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The identification and distribution of two species of Peromyscus in southeastern Ontario Lanko, Joyce Laurian 1962

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THE IDENTIFICATION AND DISTRIBUTION OF TWO SPECIES OF PEROMYSCUS IN SOUTHEASTERN ONTARIO by JOYCE LAURIAN LANKO A thesis submitted i n partial fulfilment of the requirements for the degree of MASTER OF SCIENCE in the Department of Zoology We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA MAY, 1962 In presenting 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 requirements f o r an advanced degree a t the U n i v e r s i t y of B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r reference and study. I f u r t h e r agree that permission f o r extensive copying of t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the Head of my Department 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 understood t h a t copying or p u b l i c a t i o n of t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be allowed without my w r i t t e n permission. Department of Zoology The U n i v e r s i t y of B r i t i s h Columbia, Vancouver 3, Canada, Date May 7, 1962 11 . ABSTRACT One hundred and sixty-nine mice of Peromyscus leucopus noveboracensis and Peromyscus maniculatus g r a c i l i s were examined for characters to best separate them. Each species was obtained from an area i n Ontario where i t was known to be the only one present. An additional 12 mice of both species were obtained from an area of sympatry. The best characters found to separate them were, i n order of importance: ear length, i n t e r p a r i e t a l length, t a i l length, s k u l l length, and r o s t r a l length. Although ear length and i n t e r p a r i e t a l length separated most of the indi v i d u a l s , there were s t i l l i ndividuals that could not be separated. The two species were found to be completely separable, using either one of two indices: Ear length X t a l l length X i n t e r p a r i e t a l length s k u l l length or, Ear length X t a i l length X i n t e r p a r i e t a l length r o s t r a l length With s k u l l length, P. 1 . noveboracensis has an index value of 2 . 5 7 - 4 . 0 9 and P. m. g r a c i l i s has an index value of 4.26 - 7 . 9 0 . With r o s t r a l length, P. 1 . noveboracensis has an index value of 7 . 3 9 - 1 2 . 5 0 and P. m. g r a c i l i s has an index value of 1 2 . 8 3 - 2 2 . 7 7 . Six crossbreeding experiments were attempted between P. 1 . noveboracensis and four subspecies of P. maniculatus. The animals were kept together for periods ranging from 71 days to over a year. No o f f s p r i n g resulted. Three pairs of P. leucopus and four pairs of P. maniculatus were kept for the same periods of time i n the same room, as a control. One pair of leucopus prod-uced two l i t t e r s , another p a i r produced one, and the t h i r d pair, none. Two pairs of maniculatus produced one l i t t e r each and the i i i . two p a i r s , none. P. m. g r a c i l i s was not as e x c i t a b l e or nervous as P. 1. noveboracensis and was t h e r e f o r e e a s i e r t o handle. Although the ranges o f P. 1. noveboracensis and P. m. g r a c i l i s d i f f e r , the mice meet i n a zone o f o v e r l a p where they occur s y m p a t r i c a l l y . C o r r e l a t i o n s were made between the ranges of the mice and v e g e t a t i o n , food p r e f e r e n c e , temperature t o l e r a n c e , water requirement, morphology, c o l o r of pelage, and beh a v i o r . P. m. g r a c i l i s was found to occur i n c o n i f e r o u s and P. 1. noveboracensis In deciduous v e g e t a t i o n . No c o r r e l a t i o n was found between the ranges o f the mice and food p r e f e r e n c e , temperature t o l e r a n c e , water requirement, morphology, and c o l o r of pelage. C o r r e l a t i o n between the ranges o f the mice and t h e i r b e h a v i o r was d o u b t f u l . P r e l i m i n a r y t e s t s were made of the a b i l i t y o f one s p e c i e s to d i s c r i m i n a t e between i t s odor and th a t o f the other s p e c i e s . R e s u l t s showed t h a t a mouse entered more o f t e n and stayed l o n g e r i n a chamber c o n t a i n i n g the odor of i t s own s p e c i e s . A chamber c o n t a i n i n g odor o f e i t h e r s p e c i e s was p r e f e r r e d to the c o n t r o l chamber without odor. We accept t h i s t h e s i s as conforming to the r e q u i r e d standard i v . TABLE OF CONTENTS ABSTRACT page i i TABLE OF CONTENTS i v LIST OF FIGURES v i i ACKNOWLEDGMENTS i x THE IDENTIFICATION AND DISTRIBUTION OF TWO SPECIES OF PEROMYSCUS IN SOUTHEASTERN ONTARIO INTRODUCTION 1 Breeding Experiments 5 Other Species of Peromyscus i n Southeastern Ontario 6 D i s t r i b u t i o n of leucopus and maniculatus 6 Summary of the Problem 9 THE TAXONOMIC SEPARATION OF PEROMYSCUS LEUCOPUS  NOVEBORACENSIS AND PEROMYSCUS MANICULATUS GRACILIS MATERIALS AND METHODS Co l l e c t i o n of Specimens Preparation of Specimens Features Selected f o r Measurement Number of Animals Used Methods of Data Analysis Experiments i n Interbreeding Factors Influencing D i s t r i b u t i o n Experiments i n Odor Discrimination THE SEARCH FOR GOOD CHARACTERS TO SEPARATE THE SPECIES RESULTS AND CONCLUSIONS Weight Hind foot length Ear length 11 12 13 15 15 16 16 17 18 19 19 20 V. Body length 20 T a i l length 21 I n t e r p a r i e t a l width 22 I n t e r p a r i e t a l length 22 S k u l l length 23 Rostral length 23 Baculum length 23 The Separation of leucopus and maniculatus Using Morphological Characters 24 The Character Index for the Separation of leucopus and maniculatus 26 Tests of Indices 29 Tests of the Indices on Mice From an Area of Sympatry 30 Summary of the indices 31 Results of Crossbreeding 32 THE DISTRIBUTION OF PEROMYSCUS LEUCOPUS NOVEBORACENSIS AND PEROMYSCUS MANICULATUS GRACILIS 34 History of D i s t r i b u t i o n of Peromyscus 34 Present D i s t r i b u t i o n of Peromyscus i n Ontario 35 Correlation of Ranges of Mice with Vegetation 36 Relationship of Ranges of Mice to Food, Temperature and Water 38 The Morphology and Pelage Color of the Mice as an Explanation of D i s t r i b u t i o n 40 Behavior of the Mice as a Cause of D i s t r i b u t i o n 41 Interaction Between Species as a Cause of D i s t r i b u t i o n 43 Interaction Between Species by Odor 45 Apparatus for Testing Recognition of Odor 45 Results of Tests with the Olfactometer 47 SUMMARY 50 v i . APPENDIX Table I . Measurement d a t a p l o t t e d i n bar diagrams ( i n nuns.). 52 Table I I . " t " v a l u e s c a l c u l a t e d i n comparisons o f body p a r t s . 54-T a b l e I I I . Data p l o t t e d i n bar diagrams of i n d i c e s . 56 Table IV. B r e e d i n g data. 57 T a b l e V. R e s u l t s of odor d e s c r i m i n a t i o n experiments. 58 LITERATURE CITED 59 LIST OF FIGURES v i i . F i g . f o l l o w i n g page 1. Measurements Made 13 2(a). Histograms of weights of P. 1. noveboracensis and .P. m. g r a c i l i s by sex and age. 19 2(b). Bar diagrams o f weights of P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. 19 3 . Histograms of h i n d f o o t l e n g t h s o f P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. 19 4. Histograms of ear l e n g t h s of P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. 20 5(a). Bar diagrams of h i n d f o o t l e n g t h s of P. 1. .noveboracensis and P. m. g r a c i l i s by sex and age. 20 5(b). Bar diagrams of ear l e n g t h s of P. 1. noveboracensis .and P. m. g r a c i l i s by sex and age. 20 6(a). Histograms o f body l e n g t h s of P. 1. noveboracensls .and P. m. g r a c i l i s by sex and age. 20 6(b). Bar diagrams of body l e n g t h s o f P. 1. .noveboracensis and P. m. g r a c i l i s by sex and age. 20 7 ( a ) . Histograms o f t a i l l e n g t h s o f P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. 21 7(b). Bar diagrams of t a i l l e n g t h s of P. 1. noveboracensls and P. m. g r a c i l i s by sex and age. 21 8. Histograms of i n t e r p a r i e t a l widths of P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. 22 9. Histograms of i n t e r p a r i e t a l l e n g t h s of P. 1. noveboracensls and P. m. g r a c i l i s by sex and age. 22 1 0(a). Bar diagrams of i n t e r p a r i e t a l widths o f P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. 