e i n t r a s p e c i f i c e n c o u n t e r s a l s o d i f f e r e d . A t y p i c a l i n t e r a c t i o n between two EIB would p r o g r e s s as f o l l o w s : Sea l i o n A approaches sea l i o n B w i t h a f a s t advance. B t u r n s t o f a c e A and b o t h engage i n n e c k i n g C. A f e i n t s t o the r i g h t then q u i c k l y l u n g e s to t h e l e f t f o r the r i g h t f o r e f l i p p e r o f B. B q u i c k l y swings t o i t s l e f t drawing i t s r i g h t f l i p p e r out o f the range of A, w h i l e i t i s l u n g i n g a t A*s r i g h t f o r e f l i p p e r . A, meanwhile, having missed B's f l i p p e r pushes t o i t s r i g h t w h i l e b i t i n g at B*s neck, t r y i n g t o knock B o f f b a l a n c e . B, however, has a h o l d on A*s r i g h t f l i p p e r and, w i t h A g r i p p i n g t i g h t l y t o B*s neck, t h e two move around i n a c i r c l e f o r s e v e r a l seconds u n t i l t h ey break a p a r t . Both d i s p l a y c r o s s mouthing f o r a few seconds and then the l u n g i n g and p u s h i n g b e g i n s a g a i n -O c c a s i o n a l l y when both p a r t n e r s break a p a r t , one {A) w i l l move back and d i s p l a y t h e t u r n away b e h a v i o u r p a t t e r n . I f A has m a i n t a i n e d the upper hand t o t h i s p o i n t , B r a r e l y c o n t i n u e s l u n g i n g but w i l l e i t h e r d i s p l a y the t u r n away o r . 100 mere o f t e n , w i l l move away away as B r e t r e a t s , A w i l l b r e a k s and r u n s d u r i n g a 1 a few meters. A w i l l t h e n f u l l neck or t u r n away. V o c a l i z a t i o n d u r i n g r e s t r i c t e d t o i n t e r m i t t e n t from A. I f A i s d i s p l a y i n g t u r n r a r e l y f o l l o w B. I f , however, B ngin g match A u s u a l l y f o l l o w s f o r s t o p and d i s p l a y e i t h e r s n o b b i n g , t h e i n t e r a c t i o n i s g e n e r a l l y g r u n t s , coughs o r wheezes. INTRASPECIFIC - Z. c a l i f o r n i a n u s Zalophus c a l i f o r n i a n u s i n t r a s p e c i f i c i n t e r a c t i o n s do not c o n t a i n the o v e r t l y a g g r e s s i v e b e h a v i o u r of E. j u b a t u s i n t r a s p e c i f i c i n t e r a c t i o n s . A j o u s t i n g match, which as mentioned above i s r a r e , would p r o g r e s s as f o l l o w s : A advances towards B w i t h i t s head waving from s i d e t o s i d e and v o c a l i z i n g l o u d l y w i t h t h e c h a r a c t e r i s t i c Z. c a l i f o r n i a n u s bark. B t u r n s i t s body to f a c e A but d i s p l a y s t u r n away and s n o b b i n g ( o b l i g u e s t a r e of P e t e r s o n and Bartholomew, 1967) wi t h eyes open and d i r e c t e d at A and s t a r t s v o c a l i z i n g . A c o n t i n u e s towards B u n t i l t h e necks of both a n i m a l s a r e t o u c h i n g , whereupon b c t h p a r t n e r s s t a r t p u s h i n g v i g o r o u s l y w i t h neck and c h e s t . Both a n i m a l s h o l d t h e i r heads h i g h , waving them back and f o r t h r a p i d l y and v o c a l i z i n g l o u d l y . O c c a s i o n a l l y the a n i m a l s l o s e t h e i r b a l a n c e and s l i p o f f to the s i d e of the opponent. T h i s does not appear t o be i n t e n t i o n a l or r e p r e s e n t a lun g e by one of the a n i m a l s . Both p a r t n e r s i m m e d i a t e l y move back about 1/2 meter and d i s p l a y t u r n away b e h a v i o u r f o r s e v e r a l seconds u n t i l one a n i m a l r e i n i t i a t e s t h e p u s h i n g . 101 E v e n t u a l l y one o f t h e p a r t n e r s breaks and, w i t h head and body lowered i n the s u b m i s s i v e p o s i t i o n , moves away from the o t h e r - The d e f e a t e d a n i m a l ceases v o c a l i z i n g as scon as i t s t a r t s t o move away. The v i c t o r c o n t i n u e s v o c a l i z i n g and u s u a l l y does not f o l l o w t h e l o s e r , but r a t h e r goes i n t o a f u l l neck d i s p l a y , h o l d i n g t h e head up and back. S i m i l a r r e s u l t s t o t h i s l a t t e r se.gue.nce were observed by Schusterraan ( 1 9 6 8 ) . In a l l cases o b s e r v e d i t appeared to be the p a r t n e r w i t h t h e g r e a t e s t h e i g h t advantage { i . e . u s u a l l y the l a r g e r animal) t h a t won. None of the i n t r a s p e c i f i c Z. c a l i f o r n i a n u s i n t e r a c t i o n s o b served on l a n d i n v o l v e d b i t i n g (see O r r , 1965). S e v e r a l i n t e r a c t i o n s were p a r t i a l l y observed i n the water. I n t h i s t h r e e d i m e n s i o n a l e n v i r o n m e n t , t h e a n i m a l s were e x t r e m e l y a g i l e and were seen c o n t i n u o u s l y n i p p i n g a t t h e f o r e and h i n d f l i p p e r s c f the opponent. The f r e g u e n c y of j o u s t i n g matches by Z. c a l i f o r n i a n u s i n t h e water was much h i g h e r t h a n on l a n d . U n f o r t u n a t e l y t h e . r a p i d i t y of motion and r e s t r i c t e d v i s i b i l i t y made g u a n t i f i c a t i o n o f t h e s e i n t e r a c t i o n s i m p o s s i b l e . I t s h o u l d be noted however, t h a t , whereas t h e m a j o r i t y of observed p r o l o n g e d Z. c a l i f o r n i a n u s i n t e r a c t i o n s took p l a c e i n water up t o s e v e r a l meters deep, the E. j u b a t u s i n t e r a c t i o n s were g e n e r a l l y on l a n d o r i n l e s s t h a n one meter of water. 102 INTERSPECIFIC - E. j u b a t u s and Z. c a l i f o r n i a n u s I n t e r s p e c i f i c j o u s t i n g matches were g e n e r a l l y of s h o r t d u r a t i o n . A l l were i n i t i a t e d by E. j u b a t u s b u l l s . Both p a r t n e r s would attempt f o l l o w i n g t h e b e h a v i o u r a l sequences t h a t would be used i n t r a s p e c i f i c a l l y - A t y p i c a l i n t e r s p e c i f i c j o u s t i n g match would p r o g r e s s as f o l l o w s : An EIB (E) advances towards a ZIB (Z) . Z t u r n s t o f a c e E and h o l d s i t s head high w h i l e neck waving and v o c a l i z i n g l o u d l y . T h i s c o m p l e t e l y exposes t h e f r o n t f l i p p e r s and lower neck of Z, and i t i s towards t h e s e t h a t E d i r e c t s a r a t h e r a g g r e s s i v e a t t a c k . While E l u n g e s a t the l o w e r p o r t i o n of Z , t h e l a t t e r a ttempts t o push a g a i n s t and hence c l i m b onto E; thu s e x p o s i n g h i m s e l f even more. W i t h i n a few seconds E can i n f l i c t s e v e r a l n o t i c e a b l e wounds and Z begins a c o n f u s e d r e t r e a t s t i l l s h a k i n g h i s head v i o l e n t l y and v o c a l i z i n g l o u d l y . I f E f o l l o w s , he does so w i t h an e x a g g e r a t e d s h u f f l e as d e s c r i b e d by Gentry (1970), nodding the head. O c c a s i o n a l l y an EIB w i l l c o r n e r a much s m a l l e r Z. c a l i f o r n i a n u s male a g a i n s t a c l i f f . A f t e r one such e n c o u n t e r , which l a s t e d s e v e r a l m i n u t e s , the s m a l l e r animal was observed b l e e d i n g from the f o r e f l i p p e r - n e c k a r e a . I t f i n a l l y escaped by c l i m b i n g d i r e c t l y over t h e EIB and r u n n i n g f o r the water. The EIB f o l l o w e d to the water's edge, c o n t i n u a l l y t r y i n g t o "head o f f " t h e Z. c a l i f o r n i a n u s male. Only d u r i n g two i n t e r s p e c i f i c s p a r i n g matches was i t observed t h a t Z. c a l i f g r n i a n u s b u l l s s t o o d t h e i r ground. 