22 1 0(b). Bar diagrams of i n t e r p a r i e t a l l e n g t h s of P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. 22 11. Histograms of s k u l l l e n g t h s of P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. 23 12. Histograms of r o s t r a l l e n g t h s of P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. 23 1 3(a). Bar diagrams of s k u l l l e n g t h s of P. 1. noveboracensls and P. m. g r a c i l i s by sex and age. 23 v i i i . F i g . f o l l o w i n g page 1 3(b). Bar diagrams o f r o s t r a l l e n g t h s o f P. 1 . . ,noveboracensis and P. m. g r a c i l i s by sex and age. 23 14(a). Key to measurement polygons of P. 1 . noveboracensis -and P. m. g r a c i l i s . 26 14(b). Measurement polygons o f P. 1 . noveboracensis 26 .and P. m. g r a c i l i s . 1 5 . Histograms of the index ( I ) , E.L. X T.L. X I.L., f o r SK.L. P. 1 . noveboracensis and P. m. g r a c i l i s by sex and age. 29 16. Histograms o f the index ( I I ) , E.L. X T.L. X I.L., f o r R.L. P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. 29 1 7(a). Bar diagrams o f the index ( I ) , E.L. X T.L. X I.L., SK.L. f o r P. 1 . noveboracensis and P. m. g r a c i l i s by sex and age. 29 1 7(b). Bar diagrams o f the index ( I I ) , E.L. X T.L. X I.L., R.L. f o r P. 1 . noveboracensis and P. m. g r a c i l i s by sex and age. 29 18(a). Map of Counties and D i s t r i c t s o f s o u t h e a s t e r n O n t a r i o . 35 18(b). Range of P. 1 . noveboracensis i n s o u t h e a s t e r n .Ontario, taken p r i m a r i l y from R.O.M.Z. t r a p p i n g r e c o r d s . 35 18(c). Range of P. m. g r a c i l i s i n sout h e a s t e r n O n t a r i o taken p r i m a r i l y from R.O.M.Z. t r a p p i n g r e c o r d s . 35 1 9 . F o r e s t r e g i o n s of sout h e a s t e r n O n t a r i o ( a f t e r Rowe, 1 9 5 9 ) . 37 2 0 . Diagram o f odor d i s c r i m i n a t i o n apparatus (olfactometer)A6 i x . ACKNOWLEDGMENTS T h i s work has been made p o s s i b l e by the generous h e l p of many persons and i n s t i t u t i o n s . I am indebted to Dr. J . F. B e n d e l l who suggested the problem and gave g r e a t a s s i s t a n c e . Dr. I . MoT. Cowan p r o v i d e d the necessary f a c i l i t i e s f o r the housing and study o f the mice and gave generously o f h i s time and ad v i c e . Mr. S. M. Teeple s u p p l i e d mice from the K i n g s t o n area o f O n t a r i o . Dr. R. L. P e t e r s o n and Mr. S. Downing loaned specimens of P. m. g r a c i l i s from the R o y a l O n t a r i o Museum of Zoology and pe r m i t t e d me to use the f a c i l i t i e s o f the museum. Dr. D. A. Smith loaned specimens from areas of sympatry. Mr. R. Hepburn and the students and s t a f f at the W i l d l i f e S t a t i o n , A lgonquin Park, and Dr. S. Brown and the students a t Queen's B i o l o g i c a l S t a t i o n , Lake O p i n i c o n , p r o v i d e d h e l p and l o d g i n g . F i n a n c i a l support f o r the study was p r o v i d e d by the P r e s i d e n t ' s Committee on Research, U. B. C. I am g r a t e f u l to a l l o f the above people who a s s i s t e d and made t h i s study p o s s i b l e . My o n l y r e g r e t i s t h a t I cannot mention many others who a l s o c o n t r i b u t e d t o the success o f the study. THE IDENTIFICATION AND DISTRIBUTION OF TWO SPECIES OF PEROMYSCUS IN SOUTHEASTERN ONTARIO. 1. INTRODUCTION The aims of t h i s study were to f i n d differences between Peromyscus leucopus noveboracensis (Fischer) and Peromyscua  manlculatus g r a c i l i s (LeConte) to separate them accurately and to determine whether these differences could be used to explain t h e i r d i s t r i b u t i o n . P._m. g r a c i l i s and P. 1. noveboracensis are two species of mice of the Family Cricetidae that are extremely s i m i l a r i n appearance and often occur sympatrlcally (Rutter, 1951; Klein, 1959; Cameron, 1956; Connor, I960; Waters, I 9 6 0 ) . Confusion i n i d e n t i f i c a t i o n of manlculatus and leucopus has long been a topic 'of conversation and study (Downing, personal communication; Rutter, 1951; Waters, I960). M I s i d e n t i f i c a t i p n of these species extends throughout the area where they occur or are thought to occur. Waters (1962) c i t e s an example of m i s i d e n t l f i c a t i o n i n southern New England where H a l l and Kelson (1959) extended the range of P. m. g r a c i l i s into northeastern Connecticut on the basis of a single specimen. Waters has examined t h i s specimen and has concluded that i t i s not g r a c i l i s but rather a young adult P. 1. noveboracensis• The taxonomy of these two species i s further confused by the wide range of c h a r a c t e r i s t i c s that have been used to separate them. The mice are generally described as follows. Peromyscus manlculatus g r a c i l i s (LeConte). The deer mouse 2. Is found i n c o l d , moist p l a c e s , or deep, mostly c o n i f e r o u s woods (Osgood, 1909). I t i s of medium s i z e , with a t a i l l o n g e r than o r equal to the l e n g t h o f the body ( B u r t and Grossenheider, 1952). The pelage c o l o r i s f u l v o u s to cinnamon-brown on the s i d e s and g r e y i s h a c r o s s the shoulders and top of the head. The dark e r c o l o r e d d o r s a l s t r e a k i n most g r a c i l i s i s not d i s t i n c t or i s l a c k i n g i n the r e g i o n of the rump ( S t a n d f i e l d , I95O). The underparts and f e e t are white. The s h a r p l y b i c o l o r t a i l i s brownish above and white below and i s g e n e r a l l y thought of as b e i n g more densely h a i r e d than t h a t o f leucopus. The p a l a t i n e s l i t s are l o n g and n e a r l y p a r a l l e l - s i d e d . Many animals have p r e a u r i c u l a r white h a i r s (Osgood, 1909). Peromyscus leucopus noveboracensis ( F i s c h e r ) . The wood mouse p r e f e r s d r y e r , more open country or deciduous woods (Osgood, 1909). I t i s s i m i l a r i n s i z e and c o l o r to g r a c i l i s but the t a i l i s s h o r t e r than or equal to the body l e n g t h (Burt and Grossenheider, 1952). The darker d o r s a l s t r e a k extends to the base o f the t a i l ( S t a n d f l e l d , 1950). The t a i l i s l e s s d i s t i n c t l y b i c o l o r and more s p a r s e l y h a i r e d than that of g r a c i l i s . The p a l a t i n e s l i t s are narrower at the ends than i n the middle. No p r e a u r i c u l a r white h a i r s are p r e s e n t (Osgood, 1909). Workers have separated leucopus and g r a c i l i s i n a v a r i e t y o f ways. Osgood (1909, P. 43) found g r a c i l i s to be s i m i l a r t o leucopus except t h a t the b r a i n c a s e was narro;«;er, the n a s a l s were l o n g e r , the m a x i l l a r i e s l e s s b u l g i n g i n f r o n t o f the i n f r a -o r b i t a l foramen, the a n t e r i o r p a r t o f the zygomata was l i g h t e r , p a l a t i n e s l i t s were l o n g e r and more n e a r l y p a r a l l e l - s i d e d and 3 . the molar t e e t h were s m a l l e r . Rand (1945) r e l i e d mainly on s k u l l c h a r a c t e r s to separate leucopus from m a n i c u l a t u s . A c c o r d i n g to him, manlculatus was a mouse seven and o n e - h a l f inches long, w i t h a s l e n d e r rostrum and l o n g s t r a i g h t s l i t s i n the p a l a t e . Leucopus was seven i n c h e s l o n g and had a tapered rostrum and s h o r t e r , curved s l i t s i n the p a l a t e . B u r t (1948) s t a t e s t h a t g r a c i l i s d i f f e r s from leucopus i n t h a t the a n t e r i o r border of the zygomatic p l a t e does not cover the I n f r a o r b i t a l foramen when viewed from the s i d e . S t a n d f i e l d (1950) found t h a t the shape o f the p a l a t i n e s l i t s was a good means of s e p a r a t i n g a l l maniculatus from leucopus. In the former, the o u t e r s i d e s o f the foramina are p a r a l l e l to each other, c u r v i n g i n a b r u p t l y at t h e i r a n t e r i o r ends. I n the l a t t e r , there i s a g r a d u a l c u r v i n g i n of the s i d e s of the foramina. The methods of s e p a r a t i o n o f B u r t and S t a n d f i e l d are d i f f i c u l t to use because they are s u b j e c t i v e . B u r t and Grossenheider (1952) admit t h a t these mice are d i f f i c u l t to t e l l apart, but say t h a t they can be separated on the b a s i s of t h e i r t a i l l e n g t h s . Cameron (1956) says t h a t the t a i l l e n g t h of leucopus i s u