103 D a r i n g both o f these t h e p a r t n e r s were o f s i m i l a r s i z e and the ZIB adopted the l u n g i n g and f e i n t i n g p a t t e r n c h a r a c t e r i s t i c of E. j u b a t u s . These i n t e r a c t i o n s took p l a c e i n e a r l y f l a r c h , a f t e r the two s p e c i e s had o c c u p i e d t h e i s l a n d f o r s e v e r a l months. The above d e s c r i p t i o n s of i n t e r s p e c i f i c i n t e r a c t i o n s are r e s t r i c t e d t o l a n d e n c o u n t e r s . In an a q u a t i c medium Z. c a l i f o r n i a n u s b u l l s appear much b e t t e r equipped t o j o u s t w i t h E. j u b a t u s b u l l s . I n t e r s p e c i f i c i n t e r a c t i o n s l a s t i n g s e v e r a l minutes were observed i n water a p p r o x i m a t e l y 3 t o 4 meters deep. The a n i m a l s c o n t i n u a l l y t w i s t e d around each o t h e r d o i n g c i r c l e s o r f i g u r e - e i g h t s , p u shing and n i p p i n g a t each o t h e r . The prime o b j e c t of such e n c o u n t e r s appeared t o p o s i t i o n one's s e l f on t h e back of the opponent. The v i c t o r of such i n t e r a c t i o n s was i m p o s s i b l e t o determine. 104 DISCUSSION This discussion w i l l consider the results of int e r and i n t r a s p e c i f i c behaviour and address them to the h i e r a r c h i a l relationships and d i s t r i b u t i o n of sea l i o n classes on the island. These findings w i l l also be related to the learning processes and reproductive strategies of E. jubatus and Z. cal i f o r n i a n u s . I do not systematically discuss each behaviour pattern i n d i v i d u a l l y . This has been done e f f e c t i v e l y by Harestad (1973). I believe that the behaviour patterns are important to the sea l i o n s in an inte r r e l a t e d sense and, therefore, I analyze the implications of my results i n a discussion b u i l t around generalized factors that are a product of the expression of the behaviour patterns. For example, the animals are not randomly distributed around the is l a n d or on the various haulout s i t e s . In order to discuss e f f e c t i v e l y the d i s t r i b u t i o n , many facets of inter and i n t r a s p e c i f i c behaviour must be evaluated. Thus i t hoped that by discussing the behaviour patterns i n an int e r r e l a t e d context, i . e . how they affect and determine hierarchy, d i s t r i b u t i o n , etc., a r e a l i s t i c picture of sea li o n behaviour can be presented-HIERAHCHY There i s an hier a r c h i c a l r e l a t i o n s h i p among sea l i o n classes on Folger Island. The peck-dominance order (Allee, 1951) i s generally size-age related with larger-older 105 animals dominant to s m a l l e r - y o u n g e r ones. Male E. j u b a t u s are dominant t o female E. j u b a t u s and male Z. c a l i f o r n i a n u s . No comparison i s a v a i l a b l e f o r E. JMMiiJs f e m a l e s and Z. c a l i f o r n i a n u s c l a s s e s s i n c e t h e i r h a u l o u t areas do not o v e r l a p . A l t h o u g h dominance i s a term used i n an i n t e r and i n t r a s e x u a l c o n t e x t , i t s d e f i n i t i o n cannot remain f i x e d . I n a male-male i n t e r a c t i o n the dominant p a r t n e r i s t h e one t h a t i s a b l e t o d i s p l a c e the o t h e r . T h i s may be done by p h y s i c a l combat o r a g g r e s s i v e d i s p l a y s . In t h i s s t u d y i n t e n t i o n a l i n i t i a t i o n o f an i n t e r a c t i o n and move away a r e used t o d e t e r m i n e dominance r e l a t i o n s h i p s . I b e l i e v e t h a t move away r e p r e s e n t s the b e t t e r c r i t e r i o n , s i n c e i t demonstrates t h a t one p a r t n e r , the s u b o r d i n a t e , wishes t o t e r m i n a t e t h e i n t e r a c t i o n , t h u s d e c l a r i n g t h a t t h e v i c t o r has d i s p l a c e d t h e l o s e r and i s dominant. I n i t i a t i n g an i n t e r a c t i o n may r e p r e s e n t a c h a l l e n g e of dominance by a s u b o r d i n a t e , and the e x p a n s i o n of i t s b e h a v i o u r a l r e p e r t o i r e by i n t e r a c t i n g w i t h an o l d e r a n i m a l . During b r e e d i n g t e r r i t o r i a l s k i r m i s h e s i t i s t h e i n t r u d e r t h a t g e n e r a l l y i n i t i a t e s the i n t e r a c t i o n b u t he r a r e l y a c g u i r e s the t e r r i t o r y . The e s t a b l i s h m e n t o f a dominance h i e r a r c h y among male c l a s s e s has i m p l i c a t i o n s t o energy c o n s e r v a t i o n by males when they a r e on the b r e e d i n g r o o k e r y - When a b u l l a c g u i r e s a t e r r i t o r y a t a b r e e d i n g r o o k e r y , and hence e s t a b l i s h e s h i s dominance, o t h e r males r e c o g n i z e t h i s dominance w i t h minimum p h y s i c a l communication. Thus l e s s energy i s r e q u i r e d by t h e t e r r i t o r y h o l d e r f o r t h e maintenance of t h a t t e r r i t o r y . P r e v i o u s workers have found t h a t t e r r i t o r i a l b u l l s may f i g h t 106 aggressively during establishment of t e r r i t o r y boundaries, but boundary displays, which u t i l i z e much less energy than physical f i g h t i n g , are used to "defend" the t e r r i t o r i a l boundaries once they have been established (Orr and Poulter, 1967; Peterson and Bartholomew, 1967: Sandegren, 1970; Gentry, 1970). Inside his own t e r r i t o r y each b u l l i s dominant to a l l of his neighbours (Bartholomew, 1953). I t i s reasonable that the various behavioural sequences used for establishment and maintenance of dominance should be learned i n a non-breeding s i t u a t i o n , where energy conservation i s not as c r i t i c a l as on the breeding rookery-LEAHNING A s o c i a l i n t e r a c t i o n must be considered as to what both partners can gain or lose from i t . In male-male encounters, i t i s a behavioural