s u a l l y l e s s than o n e - h a l f the t o t a l l e n g t h and t h a t manlculatus has a t a i l l e n g t h t h a t i s u s u a l l y g r e a t e r than one-half the t o t a l l e n g t h . Waters ( I 9 6 0 , pp. 33 -34) used a more e l a b o r a t e system of i d e n t i f y i n g these s p e c i e s . H i s method depends on a number of s k u l l c h a r a c t e r s . In manlculatus the tympanic b u l l a Is r e l a t i v e l y f l a t t e r and l o n g e r , the temporal p o r t i o n of the zygomatic arch i s more widely f l a r i n g and the m a x i l l a r y p o r t i o n l e s s w idely f l a r i n g , the sphenoids are f l a t t e r , and the p o s t c r a n i a l c u r v a t u r e i s g r e a t e r . I n leucopus, the s u p r a o c c i p i t a l r e g i o n i s more p r o t r u s i v e and the p a l a t i n e foramina have a more pronounced l a t e r a l curve. He concludes by s a y i n g t h a t , " R e l a t i v e l y few i n d i v i d u a l s c o u l d not be assigned to the c o r r e c t s p e c i e s on the b a s i s of these c r i t e r i a . " . T h i s same author achieved a s e p a r a t i o n of the s p e c i e s by graphing body l e n g t h t a i l -length a g a i n s t s k u l l l e n g t h zygomatic width R u t t e r ( p e r s o n a l , communication) uses a v a r i e t y of c h a r a c t e r s to separate the mice. These i n c l u d e "whiteness" of the neck r e g i o n , shape o f the a n t e r i o r p o r t i o n of the zygomatic a r c h when viewed from above, shape of the a n t e r i o r p a l a t i n e foramina, and p o s i t i o n of the p o s t e r i o r p a l a t i n e foramina w i t h r e s p e c t to the cheek t e e t h . In summary, a v a r i e t y o f methods have been used to separate leucopus and maniculatus• Most of the above are s u b j e c t i v e methods t h a t are d i f f i c u l t t o use. Some r e q u i r e e l a b o r a t e p r e p a r a t i o n o f the s k u l l b e f o r e they can be a p p l i e d . None of the methods c o n s i d e r e d completely separated the two p o p u l a t i o n s of mice used i n t h i s study. That so many d i f f e r e n t c h a r a c t e r s are used to i d e n t i f y the mice i n d i c a t e s the need f o r b e t t e r , more q u a n t i t a t i v e methods of s e p a r a t i o n i n order to end the apparent c o n f u s i o n . The s i m i l a r i t i e s between leucopus and maniculatus i n appearance, measurements, and r e p r o d u c t i v e b i o l o g y are so g r e a t t h a t they could e a s i l y be c o n s i d e r e d as two subspecies of one s p e c i e s . Both are s e a s o n a l l y p o l y e s t r o u s and breed from March or A p r i l to 5 . October or November (Burt, 1940; Jackson, 1 9 5 2 ; H a l l and Kelson, 1 9 5 9 ; Waters, I 9 6 0 ) . S v i h l a ( 1 9 3 2 ) found the g e s t a t i o n p e r i o d of leucopus to be 2 2 - 3 7 days and t h a t of manlculatus t o be 2 2 - 3 5 days. L i t t e r s i z e s o f both are approximately the same: leucopus ( y o u n g / l i t t e r ) : 4.09 ±.08, S v i h l a ( 1 9 3 2 ) ; 4 . 2 6 (range 2 - 6 ) , B u r t ( 1 9 4 0 ) ; 4 .14 ±.08, Jackson ( 1 9 5 2 ) ; 4 . 1 0 - 4 . 7 2 , Davis ( 1 9 5 6 ) ; 5 . 0 0 (range 3 - 7 ) , H a l l and K e l s o n ( 1 9 5 9 ) ; 5.17 ± .29 - 5 . 2 0 ± . 3 6 , B e n d e l l ( 1 9 5 9 ) ; 4 . 3 (range 1-8), Connor (I960), manlculatus ( y o u n g / l i t t e r ) : 4.04 ± . 0 3 , S v i h l a ( 1 9 3 2 ) ; 5 . 3 3 , Beer e t a l ( 1 9 5 7 ) ; 5 . 0 0 (range 1-8), H a l l and K e l s o n ( 1 9 5 9 ) ; 5.1 (range 3 - 7 ) , Connor ( i 9 6 0 ) . D e s p i t e these s i m i l a r i t i e s , leucopus and manlculatus are v a l i d s p e c i e s . They do not I n t e r b r e e d i n nature, even i n areas where they both occur. I n these areas they can s t i l l be t o l d a p a r t by experts ( H a l l and Kelson, 1 9 5 9 ) . B r e e d i n g experiments have shown t h a t they a l s o do not i n t e r b r e e d i n the l a b o r a t o r y ( D i c e , 1 9 3 1 , 1 9 3 3 , 1 9 3 7 a ; Waters, I960). B r e e d i n g Experiments A number of i n v e s t i g a t o r s ( i n c l u d i n g myself) have conducted i n t e r b r e e d i n g experiments i n the l a b o r a t o r y to t e s t the v a l i d i t y o f the two s p e c i e s . Dice ( 1 9 3 7 a ) found t h a t 1 2 subspecies of leucopus were l n t e r f e r t i l e In the l a b o r a t o r y and both male and female h y b r i d s were a l s o f e r t i l e . T h i s same author ( 1 9 3 1 , 1 9 3 3 ) found t h a t no o f f s p r i n g r e s u l t e d from 6 9 attempted h y b r i d i z a t i o n s of v a r i o u s s p e c i e s of leucopus and maniculatus. A l l g r a c i l i s X noveboracensis h y b r i d i z a t i o n s were f a i l u r e s . Waters ( I 9 6 0 ) attempted to h y b r i d i z e f o u r noveboracensis with f o u r g r a c i l i s w i t h 6 . s i m i l a r r e s u l t s . He a l s o observed t h a t there had been no apparent sexual i n t e r e s t or a c t i v i t y between the mice of these p a i r s . As a c o n t r o l , Waters cro s s e d 10 p a i r s o f noveboracensis. F i v e F]_ and one F 2 l i t t e r s r e s u l t e d . My own experiments w i l l be d i s c u s s e d l a t e r . Other S p e c i e s o f Peromyscus i n Southeastern O n t a r i o The o n l y other form o f Peromyscus i n s o u t h e a s t e r n O n t a r i o i s P. m. b a l r d l l (Hoy and K e n n i c o t t ) , the p r a i r i e deer mouse. Saunders (1907, 1908, 1913) r e c o r d e d the eastward movement of the p r a i r i e deer mouse as i t began i t s range e x t e n s i o n a c r o s s southern O n t a r i o . As i t i s s m a l l e r i n s i z e than the oth e r two forms and t h e r e f o r e r e a d i l y separated from them, I s h a l l not co n s i d e r t h i s mouse i n the pr e s e n t study. D i s t r i b u t i o n of leucopus and maniculatus While leucopus and maniculatus are e x c e e d i n g l y s i m i l a r i n many r e s p e c t s , they have d i f f e r e n t ranges. The search f o r d i f f e r e n c e s between the s p e c i e s was not onl y to separate them but t o f i n d how the d i s t r i b u t i o n o f each form was determined. Many accounts have been g i v e n o f the d i s t r i b u t i o n o f these mice. Osgood's (1909) d i s t r i b u t i o n maps o f g r a c i l i s and noveboracensis i n O n t a r i o show that g r a c i l i s occupies the area e a s t o f the Great Lakes up to the border o f Quebec, while noveboracensis i s r e s t r i c t e d to southern O n t a r i o . H a l l and Kelson (1959) g i v e d i s t r i b u t i o n maps of both s p e c i e s . The g e n e r a l d i s t r i b u t i o n o f leucopus and maniculatus i n d i c a t e s t h a t they occupy separate ranges. They meet i n an are a o f sympatry which extends.from approximately 44°45l to 7 . approximately 4 5 0 3 0 ' (Rutter, 1951). Osgood (1909), and Cross and Dymond ( 1929) noted a cor r e l a t i o n between vegetation and d i s t r i b u t i o n In these species. K l e i n (I960) commented on t h i s tendency toward ecological separation of leucopus and manlculatus. He could not f i n d reasons for t h i s separation but suggested that i t was perhaps due to differences i n microclimate. Many attempts have been made to correlate other factors such as differences i n food preference, temperature tolerance, and water requirement with the d i s t r i b u t i o n of the two species. Kinds of food eaten by the mice were reported by Dice ( 1 9 2 2 ) , Cogshall ( 1 9 2 8 ) , Burt ( 1 9 4 0 ) , Hamilton (1941), Jackson ( 1 9 5 2 ) , Cameron ( 1 9 5 6 ) , Williams ( 1 9 5 9 ) , Connor (1960), Getz (1961), and Howard (1961). Foods eaten Included various seeds, nuts, insects, araehnlds, f r u i t s , fungi, green vegetation, roots, and molluscs. Being omnivorous, the mice apparently eat whatever foods are most abundant and easy to obtain. No differences i n food preference are known for g r a c i l i s and noveboracensis ( K l e i n , I960). Thus food does not appear to be a factor governing the d i s t r i b u t i o n of these mice. Sealander (1951) suggested that the northward d i s t r i b u t i o n of small mammals might be l i m i t e d by winter temperature. K l e i n (1959) f e l t that the occurrence of maniculatus at higher al t i t u d e s than leucopus indicated that temperature play-s a great ro l e i n t h e i r d i s t r i b u t i o n . He also suggested (I960) that differences i n s o i l temperature might also be a factor. Howard ( 1 9 5 1 ) ,and Eskridge and Udall ( 1955) found that both species 8. could withstand freezing temperatures provided that s u f f i c i e n t food was available. Lindeborg ( 1952) found that leucopus and maniculatus have a si m i l a r reaction to l i m i t e d amounts of water. Neither could survive on 0 . 2 cc./day and at 0 . 4 cc./day, each l o s t weight. Chenoweth ( 1917) concluded that although leucopus seemed to be able to adapt to d i f f e r e n t moist environments, evaporation was an important factor i n i t s d i s t r i b u t i o n . When leucopus was kept on a r e s t r i c t e d water d i e t (Chew, 1951)» most water conservation was effected by a reduction i n urine volume. Evaporation was reduced and became the greatest path of water l o s s . An average of 3 9 $ of the amount of water normally drunk ad l i b i t u m was required i n order to maintain normal weight. I f l e s s water than t h i s was given, the food intake decreased and the animal l o s t weight. Dice ( 1922) found that water was not the factor l i m i t i n g leucopus and b a i r d l i to t h e i r respective environments. Klein's ( 1959) study of water intake of leucopus and g r a c i l i s showed that both used about the same amount of water: leucopus: 0 . 4 3 cc./gram body weight or 7 . 6 c c . / i n d i v i d u a l / day; g r a c i l i s : 0.42 cc./gram body weight or 7 . 4 c c . / i n d i v i d u a l / day. Recently I obtained a copy of the trapping records of Peromyscus i n Ontario from the Royal Ontario Museum of Zoology. I s h a l l use these data i n preference to a l l other because they are the most up to date records of the two species i n south-eastern Ontario. In addition, I correlate d i s t r i b u t i o n with 9 . Rowe's ( 1959) new desc r i p t i o n of the vegetation of Ontario. Numerous studies have shown that the form of an animal i s related to i t s d i s t r i b u t i o n (Palmgren, 1 9 3 2 ; Robbins, 1 9 3 2 ; Lack, 1 9 4 4 ; Horner, 1 9 5 4 ) . In t h i s study I s h a l l t r y to correlate the differences I f i n d between the species i n form and color with t h e i r d i s t r i b u t i o 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 of some sort might explain the d i s t r i b u t i o n and also the f a i l u r e of the two species to i n t e r -breed In the laboratory. Studies of the behavior and i n t e r a c t i o n of these species with each other or with other animals have been made by Dice ( 1 9 2 2 ) , S v i h l a ( 1 9 3 2 ) , King ( 1 9 5 8 ) , Foster ( 1 9 5 9 ) , K l e i n ( 1 9 5 9 ) , and Sheppe ( 1 9 6 1 ) . Sheppe concluded that the r e s t r i c t e d habitat d i s t r i b u t i o n of P. oreas and P. manlculatus In t h e i r zone of sympatry may r e s u l t i n part from i n t e r s p e c i f i c competition. Since mammals operate i n a world of odor (as opposed to the highly v i s u a l world of b i r d s ) , and since these p a r t i c u l a r mammals are nocturnal, i t seemed possible that leucopus and manlculatus might react to one another by smell. The avoidance of one species by the other might explain t h e i r d i s t r i b u t i o n and sexual i s o l a t i o n . Therefore, experiments were conducted to tes t the reactions of each species to i t s own and to the other species' odor. Summary of the Problem Two very s i m i l a r species of Peromyscus, P. 1 . noveboracensis and P. m. g r a c i l i s , occur i n southeastern Ontario. These species occupy d i f f e r e n t ranges but occur sympatrlcally where these 10. ranges o v e r l a p . The problem Is to f i n d d i f f e r e n c e s between the s p e c i e s i n o r d e r to separate them and to determine whether these d i f f e r e n c e s c o u l d be used to e x p l a i n t h e i r d i s t r i b u t i o n . 1 1 . THE TAXONOMIC SEPARATION OF PEROMYSCUS LEUCOPUS NOVEBORACENSIS AND PEROMYSCUS MANICULATUS GRACILIS MATERIALS AND METHODS Co l l e c t i o n of Specimens Most of the specimens used i n t h i s study came from two areas i n Ontario, one near Kingston and the other near Lake of Two Rivers, Algonquin Park. According to maps of Osgood ( 1 9 0 9 ) , and Downing ( 1 9 4 8 ) , only P. 1 . noveboracensis occurs i n the area around Kingston. The mice from t h i s area f i t the description f o r the species (Osgood, 1 9 0 9 ; Burt, 1 9 4 0 ; Waters, I 9 6 0 ) . Extensive c o l l e c t i n g of mice near Lake of Two Rivers ( W i l d l i f e Research Station, Lake Sasajewan) has yielded only P. m. g r a c i l i s (with the exception of a single specimen from the Joe Lake area, Algonquin Park, t e n t a t i v e l y i d e n t i f i e d as P. 1 . noveboracensis (Downing, personal communication)). Mice from t h i s area f i t the description for the species (Osgood, 1 9 0 9 ; Burt and Grossenhelder, 1 9 5 2 ; Waters, I 9 6 0 ) . The specimens of leucopus were trapped by Dr. J . F. Bendell and Mr. S. M. Teeple during 1 9 5 6 , 1958, and 1 9 5 9 , and sent to me i n 10$ formalin. This group of 120 adult, subadult, and juvenile mice consisted of 59 males and 61 females. I also received 17 l i v e specimens of leucopus ( 12 males and 5 females) early i n 1961 from Mr. S. M. Teeple. I co l l e c t e d 157 adult and subadult P. m. g r a c i l i s ( 6 7 males and 90 females) near Lake of Two Rivers, Algonquin Park. C o l l e c t i n g was done by snap-trapping early i n the f a l l of 1 9 6 1 . . 12. These animals were aged, sexed, weighed, and measured shortly-a f t e r trapping and were transported to the University of B r i t i s h Columbia In 10$ formalin. Seven l i v e g r a c i l i s (5 males and 2 females) were brought back to the University of B r i t i s h Columbia from Algonquin Park. Specimens of P. m. g r a c i l i s were obtained from the Royal Ontario Museum of Zoology through the kindness of Dr. R. L. Peterson and Mr. S. Downing. These included 61 male and 39 female mice trapped i n Algonquin Park. A l l specimens mentioned thus f a r were trapped i n areas reported to contain only P. 1. noveboracensls or P. m. g r a c i l i s . Dr. D. A. Smith sent a c o l l e c t i o n of 12 mice (6 males and 6 females) from areas near Cloyne, Frontenac County and Calabogie, Renfrew County. In these areas, the mice occur sympatrically and are therefore more d i f f i c u l t to separate. Preparation of Specimens A l l mice except those from the Royal Ontario iviuseum of Zoology and from Dr. D. A. Smith were prepared f o r study i n the following way. Animals i n formalin were rinsed with water and damp dried. Freshly k i l l e d animals were used without further' preparation. The animals were aged, sexed, and weighed. Specimens of leucopus were weighed with stomach contents removed, but time l i m i t a t i o n prevented a si m i l a r procedure to be followed for maniculatus. Body, t a i l , ear, and hind foot lengths were measured. The baculum was removed, mounted immediately on a glass s l i d e under a piece of cel l u l o s e tape or embedded i n clear glue, and measured. The s k u l l was removed, p a r t i a l l y cleaned, 13. and s k u l l length, r o s t r a l length, I n t e r p a r i e t a l length, and Int e r p a r i e t a l width were measured. The shape of the anterior palatine foramina was noted. F i n a l l y , the pelage was examined for color and texture. Only s k u l l measurements were made on specimens from the Royal Ontario Museum of Zoology and from Dr. D. A. Smith. Body measurements of these mice were taken d i r e c t l y from accompanying museum la b e l s . Features Selected f o r Measurement Features were selected on the basis of ease of measurement and use by other workers i n the separation of the species (Osgood, 1909; Dice, 1932, 1937(b); B l a i r , 1941; Burt and Grossenheider, 1952). These were: s k u l l length, r o s t r a l length, ear length, body length, t a i l length, baculum length, and baculum width. I also measured I n t e r p a r i e t a l length and width. I n t e r p a r i e t a l length and width have not been used extensively fo r comparison of Peromyscus, but examination of the s k u l l s of both species l e d me to believe that these measurements (e s p e c i a l l y i n t e r p a r i e t a l length) d i f f e r e d consistently between the species. The following measurements were taken: Total S k u l l Length ( F i g . 1(a)): The longest length of the s k u l l ; from the anterior edge of the nasals to the posterior edge of the o c c i p i t a l s . Rostral Length ( F i g . 