repertoire which r e s u l t s i n the establishment of reproductive status that i s being learned and practiced. In male-female interactions, males may, in some cases, regard the females in the same context as other males, or may be establishing a conditioning process that w i l l develop into the behavioural sequences that can be used successfully by males towards females while on the breeding rookery. A discussion of physical dominance i s obviously i n v a l i d for use in the l a t t e r context. EYB, which are not sexually mature, show l i t t l e sexual interest i n the females, but rather, i n t e r a c t with them as i f they were other young b u l l s . EIB, which are sexually mature, are often seen nosing the perianal region of females 107 and t r y i n g t o mount them. They a l s o t r y to herd f e m a l e s . S i m i l a r female harassment by s u f c - a d u l t males i s r e p o r t e d f o r M- J u s t u s (Gentry, 1970, H a r e s t a d , 1973), C a l l o r i n u s u r s i n u s (Bartholomew, 1953), fiirounga l e o n i n a ( C a r r i c k et a l . 1962a, b) and M. a u g u s t i r c s t u s (LeBeouf, 1974). The b e h a v i o u r a r e performed a g g r e s s i v e l y by t h e s u b - a d u l t b u l l s and o f t e n r e s u l t i n the w i t h d r a w a l of the f e m a l e . EOB, however, do not a c t a g g r e s s i v e l y towards females and o f t e n defend them from EIB harassment. as a r e s u l t f e m a l e s tend t o crowd around EOB. Thus as males mature t h e y l e a r n t h a t harassment o f f e m a l e s causes f e m a l e s t o move away. Those EOB t h a t had the g r e a t e s t p r o p o r t i o n o f females around t h e m s e l v e s a c t i v e l y chased EIB away from f e m a l e s . T h i s may not be of p a r t i c u l a r i m p o r t a n c e d u r i n g t h e non-b r e e d i n g w i n t e r s e a s o n , but i s perhaps p a r t o f t h e l e a r n i n g -c o n d i t i o n i n g p r o c e s s t h a t w i l l be advantageous on the b r e e d i n g r o o k e r y . M i m i c k i n g was o b s e r v e d t o p l a y an i m p o r t a n t r o l e i n l e a r n i n g . EOB use p r e d o m i n a n t l y non-body c o n t a c t b e h a v i o u r d u r i n g i n t r a c l a s s i n t e r a c t i o n s . EYB use p r e d o m i n a n t l y body c o n t a c t b e h a v i o u r d u r i n g i n t r a c l a s s i n t e r a c t i o n s , but use i n c r e a s i n g amounts o f non-body c o n t a c t behaviour when i n t e r a c t i n g w i t h EIB, and an even g r e a t e r p r o p o r t i o n of non-body c o n t a c t b e h a v i o u r w i t h EOB. Often i f an EOB and an EYB a r e i n t e r a c t i n g and the EOB shows a non-body c o n t a c t d i s p l a y , the EYB w i l l attempt to copy the o l d e r a n i m a l . a l t h o u g h t h e s e attempts do not u s u a l l y conform e x a c t l y t o t h e s t e r e o t y p i c p a t t e r n of the EOB, they a r e d e f i n i t l y a t t e m p t s a t s u c h . These non-body 108 c o n t a c t d i s p l a y s a r e r a r e l y performed by EYB 1s d u r i n g i n t r a c l a s s i n t e r a c t i o n s - Body c o n t a c t p a t t e r n s a r e o n l y used d u r i n g i n t e r a c t i o n s of a d u r a t i o n l o n g enough t o permit p h y s i c a l c o n t a c t . I f an E. j u b a t u s male approaches a Z. c a l i f o r n i a n u s male w i t h a g g r e s s i v e i n t e n t { i . e . w i t h an advance or f a s t advance) o r d i r e c t s the mouth p a t t e r n a t a Z. c a l i f o r n i a n u s male, t h e l a t t e r p a r t n e r u s u a l l y moves away hence t e r m i n a t i n g the i n t e r a c t i o n b e f o r e p h y s i c a l c o n t a c t can t a k e p l a c e . Zalophus c a l i f o r n i a n u s males a p p a r e n t l y r e c o g n i z e t h e E. j u b a t u s males as b e i n g p h y s i c a l l y dominant and t h e r e f o r e a v o i d prolonged i n t e r a c t i o n s i n which th e Z. c a l i f o r n i a n u s p a r t n e r may be p h y s i c a l l y damaged. Thus I do not f e e l t h a t t h e low f r e q u e n c y of body c o n t a c t b e h a v i o u r observed d u r i n g i n t e r s p e c i f i c i n t e r a c t i o n s can be i n t e r p r e t e d as r e p r e s e n t i n g a h i g h l e v e l o f communication between the two p a r t n e r s as can be done f o r t h e same r e s u l t s d u r i n g i n t r a s p e c i f i c i n t e r a c t i o n s o f o l d e r age c l a s s e s . EOB use p r e d o m i n a n t l y non-body c o n t a c t b e h a v i o u r even i n i n t e r a c t i o n s l a s t i n g s e v e r a l m i n u t e s , when t h e i n t e r a c t i o n d u r a t i o n c o u l d permit p h y s i c a l c o n t a c t . On s e v e r a l o c c a s i o n s d u r i n g i n t e r s p e c i f i c i n t e r a c t i o n s , c a l i f o r n i a n u s males were observed m i m i c k i n g b e h a v i o u r p a t t e r n s and j o i s t i n g s t r a t e g i e s g e n e r a l l y a s s o c i a t e d w i t h J - j u b a t u s . These m i m i c k r i e s o f t e n corresponded t o a n o t i c e a b l e i n c r e a s e i n e x p r e s s e d a g g r e s s i o n on t h e p a r t of the Z. c a l i f o r n i a n u s p a r t n e r . A l a c k of metacommunication ( B e k o f f , 1972) between t h e two s p e c i e s was o b s e r v e d on s e v e r a l o c c a s i o n s . I f the s u b o r d i n a t e p o s t u r e i s used by one p a r t n e r d u r i n g an 109 i n t r a s p e c i f i c i n t e r a c t i o n , the o t h e r p a r t n e r r a r e l y t r i e s t o p r o l o n g the i n t e r a c t i o n . D u r i n g i n t e r s p e c i f i c i n t e r a c t i o n s t h a t l a s t f o r more than c a . 15 seconds, t h e r e v e r s e i s t r u e . I f a Z. c a l i f o r n i a n u s male t r i e s t o t e r m i n a t e an i n t e r a c t i o n by l o w e r i n g i t s e l f i n the s u b o r d i n a t e p o s i t i o n and s l o w l y moving away, t h e E. j u b a t u s p a r t n e r g e n e r a l l y f o l l o w s and c o n t i n u e s n i p p i n g at t h e s u b o r d i n a t e member. The c o n f u s i o n of t h e r e t r e a t i n g Z. c a l i f o r n i a n u s male i s e x p r e s s e d i n h i s v o c a l i z a t i o n . D u r i n g Z. c a l i f o r n i a n u s i n t r a s p e c i f i c i n t e r a c t i o n s , t h e " d e f e a t e d " s u b o r d i n a t e p a r t n e r always ceases b a r k i n g as soon as i t s t a r t s t o move away. But i n i n t e r s p e c i f i c i n t e r a c t i o n s , i f the E. j u b a t u s p a r t n e r p e r s i s t s , t h e Z. c a l i f o r n i a n u s p a r t n e r o f t e n c o n t i n u e s v o c a l i z i n g l o u d l y as i t r e t r e a t e s . DISTRIBUTION One would e x p e c t dominant a n i m a l s t o occupy the p h y s i c a l - e n v i r o n m e n t a l l y p r e f e r r e d h a u l o u t a r e a s on the i s l a n d . S e v e r a l f a c t o r s o t h e r than e n v i r o n m e n t a l exposure are i m p o r t a n t t o t h e d i s t r i b u t i o n p a t t e r n of sea l i o n s . C o n s i d e r a t i o n must f i r s t be g i v e n t o t h e re a s o n s f o r sea l i o n s h a u l i n g out on l a n d . They do not have t h e buoyancy c a p a c i t y t o s l e e p i n t h e water and must t h e r e f o r e seek l a n d f o r a r e s t i n g a r e a ( S p a l d i n g , 1964). S e c o n d l y , sea l i o n s must bear t h e i r young on l a n d . As a r e s u l t , b e h a v i o u r a l c o n d i t i o n i n g and l e a r n i n g , as i t r e l a t e s t o r e p r o d u c t i o n , s h o u l d take p l a c e on l a n d . Thus even though a c t u a l b r e e d i n g i s not t a k i n g p l a c e on the h a u l o u t areas 110 d u r i n g t h e " w i n t e r " months, the b e h a v i o u r a l seguences a r e b e i n g l e a r n e d and p r a c t i c e d i n p r e p a r a t i o n f o r l a n d o r i e n t e d r e p r o d u c t i o n . Area H i s t h e most p r o t e c t e d h a u l o u t a r e a on F o l g e r I s l a n d . S i n c e exposure t o wind would i n c r e a s e the energy e x p e n d i t u r e of a hauled out sea l i o n (Whittow et a l . , 1973), Area H would appear to be the most p r e f e r r e d h a u l o u t s i t e , as such one would expect t h e dominant a n i m a l s (EOB) t o be found t h e r e r a t h e r than on area B which i s much more exposed. I n s t e a d area H i s p r e d o m i n a n t l y o c c u p i e d by E I B , EIB, ZIB and ZYB. At l e a s t two f a c t o r s are i m p o r t a n t . (1) In o r d e r t o m a i n t a i n a t e r r i t o r y f o r a p e r i o d of two or more months w i t h o u t f e e d i n g , EOB must s t o r e l a r g e energy r e s e r v e s i n the form of f a t . No r e s e a r c h has d e t e r m i n e d when the s e f a t r e s e r v e s are a c c u m u l a t e d , but g e n e r a l o b s e r v a t i o n s on F o l g e r I s l a n d i n d i c a t e t h a t i t i s a g r a d u a l p r o c e s s , l i k e l y o c cupying the m a j o r i t y o f t h e non-b r e e d i n g s e a s o n , s i n c e t h e y get p r o g r e s s i v e l y f a t t e r t h r o u g h o u t the w i n t e r . The a c t i v i t y f requency o f EOB on A r e a H i s much h i g h e r than on Area B and l i k e l y r e s u l t s from harassment and a g e n e r a l l y i n c r e a s e d l e v e l o f a c t i v i t y caused by the EIB and EYB p r e s e n t . A l l c l a s s e s would p r o b a b l y p r e f e r t o occupy the p r e f e r e n t i a l h a u l o u t a r e a s and w i l l do so u n l e s s i t i s e n e r g e t i c a l l y advantageous f o r the dominant ani m a l s to e x c l u d e them, Because o f t h e e x t e n t o f beach space on Area H and r e s u l t a n t easy a c c e s s t o and from the water, a l a r g e amount o f energy would be expended by EOB i n p r e v e n t i n g EIB, 111 EYB, ZIB and ZYB from h a u l i n g o u t . T h i s l a r g e e x p e n d i t u r e of energy would f a r out-weigh the s l i g h t i n c r e a s e i n energy e x p e n d i t u r e r e s u l t i n g from t h e i n c r e a s e d a c t i v i t y f r e g u e n c y o r the a d d i t i o n a l e n e r g y expended by h a u l i n g out on a s l i g h t l y l e s s e n v i r o n m e n t a l l y p r e f e r r e d s i t e such as area B. A c c e s s t o Area B i s made p r i m a r i l y v i a two narrow r a v i n e c o r r i d o r s . The mere presence of EOB near t h e s e c o r r i d o r s appears enough t o p r e v e n t EIB and EYB from h a u l i n g out on Area B. Thus t h e amount of energy used by EOB t o keep younger males from Area B i s m i n i m a l . (2) The optimum amount of l e a r n i n g w i l l t a k e p l a c e i f one's n e i g h b o u r s a r e peers or s l i g h t l y dominant animals or a n i m a l s o f t h e o p p o s i t e sex ( D i n g l e and C a d w e l l , 1969; G e i s t , 1968, 1971; flarestad 1973). From a b e h a v i o u r a l development p e r s p e c t i v e , i t would be d i s a d v a n t a g e o u s f o r EOB t o be expending energy i n t e r a c t i n g w i t h s u b o r d i n a t e male c l a s s e s found on Area H. Thus t h e a d d i t i o n a l energy expended i n k e e p i n g warm on the l e s s e n v i r o n m e n t a l l y f a v o u r a b l e Area B i s l i k e l y much l e s s than the energy t h a t would be u t i l i z e d d u r i n g i n t e r a c t i o n s w i t h s u b o r d i n a t e c l a s s e s on Area H and l e s s than t h e energy needed t o c o n t i n u a l l y p r e v e n t the s u b o r d i n a t e c l a s s e s from h a u l i n g out on Area H. Females r e p e a t e d l y h a u l e d out on Area A. Those t h a t t r i e d t o h a u l out on Area H were i m m e d i a t e l y h a r a s s e d by EIB and EYB and d i d not r e t u r n t o t h a t a r e a . Females were a l s o h a r r a s s e d by EIB on Area A but t o a l e s s e r e x t e n t s i n c e fewer EIB were p r e s e n t (Area A i s a l e s s p r e f e r r e d a r e a than H) and because the broken t e r r a i n r e s t r i c t e d EIB m o b i l i t y 112 and a f f o r d e d EOB t h e o p p o r t u n i t y t o e x c l u d e EIB. Area A i s g e n e r a l l y more exposed than Area B. S i n c e females were c o m p l e t e l y p r o t e c t e d from EIB harassment on Area B and n o t chased away by EOB, one would expect t h a t ECS would f r e q u e n t Area B q u i t e o f t e n . T h i s a t t r a c t i o n of females t o Area B d i d not o c c u r and may be a r e s u l t of f e m a l e b e h a v i o u r and pup p h y s i o l o g y . Females a r e e x t r e m e l y g r e g a r i o u s . Even i f a l a r g e a r e a i s a v a i l a b l e t o permit s p a c i n g of f e m a l e s , t h e females w i l l crowd t o g e t h e r i n a s m a l l a r e a . S e c o n d l y , the pups are much more s u s c e p t a b l e t o c o l d than a r e a d u l t a n i m a l s because o f t h e i r l a r g e r s u r f a c e t o volume r a t i o . The f e m a l e s a r e e x c l u d e d from the " p r o t e c t e d " h a u l o u t areas due t o harassment by EIB and EYB, but must s t i l l f i n d a p l a c e t o s u c k l e t h e i r pups where the l a t t e r a r e not exposed t o c h i l l i n g winds. The n o r t h w e s t e r n s i d e of the c e n t r a l r o c k p i n n a c l e of Area A s a t i s f i e s the r e q u i r e m e n t s of females w i t h s u c k l i n g young. Such a l o c a t i o n i s not found on Area B. Thus females w i t h pups r e p e a t e d l y r e t u r n to t h e s m a l l p r o t e c t e d s i t e on Area A and the g r e g a r i o u s nature of the o t h e r f e