1(b)): The distance from the anterior edge of the upper i n c i s o r to the anterior edge of the f i r s t upper premolar. Hind Foot Length ( F i g . 1(c)): The distance from the back of the heel to the end of the longest claw. < A » < G H » F i g u r e 1 . MEASUREMENTS MADE A . T O T A L S K U L L L E N G T H B. R O S T R A L L E N G T H C . HIND F O O T L E N G T H D. E A R L E N G T H E . I N T E R P A R I E T A L WIDTH F. INTERPARIETAL L E N G T H G . B O D Y L E N G T H H. T A I L L E N G T H 14. Ear Length ( F i g . 1(d)): The distance from the bottom of the notch of the ear to the t i p of the ear. I n t e r p a r i e t a l Width ( F i g . 1(e)): The shortest distance across the i n t e r p a r i e t a l bone, taken at the point where the mid-sagittal suture meets the i n t e r p a r i e t a l bone. I n t e r p a r i e t a l Length ( F i g . 1 ( f ) ) : The greatest length of the i n t e r p a r i e t a l bone. Body Length ( F i g . 1(g)) and T a l l Length ( F i g . 1(h)): The body and t a i l lengths were obtained by placing the relaxed animal on a piece of cardboard on which a straight l i n e had been ruled. The nose, base of the t a i l and t i p of the t a l l were placed on the l i n e . Pins were placed at the t i p of the nose, base of the t a i l , and end of the t a i l (excluding the t a l l t i p h a i r s ) . The mouse was then removed and the distance between the pins along the straight l i n e was measured. Weight: The mice were weighed to the nearest tenth of a gram. Leucopus specimens were weighed with stomach contents removed. Shortage of time did not permit maniculatus to be weighed with stomach contents taken out. Baculum Length: The greatest length of the baculum (os penis). Baculum Width: The greatest width of the basal portion of the baculum. These l a s t two measurements are not shown i n F i g . 1 because they are applicable only to male animals. 1 5 . Number of Animals Used The mice were aged by pelage color ( C o l l i n s , 1923) and r e l a t i v e amount of tooth wear (Hooper, 1 9 5 7 ) . Of the 157 maniculatus that I trapped, 25 could not be assigned with certainty to either the adult or subadult category and f o r t h i s reason were not used. Of the remaining 132 specimens, 31 animals were lacking one or more of the measurements taken (usually because of a broken s k u l l or mutilated t a i l ) . These animals also were not used i n the present study. Thus, out of 157 specimens of manlculatus, a t o t a l of 101 specimens were used f o r a l l comparisons. Of the 120 leucopus, 3 animals were subadults and 2 were juveniles. These numbers were hardly s u f f i c i e n t to use i n a comparative study and were therefore omitted. Of the remaining 115 animals, 4-7 were lacking one or more measurement. Thus a t o t a l of 68 leucopus were used for a l l comparisons except f o r the indices where an additional 24 animals were included. Methods of Data Analysis Histograms and bar diagrams were plotted of a l l measurements (except baculum length and width) and weights taken. Each bar diagram shows the t o t a l range of measurements by a horizontal l i n e , the mean by a v e r t i c a l l i n e , one standard deviation on each side of the mean by an "open" rectangle, and two standard errors on each side of the mean by a " s o l i d " rectangle. The " t " test f o r comparisons of groups with unequal numbers of samples i n each (Larkin, personal communication), at the 5$ l e v e l of significance was used to measure differences between 16. t h e s p e c i e s i n the s i z e o f p a r t s . P a r t s t e s t e d i n c l u d e d e a r l e n g t h , body l e n g t h , t a i l l e n g t h , s k u l l l e n g t h , r o s t r a l l e n g t h , and i n t e r p a r i e t a l l e n g t h . The " t " v a l u e was a l s o used t o e x p r e s s the amount o f d i f f e r e n c e between p a r t s o f each s p e c i e s . From the s t u d y o f the form o f l e u c o p u s and m a n i c u l a t u s , i t became c l e a r t h a t no one p a r t s e p a r a t e d t h e a n i m a l s w e l l . However, each s p e c i e s showed a group o f c h a r a c t e r s t h a t tended t o d i f f e r between the s p e c i e s . To show t h e s e t e n d e n c i e s , measurement p o l y g o n s o f a d u l t a n i m a l s o f each sex were c o n s t r u c t e d . These p o l y g o n s c o n s i s t e d o f 8 axes on w h i c h th e average measure-ments ( i n mm.) o f 8 body p a r t s were p l o t t e d . E a c h p o l y g o n r e p r e s e n t s an average a n i m a l o f each sex and s p e c i e s o f mouse. E x p e r i m e n t s i n I n t e r b r e e d i n g B r e e d i n g e x p e r i m e n t s between l e u c o p u s and m a n i c u l a t u s were conducted. S i x mixed p a i r s o f l e u c o p u s and m a n i c u l a t u s , 3 p a i r s o f l e u c o p u s , and 4 p a i r s o f m a n i c u l a t u s were k e p t t o g e t h e r f o r p e r i o d s r a n g i n g from 71 days t o o v e r a y e a r . The a n i m a l s were housed i n 2 g a l l o n g l a s s a q u a r i a and were p r o v i d e d w i t h sawdust and c o t t o n b a t t i n g f o r n e s t m a t e r i a l . Food was i n p e l l e t f o rm (U. B. C. r a t i o n #6-61) and water was p r o v i d e d i n g r a v i t y water b o t t l e s i n s e r t e d t h r o u g h the w i r e t o p s o f the a q u a r i a . F a c t o r s I n f l u e n c i n g D i s t r i b u t i o n C o r r e l a t i o n was made between the d i s t r i b u t i o n o f l e u c o p u s and m a n i c u l a t u s and v e g e t a t i o n , t emperature t o l e r a n c e , f o o d p r e f e r e n c e , w a t e r r e q u i r e m e n t , morphology, c o l o r o f p e l a g e , and b e h a v i o r . T h i s was done from r e c e n t i n f o r m a t i o n i n the l i t e r a t u r e . 17. D e t a i l s o f the method of a n a l y s i s w i l l be presented l a t e r . Experiments i n Odor D i s c r i m i n a t i o n Experiments were conducted to t e s t odor d i s c r i m i n a t i o n between leucopus and manlculatus. For t h i s p a r t of the work, I designed and c o n s t r u c t e d an odor d i s c r i m i n a t i o n apparatus ( o l f a c t o m e t e r ) . D e t a i l s o f the method of a n a l y s i s of odor d i s c r i m i n a t i o n between the mice w i l l be presented i n a l a t e r s e c t i o n on o l f a c t i o n . 18. THE SEARCH FOR GOOD CHARACTERS TO SEPARATE THE SPECIES RESULTS AND CONCLUSIONSr The measurements of P. 1 . noveboracensis and P. m. g r a c i l i s were compared to f i n d those useful i n the separation of the species. To do t h i s , the measurements of a part were compared for each sex and available ages of a species. The measurements were compared on the same scale by histograms and bar diagrams (Dice and Leraas, 1936, as modified by Hubbs and Hubbs, 1 9 5 3 ) . These data are presented f o r weight i n F i g . 2(a,b); hind foot length i n F i g . 3 and F i g . 5(a); ear length i n F i g . 4 and F i g . 5(b); body length In F i g . 6(a,b); t a i l length i n F i g . 7(a,b); i n t e r p a r i e t a l width i n F i g . 8 and F i g . 1 0(a); I n t e r p a r i e t a l length i n F i g . 9 and F i g . 1 0(b); s k u l l length i n F i g . 11 and F i g . 1 3(a); and r o s t r a l length i n F i g . 12 and F i g . 1 3(b). Figures to the l e f t of each histogram and bar diagram indicate the number of animals being compared. Letters to the r i g h t of each histogram and bar diagram indicate the species, sex, and age of the animals used (L P. 1 . noveboracensis, M=P. m. g r a c i l i s , cf^male, 9=female, A «adult, S = subadult). Data plotted i n the bar diagrams are presented i n the Appendix (Table I ) . The e f f e c t of formalin preservation on length of body parts was investigated by Lanko ( I 9 6 0 ) . This preliminary study found no s i g n i f i c a n t differences between measurements taken before and a f t e r immersion for 30 days i n 10$ formalin. Therefore, the use of preserved material would not a f f e c t any comparisons made with mice that had been measured when freshly k i l l e d . 19-Weight The weights of leucopus and maniculatus were compared. Leucopus tends to be h e a v i e r than maniculatus. Although leucopus specimens were weighed minus stomach contents, t h e i r weights o v e r l a p and even exceed those o f maniculatus. Examination of F i g . 2(a,b) shows t h a t weight g i v e s no c l e a r s e p a r a t i o n o f leucopus and maniculatus. The weights of a d u l t male and female leucopus were not s i g n i f i c a n t l y d i f f e r e n t . The same was t r u e f o r the weights o f a d u l t male and female maniculatus and subadult male and female maniculatus. A d u l t leucopus and a d u l t maniculatus weights d i d not d i f f e r s i g n i f i c a n t l y . Weights of subadult maniculatus d i f f e r e d more from those of a d u l t leucopus than they d i d from those of a d u l t maniculatus. Hind f o o t l e n g t h Hind f o o t l e n g t h s have been used to separate s p e c i e s of Peromyscus. McCarley ( 1954) found h i n d f o o t l e n g t h to be the b e s t c h a r a c t e r to separate P. leucopus and P. gossypinus. Examination o f F i g s . 3 and 5(a) shows t h a t i t s u s e f u l n e s s i n s e p a r a t i n g P. 1. noveboracensis and P. m. g r a c i l i s i s l i m i t e d . A d u l t male and female leucopus do not d i f f e r s i g n i f i c a n t l y i n the l e n g t h of h i n d f o o t . Male a d u l t maniculatus have a s l i g h t l y l o n g e r , though not s i g n i f i c a n t l y l o n ger, h i n d f o o t than a d u l t female maniculatus. The ranges o f h i n d f o o t l e n g t h o f subadult male and female maniculatus were the same and d i d not d i f f e r s i g n i f i c a n t l y from the h i n d f o o t l e n g t h s o f a d u l t maniculatus. Some p a r t s (eg. body length) o f subadult maniculatus are s m a l l e r than those of the a d u l t , o t h e r s are not. For example, subadult Figure 2(a). Histograms of weights of P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. Figures to the l e f t of each histogram indicate the number of animals being compared. Letters to the r i g h t of each histogram indicate the species and age of the animals being compared. L = P. 1. noveboracensis M = P. m. g r a c i l i s A = Adult S = Subadult (This legend w i l l be used i n a l l histograms) 35 • • I 33 I 22 31 • I 22 J l 26 L. d (A) I . . L- 9 (A) I M. d" (A) M. £ (A) • M. d (S) M . 9 CS) UJ CD 68 53 48 L. d*9 CA) M. C/9 (A) M. d"9 (S) IO J I I I 15 20 25 30 F i g u r e 2 ( a ) . WEIGHT (GMS.) Figure 2(b). Bar diagrams of weights of P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. The t o t a l range of measurements i s shown by a horizontal l i n e , the mean by a v e r t i c a l l i n e , one standard deviation on each side of the mean by an "open" rectangle, and two standard errors on each side of the mean by a " s o l i d " rectangle. Figures to the l e f t of each bar diagram indicate the number of animals being compared. Letters to the r i g h t of each bar diagram indicate the species and age of the animals being compared. L = P. 1. noveboracensis M = P. m. g r a c i l i s A = Adult S = Subadult (This legend w i l l be used i n a l l bar diagrams) 33 »-22 »-31 i -22 •-26 »" n , M. (S) M. 9 (S) L. 9 (A) . M. d (A) 3 , M. 9 (A) 14 16 (8 2 0 2 2 2 4 2 6 2 8 3 0 F i g u r e 2 ( b ) . W E I G H T (GMS.) F i g u r e 3. Histograms of h i n d f o o t l e n g t h s o f P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. o-o-35 (A* 3 3 • (A) 2 2 • • I I • • • • M . C / ( A ) 3 1 • M . O (A) 2 2 • • M . O * ( S ) 6 8 2 5 J 2 0 -15-io-iiki.L I I L. 0 * 0 ^ (A) I O I H H I W M . cfo I I I I I I .1. ' I _l l_ 1 8 1 9 2 0 2 1 2 2 2 3 F i g u r e 3. HIND FOOT LENGTH ( M M . ) 20. h i n d f o o t l e n g t h s are the same as those of the a d u l t s . Perhaps the e a r l y attainment o f a d u l t s i z e i s necessary f o r adeptness i n c l i m b i n g or r u n n i n g . Ear l e n g t h E a r l e n g t h has been used as an a i d t o s e p a r a t i n g these s p e c i e s . Cameron (1956) p o i n t e d out t h a t leucopus has s h o r t e r ears than manlculatus. My data ( F i g s . 4 and 5(h)), show t h a t leucopus does have s h o r t e r ears and t h a t they are s i g n i f i c a n t l y s h o r t e r than those of manlculatus. The ear l e n g t h s o f a d u l t male and female leucopus do not d i f f e r s i g n i f i c a n t l y from each other. N e i t h e r do those o f a d u l t male and female maniculatus and subadult male and female maniculatus. E a r l e n g t h s o f sub-a d u l t maniculatus do not d i f f e r s i g n i f i c a n t l y from those of a d u l t maniculatus. Hence f u l l ear l e n g t h i s a t t a i n e d e a r l y i n l i f e . Perhaps the e a r l y attainment of a d u l t ear l e n g t h , l i k e h i n d f o o t l e n g t h has some adaptive s i g n i f i c a n c e . E a r l e n g t h was the most h i g h l y s i g n i f i c a n t l y d i f f e r e n t c h a r a c t e r found and most n e a r l y separated these s p e c i e s of mice. Body l e n g t h Body l e n g t h s were compared to assess t h e i r u s e f u l n e s s i n s e p a r a t i n g the two s p e c i e s . Leucopus tends to have a s h o r t e r body l e n g t h than manlculatus. No s i g n i f i c a n t d i f f e r e n c e s were found between male and female a d u l t s and male and female subadults o f e i t h e r s p e c i e s . Body l e n g t h s of subadult maniculatus were s i g n i f i c a n t l y d i f f e r e n t from those of a d u l t maniculatus. S i n c e a d u l t body l e n g t h i s not a t t a i n e d by subadult animals, i t may Figure 4. Histograms of ear lengths of P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. 3 5 ( A ) 3 3 I • mM H I I k l i • L. Q ( A ) 2 2 • • • • • • • • M . C ( A ) 3 1 • M M • M M I I • M . C; ( A ) 2 2 • 1 1 1 1 1 • " M . d ( S ) M . C) ( S ) 6 8 I I k J I H l I H J k I L. d*<J ( A ) 1.. M . IOI ( A . S ) I I i i i i i t i i i i i 1 5 16 1 7 1 8 1 9 2 0 21 pisure 4 . EAR L E N G T H ( M M . ) F i g u r e 5 ( a ) . Bar diagrams of h i n d f o o t l e n g t h s o f P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. F i g u r e 5 ( b ) . Bar diagrams o f ear l e n g t h s o f P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. 35 - i L . Cf (A") 33 »- L . 9 (A) 2 2 -i M . O" (A') 31 22 • 2 6 » 18 19 2 0 21 2 2 2 3 F i g u r e 5(a). HIND F O O T LENGTH ( M M . ) 35 i 1 I . L . Cf (A^ . M. Cf ( A ) • M. 9 ( A ) < M . Cf ( S ) < M. 9 (S) I I I I I I I t 15 16 17 18 19 2 0 21 22 F i g u r e 5(b). EAR L E N G T H ( M M . ) F i g u r e 6 ( a ) . Histograms of body l e n g t h s o f P . 1. noveboracensis and P . m. g r a c i l i s by sex and age. IO 5 C H 22 • • • 26 k . M. 9 ( A ) M. d ( S ) M . 9 ( S ) 66 53 I L . C/9 ( A ) M . (5*9 ( A ) 4 8 J — J I I M . C?9 ( S ) I I 7 0 8 0 9 0 IOO IIO F i g u r e 6(a). B O D Y L E N G T H (MM.) F i g u r e 6 ( b ) . Bar diagrams o f body l e n g t h s of P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. 35 i-3 3 H 3 , L9 CA) 2 2 M . C5 CA) 31 H H M . 9 CA) 2 2 H 3H M . c f CS) 2 6 h H M . 9 ( S ) 7 2 76 8 0 8 4 88 92 96 IOO 1 0 2 F i g u r e 6(b). B O D Y L E N G T H ( M M . ) 2 1 . not have as much adaptive significance as hind foot length or ear length. Although body lengths of adult leucopus and adult maniculatus were found to be s i g n i f i c a n t l y d i f f e r e n t , the wide range of measurement i n any one group ( f o r example, adult female maniculatus) make i t useless i n the separation of these species. T a i l length Investigators have often used t a i l length as an aid to separating these two species. Burt and G-rossenheider ( 1952) admit they are d i f f i c u l t to t e l l apart, but give the following as a f a i r l y good means of separation: P. 1 . n.: t a i l length shorter than 3 3/5 Inches ( 9 * 1 5 cms.); P. m. £.: t a i l length longer than 3 3/5 inches ( 9 . 1 5 cms.). This method, however, does not completely separate the mice used i n t h i s study. Of 120 noveborac ens1s, 9 have t a i l s longer than 9 . 1 5 cms.; of 157 g r a c i l i s (Algonquin Park), 136 have t a i l s shorter than 9*15 cms.; and of 100 g r a c i l i s (R.O.M.Z. loan), 78 have t a i l s shorter than 9 . 1 5 cms. Cameron ( 1956) says that the t a i l length of leucopus i s usually l e s s than one-half the t o t a l length and that manlculatus has a t a i l length that i s usually greater than one-half the t o t a l length. This method does not completely separate the specimens used here. Of 120 leucopus, 119 have a t a i l length le s s than one-half the t o t a l length; of 157 manlculatus (Algonquin Park), 69 have a t a i l length greater than one-half the t o t a l length; and of 100 maniculatus (R.O.M.Z. loan), 27 have a t a i l length greater than one-half the t o t a l length. Neither of the above methods i s substantiated by my data. F i g u r e 7(a). Histograms of t a i l l e n g t h s of P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. o--j < o-U. O or u a 2 i 5 O 5 O l 35 L. O" (A) 33 . -.1 22 L. J (A) M d (A) 31 M . 