m a l e s may have caused them to a l s o h a u l out on Area A. Both c l a s s e s of Z. c a l i f o r n i a n u s are found o n l y where they are not exposed t o t h e wind. T h i s i s i n d i r e c t c o n t r a s t t o r e s u l t s found by P e t e r s o n and Bartholomew (1967) who s t a t e t h a t Z. c a l i f o r n i a n u s r o o k e r i e s are l o c a t e d on the windward s i d e of i s l a n d s . I n C a l i f o r n i a , where i t i s h o t t e r , the emphasis appears t o be on keeping c o o l , whereas i n B r i t i s h Columbia the d i s t r i b u t i o n i s b e t t e r e x p l a i n e d i f i t i s assumed t h a t t h e y are t r y i n g t o keep warm. 113 B e h a v i o u r a l a d a p t a t i o n s f o r r e g u l a t i n g heat l o s s i n p i n n i p e d s have been observed by s e v e r a l a u t h o r s (Bartholomew and W i l k e , 1956; P a u l i a n , 1964; P e t e r s o n and Bartholomew, 1967; Fay and Bay, 1968; I r v i n g , 1969; G e n t r y , 1970). The s h i v e r i n g b e h a v i o u r and e x t e n s i v e crowding d u r i n g c o l d weather s u g g e s t t h a t Z. c a l i f o r n i a n u s i s much more s u s c e p t i b l e t o c o l d t e m p e r a t u r e s than i s E. -jubatus. T h i s d i f f e r e n c e i n t h e r m a l t o l e r a n c e i s l i k e l y a r e s u l t of p h y s i o l o g i c a l d i f f e r e n c e s between E. -jubatus and Z. c a l i f o r n i a n u s s i n c e s m a l l EYB and ECS were not observed s h i v e r i n g , whereas ZIB and ZYB of comparable s i z e were o f t e n seen s h i v e r i n g . S i n c e a wet a n i m a l l o s e s more heat energy t o t h e environment than a dry one (Hart e t a l . , 1961), Z. c a l i f o r n i a n u s males occupy t h e uppermost r e a c h e s o f t h e beaches, f u r t h e s t from the waves and wind d r i v e n s p r a y and under t h e o v e r h a n g i n g c l i f f s , t r e e s and l o g s . Sandegren (1970) mentions t h a t E. j u b a t u s " a r e a g u a t o p h i l e s and are r a r e l y seen hauled c u t more than 20 m. away from water. R e p e a t e d l y , the a n i m a l s can be seen stampeding down t o t h e w a t e r s ' edge or i n t o the water when the o u t g o i n g t i d e l e a v e s them t o o f a r from t h e s e a . " These mass stampedes were never observed i n t h i s s t u d y but E. •Si§tii§ d i d t e n d t o occupy the s e c t i o n of beach b o r d e r i n g on the h i g h t i d e l e v e l . Space was not a l i m i t i n g f a c t o r on any of t h e h a u l o u t areas o c c u p i e d by both Z. c a l i f o r n i a n u s and !• j u h a t u s so each s p e c i e s was a b l e t o occupy i t s own t e r r e s t r i a l n i c h e w i t h no i n t e r s p e c i f i c c o m p e t i t i o n . 1 14 IMPLICATIONS OF INVESTIGATIVE BEHAVIOUR I n v e s t i g a t i v e b e h a v i o u r i s used more f r e q u e n t l y by E. j u b a t u s males t h a n by Z. c a l i f o r n i a n u s males and t h i s d i f f e r e n c e i s r e f l e c t e d i n male-female i n t e r a c t i o n s on the b r e e d i n g r o o k e r y . Male E. j u b a t u s p l a y an e x t e n s i v e r o l e i n p r e c o p u l a t o r y behaviour (Gentry, 1970). A l l new f e m a l e s e n t e r i n g a t e r r i t o r y a r e "nosed" i n t h e p e r i a n a l r e g i o n t o check f o r s i g n s o f e s t r u s . In c o n t r a s t male Z. c a l i f o r n i a n u s a r e a c t i v e l y s o l i c i t e d by f e m a l e s i n e s t r u s and e x h i b i t very l i t t l e p r e c o p u l a t o r y a c t i v i t y ( P e t e r s o n and Bartholomew, 1967). Thus i t i s not unexpected t h a t male c l a s s e s of Z. c a l i f o r n i a n u s show low l e v e l s o f i n v e s t i g a t i v e b e h a v i o u r . G e i s t (1971) observed t h a t o l d e r male mountain sheep t r e a t younger a n i m a l s , male and f e m a l e , as i f they were f e m a l e s . To a c e r t a i n e x t e n t t h i s i s a l s o t r u e f o r E. j u b a t u s . I n v e s t i g a t i v e b e h a v i o u r i s used by EOB and even more e x t e n s i v e l y by EIB towards EYB and both c l a s s e s of Z. c a l i f o r n i a n u s males. In a d d i t i o n attempted c o p u l a t i o n s are d i r e c t e d by EIB a t EYB, ZIB and ZYB. The d a t a i n d i c a t e t h a t as males mature the v a r i a b i l i t y o f i n v e s t i g a t i v e b e h a v i o u r p a t t e r n s used d e c r e a s e s . T h i s may mean t h a t o l d e r a n i m a l s a r e a b l e t o r e c o g n i z e a t t r i b u t e s of t h e i r p a r t n e r by means o t h e r than o l f a c t i o n , o r t h a t the o l d e r a n i m a l s j u s t have no need t o use a l l o f t h e i n v e s t i g a t i v e b e h a v i o u r p a t t e r n s a t t h e time o f y e a r t h a t they a r e b e i n g o b s e r v e d . O l d males may i n f a c t use a l l t y p e s o f i n v e s t i g a t i v e b e h a v i o u r d u r i n g t h e season f o r which 115 i t i s most advantageous t o do s o . As an example, my data show t h a t no c o p u l a t o r y o r i e n t e d b e h a v i o u r p a t t e r n s were performed by EOB. A premature c o n c l u s i o n may t h e r e f o r e be t h a t EOB do not c o p u l a t e . However, a t o t h e r t i m e s o f year EOB are o b s e r v e d c o p u l a t i n g . THE CONSPICUOUS ABSENCE OP ZALOPHUS FEMALES AND PUPS The b r e e d i n g range of Z. c a l i f o r n i a n u s o c c u p i e s a much warmer c l i m a t e than does t h a t o f E. j u b a t u s ( S c h e f f e r , 1958). Davies (1958) s p e c u l a t e s t h a t Z. c a l i f o r n i a n u s has n ever bred n o r t h of t h e 10 degree c e n t i g r a d e i s o t h e r m . I n accordance w i t h t h i s i t i s e x p e c t e d t h a t Z. c a l i f o r n i a n u s would be p h y s i o l o g i c a l l y adapted t o a warm c l i m a t e . At p r e s e n t F o l g e r I s l a n d i s the most n o r t h e r n p o i n t where Z. c a l i f o r n i a n u s males a r e found i n l a r g e numbers ( B i g g , 1973). No r e s e a r c h has been conducted t o determine why Z. c a l i f o r n i a n u s males m i g r a t e n o r t h i n t h e w i n t e r months. S e v e r a l a u t h o r s have s p e c u l a t e d t h a t f o o d r e s o u r c e s a r e more p l e n t i f u l i n B r i t i s h Columbia but no q u a n t i t a t i v e d a t a are g i v e n ( F r y , 1939; Bartholomew and Hubbs, 1952; Bartholomew and B o o l o o t i a n , 1960; Orr and F o u l e r , 1965; Mate, 1973). I f Z. c a l i f o r n i a n u s males m i g r a t e n o r t h d u r i n g t h e non-b r e e d i n g s e a s o n , why don't the pups and females? Indeed the f e m a l e s and pups make a s h o r t southward m i g r a t i o n (Mate, 1973). Eumetopias j u b a t u s f e m a l e s and pups a r e known to t r a v e l up t o s e v e r a l hundred m i l e s i n e a r l y f a l l ( F i s h e r , H.D., p e r . com.), so we might e x p e c t Z. c a l i f o r n i a n u s to have s i m i l a r v a g i l i t y . 