9 (A) 22 26 • M / Cf ( S ) M . 9 I S ) 68 L. 0 * 9 (A) 53 M. 0 * 9 (A) 48 • M. 6 9 (S) 60 70 eo 90 IOO no Figure 7 ( a ) . TAIL LENGTH (MM.) F i g u r e 7(b). Bar diagrams of t a l l l e n g t h s of P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. 35 h -i L.CJ (A) 33 t- H L. p (A) 22 »- M . (3 ( A ) 31 H M . 9 ( A ) 22 h * M . ( S ) 26 *• M . 9 ( S ) 6 0 6 5 7 0 7 5 8 0 8 5 9 0 95 IOO F i g u r e 7 ( b ) . T A I L L E N G T H ( M M . ) 22. Comparisons o f t a i l l e n g t h s of leucopus and maniculatus are shown i n F i g . 7(a,b). No s i g n i f i c a n t d i f f e r e n c e s i n t a i l l e n g t h were found "between the sexes o f each age group of each s p e c i e s . T a i l l e n g t h s o f a d u l t leucopus were s i g n i f i c a n t l y d i f f e r e n t from those o f a d u l t and subadult maniculatus. Subadult manlculatus tended t o have s h o r t e r t a i l s than a d u l t maniculatus. Although there was g r e a t o v e r l a p i n l e n g t h o f t a i l between leucopus and manlculatus. t h i s c h a r a c t e r appears to have some va l u e i n the s e p a r a t i o n of the two. I n t e r p a r i e t a l width I n t e r p a r i e t a l widths o f leucopus and maniculatus were examined f o r p o s s i b l e d i f f e r e n c e s . Graphic p r e s e n t a t i o n of i n t e r p a r i e t a l widths ( F i g s . 8 and 1 0 ( a ) ) , shows t h a t the measure-ments f o r b o t h s p e c i e s o v e r l a p too g r e a t l y f o r t h i s c h a r a c t e r to be o f taxonomic v a l u e . I n t e r p a r i e t a l l e n g t h The i n t e r p a r i e t a l l e n g t h has been used by H o f f m e i s t e r ( 1 9 5 1 ) » and Cockrum (1954-), f o r comparisons o f s p e c i e s of Peromyscus. These authors found t h a t the l e n g t h o f the i n t e r p a r i e t a l changes very l i t t l e w i t h age and t h a t i t does not d i f f e r between sexes. My data ( F i g s . 9 and 1 0(b)) show t h a t i t does not d i f f e r s i g n i f i -c a n t l y between the sexes and ages o f maniculatus and the sexes of leucopus. Leucopus has a s i g n i f i c a n t l y s h o r t e r i n t e r p a r i e t a l l e n g t h than manlculatus. I n t e r p a r i e t a l l e n g t h i s a good c h a r a c t e r f o r s e p a r a t i n g most animals of the two s p e c i e s . F i g u r e 8. Histograms of i n t e r p a r i e t a l widths P. 1. noveboracensis and P. m. g r a c i l i s sex and age. H-C CD CO m > m > O cn N U M B E R O F I N D I V I D U A L S O t n O c n O c n O c n 1 I * • i a . . f O 2 o» CO CO 2 +o > to 2 r > r > a H 2 2 09 +o 3 > F i g u r e 9. Histograms of i n t e r p a r i e t a l l e n g t h s of P. 1. noveboracensis and P. m. g r a c i l i s by-sex and age. 5 O O-5-O 5 to 5 < 9 ° > 5 Q Z u. O cc hi CQ I 5 z O 15 IO 5 O 35 33 6 8 L. O* ( A ) 22 31 22 26 L. 9 ( A ) L ..Liu .A M . O" ( A ) M . 9 ( A ) M . d ( S ) M . 9 ( S ) L . d"9 ( A ) lOI M . 0*9 C A , S ; 6.5 7.5 8.5 9.5 IQ5 F i g u r e 9 . INTERPARIETAL LENGTH ( M M . ) F i g u r e 1 0 ( a ) . Bar diagrams o f i n t e r p a r i e t a l widths o f P. 1. noveboracensis and P. m. g r a c i l i s by-sex and age. F i g u r e 10(b). Bar diagrams o f I n t e r p a r i e t a l l e n g t h s o f P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. 33 f 22 H 31 »• 2 2 >-2 6 y -i M . C f CA"J •i M . Cf (S) M. 9 ( S ) F i g . io (a ) . INTERPARIETAL WIDTH ( M M . ) 35 H 33 \-22 31 22 »-2 6 - i L . Cf CA) - L . 9 ( A ) -• M . Cf CA) M. 9 C A ) M. Cf CS) M . 9 C S ) 8 IO F i g . i o ( b ) . INTERPARIETAL L E N G T H CMM.) 23. S k u l l l e n g t h The l e n g t h s o f s k u l l s o f leucopus and maniculatus were examined f o r p o s s i b l e s p e c i f i c d i f f e r e n c e s ( F i g s . 11 and 13(a)). Leucopus has a s i g n i f i c a n t l y l o n g e r s k u l l than maniculatus, although there was g r e a t o v e r l a p of measurement. Subadult maniculatus tended to have s h o r t e r s k u l l s than a d u l t maniculatus. No s i g n i f i c a n t d i f f e r e n c e s i n s k u l l l e n g t h were found between the sexes o f a d u l t leucopus, a d u l t maniculatus, and subadult maniculatus. S k u l l l e n g t h i s u s e f u l i n the s e p a r a t i o n o f the mice. R o s t r a l l e n g t h Comparisons were made of r o s t r a l l e n g t h s o f leucopus and maniculatus ( F i g s . 12 and 13(b)). Leucopus tended to have a lo n g e r rostrum than maniculatus. Subadult maniculatus had a s h o r t e r rostrum than a d u l t maniculatus. No s i g n i f i c a n t d i f f e r -ences i n r o 3 t r a l l e n g t h were found between the sexes o f a d u l t leucopus, a d u l t maniculatus and subadult maniculatus. There was a g r e a t e r d i f f e r e n c e between the s p e c i e s i n s k u l l l e n g t h than i n r o s t r a l l e n g t h . T h i s c h a r a c t e r i s u s e f u l as an a i d to the s e p a r a t i o n o f the mice. Baculum l e n g t h The l e n g t h o f the baculum has been used by many authors to d i s t i n g u i s h between genera and s p e c i e s o f Peromyscus. B l a i r (194-2) found no marked q u a l i t a t i v e d i f f e r e n c e s between the b a c u l a of the maniculatus and leucopus s p e c i e s groups. Hooper (1958) r e p o r t e d the mean va l u e f o r baculum l e n g t h i n leucopus to be 9.0 mms. and i n maniculatus, 8.3 mms. B u r t (i960) questioned the F i g u r e 11. Histograms of s k u l l l e n g t h s o f P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. 35 a (A) 33 I • H a J k JL U • • L. 9 (A) • i i i J 22 • I I » M J M. d" (A) 31 • • J L H J I I I • • M. 9 (A) 22 • I • l a J h M. d" (S ) J . I b i — . 26 • • • Mm m mm • M . 9 ( S ) 68 •LMIJJ I • m L . <^ 9 (A ) 53 • I iJ JL»^ »M I MM m M. CJ9 (A) 4 8 • * • MM§ M . d 9 ( S ) 1 1 • 1 1 ' 1 ' ' 24 25 26 27 28 29 F i g u r e 11. SKULL LENGTH ( M M . ) F i g u r e 12. Histograms o f r o s t r a l l e n g t h s of P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. Figure 13(a). Bar diagrams of s k u l l lengths of P. 1. noveboracensis and P. m. g r a c i l i s by-sex and age. Figure 13(b). Bar diagrams of r o s t r a l lengths of P. 1. noveboracensis and P. m. g r a c i l i s by sex and age. 35 33 ' 22 -31 22 •-L . Cf (A ' ) - L. 9 (A) M. Cf (A') -t M. 9 (A) H M. Cf (S) M. 9 (S) ,1 2 4 25 26 2 7 28 29 Figure 13(a). S K U L L L E N G T H CMM.) 3 5 H 3 3 ' 2 2 i C 31 2 2 y-2 6 • C L. cf (A ) L. 9 (A) M. Cf (A) - M . O ( A ) M. Cf (S) H M. 9 CS) 7.4 7 8 8.2 8.6 9.0 9.4 9.8 Fig. 13(b). R O S T R A L L E N G T H (MM.) 24. taxonomic value of the baculum i n Peromyscus except for the separation of subgenera. He found the mean value f o r the length of the baculum of leucopus to be 9*5 mms. (range, 8.1-10.9 mms.), and of manlculatus to be 9 . 3 mms. (range, 8 . 7 - 9 » 8 mms.). These values are so s i m i l a r that t h e i r taxonomic usefulness i s n e g l i g i b l e . My data show that the lengths of the bacula of adult leucopus and maniculatus l i e i n the same size range. Leucopus averaged 8.9 mms. for 39 i n d i v i d u a l s (range, 5 . 3-11 . 