116 A comparison between pup s i z e f o r the two s p e c i e s i n l a t e August (when males a r e m i g r a t i n g n o r t h , Mate 1973) shows E. -jubatus pups at c a . 30 kg. and Z. c a l i f o r n i a n u s pups at c a . 15 kg. ( F i s h e r , H.D., per. com.). Using t h e K l e i n e r (196 1) body w e i g h t - m e t a h o l i c r a t e r e l a t i o n s h i p , such d i f f e r e n c e s i n body weight would produce a m e t a b o l i c r a t e per kg. of body weight, 10% h i g h e r f o r the Z. c a l i f o r n i a n u s pups than t h e E. j u b a t u s pups. I n a d d i t i o n Z. c a l i f o r n i a n u s pups do not m a i n t a i n the f a t l a y e r s t h a t are apparent on t h e E. j u b a t u s pups soon a f t e r b i r t h ( F i s h e r , H.D., per. com.). M a r i o s (1975) mentions t h a t P h o c a r c t o s h c o k e c i pups t h a t have not y e t developed a l a y e r o f b l u b b e r " s h i v e r v i o l e n t l y " i n wet windy c o n d i t i o n s . L e n f a n t e t a l . (1970) found t h a t sea l i o n pups have v e r y low l e v e l s of myoglobin i n t h e muscle t i s s u e . T h i s low m y o g l o b l i n l e v e l may reduce the d i s t a n c e t h a t pups a r e a b l e t o swim. The h i g h e r energy c o s t , reduced f a t and reduced muscle myoglobin c o u l d be s u f f i c i e n t t o p r e v e n t 2. c a l i f o r n i a n u s pups from s u c c e s s f u l l y m i g r a t i n g n o r t h and e x p l a i n why they m i g r a t e s l i g h t l y s o u t h where the c l i m a t e i s warmer d u r i n g t h e w i n t e r . L a c t a t i n g females accompany t h e i r pups and the g r e g a r i o u s n a t u r e o f f e m a l e s may i n d u c e the o t h e r s t o f o l l o w . A l s o Z. c a l i f o r n i a n u s f e m ales a r e of a s i z e comparable t o , and s m a l l e r t h a n ZYB. The i n c r e a s e d s u r f a c e -to-volume r a t i o o f females compared t o males and hence h i g h e r energy l o s s f o r . females c o u l d p r e v e n t t h e f e m a l e s from v e n t u r i n g n o r t h w a r d . T h i s s e x u a l s e p a r a t i o n c o u l d be e x t r e m e l y u s e f u l i n terms o f r e s o u r c e p a r t i t i o n i n g . The males l e a v e the 117 b r e e d i n g a r e a s shen the f e m a l e s are s t i l l s u c k l i n g pups. As such females would not t e competing w i t h males f o r food r e s o u r c e s d u r i n g a time when n u t r i t i o n a l r e q u i r e m e n t s of l a c t a t i n g f e m ales would be h i g h . FEMALE AND POP INFLUENCE ON SOCIAL OHDER The i n f l u e n c e of f e m a l e s on the t e r r i t o r i a l i t y of p i n n i p e d s p e c i e s has been observed by s e v e r a l a u t h o r s (Bartholomew, 1951; Laws, 1956; Hewer and Backhouse, 1960; Kenyon, 1962; Band, 1967). H a r e s t a d (1973) s u g g e s t s t h a t f e m a l e s may a c t as a r e l e a s i n g mechanism e l i c i t i n g t e r r i t o r i a l b e h a v i o u r i n males. T h i s i s not n e c c e s s a r i l y so. Eumetopias j u b a t u s and Z. c a l i f o r n i a n u s males e s t a b l i s h t e r r i t o r i e s b e f o r e f e m a l e s a r r i v e a t the b e g i n n i n g of t h e b r e e d i n g season (Gentry, 1970; P e t e r s o n and Bartholomew, 1967). S e v e r a l i n s t a n c e s of a p p a r e n t female i n d u c e d t e r r i t o r i a l b e h a v i o u r were observed a t F o l g e r I s l a n d . A lthough no p r e c i s e b o u n d a r i e s were e s t a b l i s h e d , an area i n which f e m a l e s were l o c a t e d was o f t e n a c t i v e l y defended by an EOB a g a i n s t e n t r y by o t h e r males. No attempted c o p u l a t i o n s were made by t h e s e " t e r r i t o r i a l males". Gentry (1970) and Sandegren (1970) mention t h a t t e r r i t o r i a l b u l l s on b r e e d i n g r o o k e r i e s do not attempt t o mate w i t h females u n l e s s the l a t t e r a r e i n e s t r u s and p e r f o r m i n g " p r e c o p u l a t o r y " d i s p l a y s . On t h e b r e e d i n g r o o k e r y o n l y e s t r o u s females are a c t i v e l y herded by males. Thus i t would appear t h a t EOB's are aware t h a t t h e f e m a l e s on the w i n t e r h a u l o u t areas are not i n a c o n d i t i o n t h a t w a r r a n t s s e x u a l advance whereas the 118 EIB's a r e not aware o f the s e x u a l s t a t e o f t h e f e m a l e s . The i n f l u e n c e of pups on the s o c i a l o r d e r of the ha u l o u t a r e a appears n e g l i g i b l e , y e t i n d i r e c t l y t h e y have an i m p o r t a n t i m p a c t . Females w i t h pups a r e much more a l e r t t han t h o s e w i t h o u t . The area a v a i l a b l e f o r s u c k l i n g pups i s r e s t r i c t e d and these f e m a l e s o f t e n p h y s i c a l l y e x c l u d e o t h e r a n i m a l s from e n t e r i n g the i m m e d i a t e l y s u r r o u n d i n g a r e a . As a r e s u l t a " l o o s e " t e r r i t o r i a l system i s m a i n t a i n e d by l a c t a t i n g f emales- A l l c l a s s e s were observed b e i n g f o r c e d from t h i s a r e a . J u s t a s f e m a l e s may be a r e l e a s i n g mechanism f o r male t e r r i t o r i a l i t y on h a u l o u t grounds, so may pups s t i m u l a t e t e r r i t o r i a l b e h a v i o u r i n f e m a l e s . On b r e e d i n g r o o k e r i e s EIB and EOB a r e c o n t i n u a l l y r e p e l l e d by t h e t e r r i t o r i a l b u l l . T h i s c r e a t e s a " q u i e t r e f u g e " w i t h i n the t e r r i t o r y where pups are r e l a t i v e l y s a f e from i n j u r y by f i g h t i n g o r t r a n s i e n t b u l l s . On the ha u l o u t ground t h e male t e r r i t o r i e s are not s t r i c t l y e n f o r c e d and the r e f u g e s f o r pups c r e a t e d by t e r r i t o r i e s a r e th e n m a i n t a i n e d by t h e mothers o f t h e pups. T h i s t e r r i t o r i a l b e h a v i o u r of f e m a l e s may i n d i c a t e t h a t females w i t h pups a r e h i g h e r i n t h e dominance h i e r a r c h y rank than females w i t h o u t pups, EYB and, i n some i n s t a n c e s , even EIB. A l t h o u g h the p r o t e c t i o n of pups by t h e females d u r i n g the l a c t a t i o n p e r i o d i s of p h y s i c a l advantage t o t h e pups, i t may be s o c i a l l y d i s a d v a n t a g e o u s . The pups on F o l g e r I s l a n d do not i n t e r a c t w i t h o t h e r pups and o n l y r a r e l y i n t e r a c t w i t h c l a s s e s o t h e r than ECS. T h i s i s i n d i r e c t c o n t r a s t t o the pup a g g r e g a t i o n s r e p o r t e d by Gentry (1970) and Sandegren (1970). The r e s t r i c t i o n of s o c i a l i n t e r a c t i o n 119 f o r a n i m a l s i n e a r l y development o f t e n produces marked impairment o f s o c i a l a b i l i t i e s i n l a t e r l i f e (Mason, 1960; S c h a l l e r , 1967; G i l b e r t , 1968; Fox, 1971; B e k o f f , 1972). Some sea l i o n pups a r e weaned w i t h i n t h r e e months o f b i r t h w h i l e o t h e r s may s u c k l e f o r up t o two y e a r s . Sandegren (1970) found t h a t more than 50% of t h e females r e t u r n e d t o the r o o k e r y ( i n A l a s k a ) w i t h y e a r l i n g s . P r e l i m i n a r y i n v e s t i g a t i o n s f o r B r i t i s h Columbia i n d i c a t e about 30% ( E d i e , A., p e r . com.) and G e n t r y (1970) found o n l y 2% i n C a l i f o r n i a . A comparison between the s o c i a l ontogeny o f E. J u s t u s c l a s s e s i n A l a s k a , B r i t i s h Columbia and C a l i f o r n i a c o u l d be used to t e s t whether p r o l o n g e d female-pup a s s o c i a t i o n s have any e f f e c t on the s o c i a l development of pups as they mature. There have been no s e x - r a t i o c ensuses done f o r s u c k l i n g y e a r l i n g s . Male sea l i o n s t y p i c a l l y have g r e a t e r i n v o l v e m e n t i n s o c i a l i n t e r a c t i o n s , a more complex and d i v e r s e r e p e r t o i r e of b e h a v i o u r a l p a t t e r n s and g r e a t e r independence than have f e m a l e s (Harestad 1973). I f the m a j o r i t y o f s u c k l i n g y e a r l i n g s a r e f e m a l e s , t h e n the o v e r a l l impact of s o c i a l r e t a r d a t i o n on t h e p o p u l a t i o n may not be i m p o r t a n t . The extended s u c k l i n g p e r i o d may, i n f a c t , i n c r e a s e t h e s u r v i v a l r a t e and f i t n e s s c f young females a l l o w i n g them t o breed a t a younger age. Such e f f e c t s o f p r o l o n g e d s u c k l i n g and h a s tened s e x u a l m a t u r i t y a r e r e p o r t e d f o r r e i n d e e r and c a r i b o u (McEwan and Whitehead, 1972) . 120 A COMPARATIVE LOOK AT SPECIES AGGRESSION AND THERMOREGULATORY INFLUENCE Eumetppias j u b a t u s males do n o t r e q u i r e " h u d d l i n g " t o keep warm. Zal o p h u s c a l i f o r n i a n u s males use p h y s i c a l c o n t a c t and h u d d l i n g as a method of r e t a i n i n g body heat d u r i n g t h e c o l d w i n t e r . The c r o w d i n g of Z. c a l i f o r n i a n u s c o u l d not o c c u r i f i n d i v i d u a l s were a g g r e s s i v e towards t h e i r n e i g h b o u r s . The low l e v e l of a g g r e s s i v e n e s s i n Z. c a l i f o r n i a n u s may p e r m i t t h i s s p e c i e s t c aggregate more c l o s e l y than the more a g g r e s s i v e E. j u b a t u s males. The h i g h e r a g g r e s s i v e t e n d e n c i e s o f E. j u b a t u s males, as compared t o Z. c a l i f o r n i a n u s males, can be r e l a t e d t o d i f f e r e n c e s i n t h e t e r r i t o r i a l maintenance o f t h e two s p e c i e s . Eumetopias j u b a t u s b u l l s e s t a b l i s h and m a i n t a i n t e r r i t o r i e s on r o c k y a r e a s , g e n e r a l l y above the h i g h t i d e l e v e l . The p r e c i s e b o u n d a r i e s of these t e r r i t o r i e s may r e q u i r e e x t e n s i v e f i g h t i n g t o e s t a b l i s h , but they remain f i x e d and r e g u i r e l i t t l e energy t o m a i n t a i n . When a new b u l l i s i n t r o d u c e d i n t o the t e r r i t o r i a l s t r u c t u r e o f t h e r o o k e r y , however, t h e boundary b o r d e r i n g on the new b u l l ' s t e r r i t o r y must be r e - e s t a b l i s h e d , a f t e r which i t g e n e r a l l y remains s t a t i o n a r y . Hence i n t e n s e a g g r e s s i o n i s used i n the e s t a b l i s h m e n t of a t e r r i t o r y and the p o t e n t i a l f o r r e o c c u r r e n c e o r e x p r e s s i o n of t h i s a g g r e s s i o n through a g g r e s s i v e d i s p l a y s m a i n t a i n s the b o u n d a r i e s t h e r e a f t e r . Zalophus c a l i f o r n i a n u s males 0 defend b r e e d i n g t e r r i t o r i e s which are i n f l u e n c e d by the t i d e s . The females h a u l out j u s t above th e t i d a l l e v e l but f o l l o w i t up and 121 down the sandy beach i n o r d e r t o s t a y a t the water's edge and keep c o o l . The t e r r i t o r i a l b u l l s f o l l o w the females on t h e s e movements. As a r e s u l t the b u l l s ' t e r r i t o r i e s and t h e i r b o u n d a r i e s are c o n t i n u a l l y s h i f t i n g . I f a b u l l were to a c t i v e l y defend and r e - e s t a b l i s h t h e s e boundary l i m i t s w i t h each t i d e change he would have no energy or time t o c o p u l a t e w i t h f e m a l e s . F u r t h e r e v i d e n c e of the reduced a g g r e s s i v e n e s s and l e s s e x c l u s i v e t e r r i t o r i a l system f o r Z. c a l i f o r n i a n u s i s the f a c t t h a t Z. c a l i f o r n i a n u s b u l l s do not i n t e r r u p t a c o p u l a t i o n t o chase a male i n t r u d e r , whereas E. j u b a t u s male do ( P e t e r s o n and Bartholomew, 1967; G e n t r y , 1970). Harlow (1975) found t h a t P h o c a r c t g s h o o k e r i males which defend t e r r i t o r i e s on sandy beaches are f a r l e s s a g g r e s s i v e and have a more r i t u a l i s t i c r e p e r t o i r e of b e h a v i o u r p a t t e r n s than do Neophoca c i n e r e a males which defend t e r i t o r i e s on r o c k benches. He s p e c u l a t e s t h a t the more r i t u a l i s t i c d i s p l a y s of P. h o o k e r i r e p r e s e n t s a h i g h e r l e v e l of s o c i a l development t h a n t h e a g o n i s t i c b e h a v i o u r of N. c i n e r e a . F r e q u e n t l y Z. c a l i f o r n i a n u s t e r r i t o r i e s a r e w h o l l y a q u a t i c and c o p u l a t i o n s i n t h e s e t e r r i t o r i e s have been observed ( P e t e r s o n and Bartholomew, 1967). I t i s l o g i c a l t h a t a s p e c i e s t h a t i s h i g h l y adapted t o a q u a t i c l i f e and shows s i g n s o f o v e r h e a t i n g w h i l e on the l a n d b r e e d i n g a r e a , s h o u l d e v o l v e towards a q u a t i c c o p u l a t i o n s and even perhaps b i r t h s , as a r e now found i n C e taceans. I t was found on F o l g e r I s l a n d t h a t Z. c a l i f o r n i a n u s males were much more apt t o m a i n t a i n p r o l o n g e d i n t e r a c t i o n s , both i n t e r and i n t r a s p e c i f i c a l l y w h i l e i n t h e water than 122 when on l a n d , T h i s was not t h e case f o r E, -jubatus which breeds i n a more temperate c l i m a t e and does not m a i n t a i n a g u a t i c t e r r i t o r i e s . 123 SUMMARY The f o l l o w i n g c o n c l u s i o n s and hypotheses a r e i n d i c a t e d by t h i s s t u d y . (1) A s i z e - a g e r e l a t e d dominance h i e r a r c h y i s observed on F o l g e r I s l a n d . L a r g e r - o l d e r sea l i o n s a r e dominant t o s m a l l e r - y o u n g e r ones. Male J . j u b a t u s are dominant t o female E. j u b a t u s and male Z. c a l i f o r n i a n u s . (2) C h a l l e n g i n g and i n t e r a c t i n g w i t h dominants a f f o r d s s u b o r d i n a t e s t h e o p p o r t u n i t y t o "move up" the h i e r a r c h y r e l a t i o n s h i p and t o expand t h e i r b e h a v i o u r a l r e p e r t o i r e . (3) The e s t a b l i s h m e n t of dominance h i e r a r c h i e s among males i s i m p o r t a n t f o r energy c o n s e r v a t i o n on the b r e e d i n g r o o k e r i e s and h a u l o u t a r e a s . (4) D u r i n g the e s t a b l i s h m e n t o f dominance r e l a t i o n s h i p s EOB use p r e d o m i n a n t l y non-body c o n t a c t b e h a v i o u r p a t t e r n s , which u t i l i z e l e s s energy than body c o n t a c t b e h a v i o u r p a t t e r n s . EYB use p r e d o m i n a n t l y body c o n t a c t b e h a v i o u r p a t t e r n s . (5) B e h a v i o u r a l sequences used f o r e s t a b l i s h m e n t and maintenance o f dominance a r e l e a r n e d on the non-breeding a r e a s where energy c o n s e r v a t i o n i s not as c r i t i c a l as on the b r e e d i n g r o o k e r y . (6) EIB a r e not aware o f the s e x u a l n o n - r e c e p t i v i t y cf females on the w i n t e r h a u l o u t ground and make r e p e a t e d s e x u a l advances towards f e m a l e s . EOB do not make s e x u a l advances towards f e m a l e s and o f t e n p r o t e c t f e males from EIB harassment. (7) A l a c k o f metacommunication between the two 124 s p e c i e s was observed on s e v e r a l o c c a s i o n s . (8) M i m i c k i n g p l a y s an i m p o r t a n t r o l e i n l e a r n i n g . (9) When Z. c a 1 i f o r n i a n u s males mimic E. j u b a t u s males an i n c r e a s e i n e x p r e s s e d a g g r e s s i o n i s observed f o r the Z. c a l i f o r n i a n u s p a r t n e r . (10) Some f e m a l e s s u c k l e t h e i r pups f o r up t o two y e a r s . T h i s l e n g t h y s u c k l i n g p e r i o d may have two e f f e c t s : ( i ) marked impairment o f s o c i a l a b i l i t i e s i n l a t e r l i f e due to r e s t r i c t i o n of s o c i a l i n t e r a c t i o n s w i t h o t h e r a n i m a l s when th e y a r e pups, o r ( i i ) l o w e r i n g o f the age of a t t a i n m e n t o f s e x u a l m a t u r i t y by p r o v i d i n g h i g h n u t r i e n t l e v e l s f o r t h e young a n i m a l s . (11) As a r e s u l t of an energy " t r a d e - o f f " , EOB occupy a s l i g h t l y l e s s p h y s i c a l - e n v i r o n m e n t a l l y p r e f e r r e d a r e a than do EIB, EYB, ZIB and ZYB. (12) Females a r e f o r c e d from the e n v i r o n m e n t a l l y p r e f e r r e d a r e a s by harassment by EIB and EYB. The g r e g a r i o u s n a t u r e o f t h e females i n d u c e s a l l of t h e fem a l e s t o h a u l out on Area A where l a c t a t i n g f e m a l e s must go t o s u c k l e t h e i r pups. (13) Z a l o j i h u s c a l i f o r n i a n u s c l a s s e s a re i n f l u e n c e d by weather t o a g r e a t e r e x t e n t t h a n a re E. j u b a t u s c l a s s e s and thus occupy o n l y t h e most p r o t e c t e d bays on F o l g e r I s l a n d . (14) The reduced a g g r e s s i v e l e v e l of Z. c a l i f o r n i a n u s males, as opposed t o E. j u b a t u s males, a l l o w s the former s p e c i e s t o crowd t o g e t h e r and r e t a i n body heat d u r i n g c o l d weather. (15) Females appear t o i n d u c e t e r r i t o r i a l b e h a v i o u r i n o l d b u l l s on the w i n t e r h a u l o u t a r e a . 125 (16) Pups appear t o i n d u c e t e r r i t o r i a l b e h a v i o u r i n l a c t a t i n g f e m ales on the w i n t e r h a u l o u t a r e a . (17) Male Z. c a l i f o r n i a n u s do not t a k e p a r t i n p r e c o p u l a t o r y a c t i v i t y on t h e b r e e d i n g r o o k e r y and are observed t o e x h i b i t very l i t t l e i n v e s t i g a t i v e b e h a v i o u r on t h e w i n t e r h a u l o u t a r e a . Eumetopias -jubatus males do p a r t a k e i n p r e c o p u l a t o r y a c t i v i t y on the b r e e d i n g r c o k e r y and are observed p e r f o r m i n g i n v e s t i g a t i v e b e h a v i o u r on t h e w i n t e r h a u l o u t a r e a . (18) Zalophus c a l i f o r n i a n u s , which breed i n a warmer c l i m a t e than do E. j u b a t u s , o f t e n m a i n t a i n , and c o p u l a t e i n , a g u a t i c t e r r i t o r i e s , whereas E. j u b a t u s do n o t . Zalophus c a l i f o r n i a n u s males on F o l g e r I s l a n d were observed j o u s t i n g f o r extended p e r i o d s p r e d o m i n a n t l y i n a few meters o f water, whereas E. j u b a t u s males g e n e r a l l y j o u s t cn l a n d or i n water l e s s than one meter deep-126 ACKNOWLEDGEMENTS I am s i n c e r e l y g r a t e f u l t o Dr. H. Dean F i s h e r f o r h i s a s s i s t a n c e and t o l e r a n c e d u r i n g t h i s s t u d y . I thank Diane Slobodan f o r the t y p i n g o f , and Dr. R.M.F.S. S a d l e i r , Dr. J.M. T a y l o r , Dr. J.N. M. S m i t h , Dr. G.G.E. Scudder, A l t o n H a r e s t a d and John Keays f o r t h e i r r e v i e w and c r i t i c i s m of the manuscipt. S p e c i a l thanks t o the E a m f i e l d Coast Guard, the members o f t h e B a m f i e l d community and p a r t i c u l a r l y the s t a f f of the B a m f i e l d Marine S t a t i o n . w i t h o u t t h e i r h e l p t h i s s t u d y would not have been p o s s i b l e . I a l s o wish t o e x p r e s s my g r e a t e s t a p p r e c i a t i o n t o Mr-L a r r y B o r g e r s o n , my f i e l d a s s i s t a n t and c o l l e a g u e , who I am sure i s a s e a l i o n i n d i s g u i s e . The r e s e a r c h was f i n a n c e d by N a t i o n a l R e s e a r c h C o u n c i l g r a n t A 2019 and the U n i v e r s i t y G r a n t s O f f i c e o f t h e F e d e r a l F i s h e r i e s and Marine S e r v i c e o f Canada. I 127 BIBLIOGRAPHY A l l e e , S.C. 1951. C o - o p e r a t i o n Among A n i m a l s , With Human I m p l i c a t i o n s . Henry Schuman, New York. 233 p. Anon. 1975. Sea l i o n (Eumetopias j u b a t a ) . A l a s k a Department of F i s h and Game. 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