3 mms.), and maniculatus averaged 8.1 mms. for 19 individuals (range, 6.0-10.0 mms.). Burt's statement (I960, P. 5 4 ) , that (the baculum length o f ) , "P. m. g r a c i l i s , f o r instance, Is well within the size range of leucopus." i s supported by my data. Baculum length i s not a good character f o r the separation of these species. In summary, graphic comparison Bhows that ear length and i n t e r p a r i e t a l length are the best characters to use i n the separation of P. 1. noveboracensis and P. m. g r a c i l i s . Neither of these measurements d i f f e r s i g n i f i c a n t l y between subadult and adult animals of the one species. T a i l length i s the next best character, followed by s k u l l length, r o s t r a l length, and hind foot length. Body length and i n t e r p a r i e t a l width overlap too greatly to be of any value. The Separation of leucopus and manlculatus using Morphological  Characters Comparison of parts of mice showed that some measurements d i f f e r e d more than others between species. To select the measurements most useful i n separating the species, " t " values 25. were calculated to show the degree of difference between measure-ments. No s i g n i f i c a n t differences, at the 5$ l e v e l , were found between the sexes of adult leucopus, adult maniculatus, and sub-adult maniculatus f o r a l l measurements compared. The parts compared between species, and t h e i r " t " values, are arranged i n a decreasing order of difference i n the following table: Table 1. Degree of difference between body parts of leucopus and maniculatus as shown by " t " values. - -Parts Compared " t " Value Ear length 51.436 T a i l length 49-352 I n t e r p a r i e t a l length 19.308 Body length 10.987 S k u l l length 7-326 Rostral length 3.722 The 1 11" values i n Table 1 are a l l s i g n i f i c a n t at the 5$ l e v e l and represent comparisons of body parts of adults of both sexes of leucopus with those of adults of both sexes of maniculatus. A complete summary of a l l " t " tests calculated i s given i n the Appendix (Table I I ) . Table 1 Indicates that leucopus and maniculatus are s i g n i f i c a n t l y d i f f e r e n t i n a l l comparisons for which " t " was calculated. The greatest divergence between the forms was i n those characters that possessed the largest " t " values. Length of ear possesses the largest " t " value but i s not s a t i s f a c t o r y , when used alone, to separate leucopus and maniculatus because the ranges of measurement f o r the two species overlap. Hence, while ear length separates the species s t a t i s t i c a l l y , i n practice, i t does not separate a l l the i n d i v i -duals. The above table also shows that these mice d i f f e r 26. s i g n i f i c a n t l y i n a number of c h a r a c t e r i s t i c s . I f these c h a r a c t e r i s t i c s are considered at the same time, a t o t a l difference may be seen between the species. This i s done i n F i g . l4(a,b), the measurement polygon. The measurement polygon expresses a number of c h a r a c t e r i s t i c s simultaneously. Each polygon i s a "picture" of an average animal, based on the mean values of 8 measurements. Examination of F i g . 14(b) reveals that there i s considerably more s i m i l a r i t y between polygons A and B and C and D than there i s between A and C or D or between B and C or D. The polygons c l e a r l y show that leucopus has a shorter average i n t e r p a r i e t a l width, ear length, body length, t a i l length, i n t e r p a r i e t a l length, and hind foot length, while i t s average s k u l l length and r o s t r a l length are longer than comparable average values for maniculatus. The Character Index f o r the Separation of leucopus and manlculatus While polygons express t o t a l average features, they are not a convenient way to separate the species. Also, I have no measure of the goodness of f i t of a species to a polygon. At the moment, a l l that can be said i s that a mouse i s either a leucopus or a manlculatus depending upon which polygon I t resembles most. Another way of making use of a number of tendencies i n each species to separate them i s by the use of the character index. The term "character index" was proposed by Hubbs and Whitlock (1929), who found the need f o r a simple mathematical expression of several d i f f e r e n t i a l features. These indices have been used successfully i n f i s h systematlcs f o r the separation of closely re 14(a). Key to measurement polygons of P. 1. noveboracensis and P. m. g r a c i l i s . One average measurement ( i n mms.) i s plo t t e d on each radius. E. L.= ear length B. L.= body length T. L.= t a i l length SK. Lr= s k u l l length R. L. = r o s t r a l length I. L. = i n t e r p a r i e t a l length H. F. L.= hind foot length I. ¥. = i n t e r p a r i e t a l width (This legend applies to Figure 14(b)) E.L R.L. Figure 14(a). M E A S U R E M E N T P O L Y G O N K E Y Figure 14(b). Measurement polygons of P. 1. noveboracensis and P. m. g r a c i l i s . Average measurements for each group of animals are plotted on each radius. A. = adult male P. 1. noveboracensis B. = adult female P. 1. noveboracensis 0.= adult male P. m. g r a c i l i s D^ =" adult female P. m. g r a c i l i s A . P L . N . cf ( A ) B . P L . N . 9 C A ) C R M . G . cf C A ) D . P M . G . 9 C A ) Figure 14(b). Measurement polygons of P. 1. n. and P. m. g. 2 7 . a l l i e d forms by Schultz ( 1 9 3 7 ) , Schultz and Welander ( 1 9 3 4 ) , Hubbs and Kuronuma ( 1 9 4 1 ) , and Hubbs et a l ( 1 9 4 3 ) . Davenport (1935) used simple indices to compare proportions of animals. Moreau and Southern ( 1957) used the index, tail/wing X 1 0 0 , to show geographical v a r i a t i o n i n shrikes. Cameron ( 1 9 5 8 ) found that the index, mean s k u l l height/mean r o s t r a l length, separated black bears of Newfoundland from those of the mainland. The pros and cons of using character indices f o r comparisons of species and subspecies of animals are discussed by Ginsburg (1939) and Hubbs et a l ( 1 9 4 3 ) . Hubbs et a l (P. 5 ) , strongly defend the use of character indices by saying that, "no arithmetic combination of characters, however, can bring out differences which do not exist, so long as we apply the i d e n t i c a l character-index formula to both types being compared.". They further state (P. 6 ) , that, "we have been informed by s t a t i s t i c i a n s that such values as standard deviation, standard error, and the l i k e may l e g i t i m a t e l y be computed for an array of the indices, provided that each of the combined characters presents i n i t s e l f an approximately normal frequency d i s t r i b u t i o n . " . The main c r i t i c i s m against the use of character indices i s concerned with the determination of species and subspecies (Ginsburg, 1 9 3 9 ) . This author points out that the degree of difference between in d i v i d u a l s of two populations depends on the characters selected and on the manipulations performed. These indices should not, therefore, be used to determine whether two populations are subspecies of one species or are separate species. Ginsburg*s c r i t i c i s m s are v a l i d and worthy of consideration. However, they do not apply to the problem I am t r y i n g to solve 28. with character indices. The animals used i n t h i s study are known to be separate species on the basis of t h e i r breeding biology and I wish only to be able to separate them by some quantitative rather than q u a l i t a t i v e method. Of the characters compared graphically and s t a t i s t i c a l l y , ear length, i n t e r p a r i e t a l length, and t a i l length were found to be the measurements d i f f e r i n g most between the two species. These characters were shorter i n leucopus than i n maniculatus. I f these three measurements were mult i p l i e d together for each i n d i v i d u a l of each species, the resultant indices f o r leucopus would be smaller than those f o r maniculatus. To further increase the difference between the two species, d i v i s i o n of these indices by another measurement that was longer i n leucopus than i n maniculatus would give even smaller indices f o r leucopus and comparably larger ones f o r maniculatus. Both r o s t r a l length and s k u l l length f i l l e d t h i s requirement and each was used as •part of a character index. The r e s u l t i n g indices were: I. ear length X t a l l length X I n t e r p a r i e t a l length s k u l l length II• ear length X t a l l length X i n t e r p a r i e t a l length r o s t r a l length Although each of these indices was found to completely separate leucopus and maniculatus, both are given here because specimens collected by snap trapping are often damaged and one of the necessary measurements, such as s k u l l length, might be unobtain-able. In t h i s example, index II could be used rather than index I. 2 9 . Tests of Indices I f an index i s to be of value, i t should be e a s i l y calculated and separate a l l ages and sexes of forms to which i t may be applied. The Indices were tested by c a l c u l a t i n g values f o r a l l animals used i n the study. Histograms and bar diagrams of the values f o r each species, sex, and age group were plotted ( F i g s i 15, 16, 17(a,b)). Also included i n the tests (but not graphed) were data f o r mice from the Royal Ontario Museum of Zoology and from Osgood ( 1 9 0 9 , pp. 260-61, 263-64). A summary of data p l o t t e d i n bar diagrams f o r each species, sex, and age group i s given i n the Appendix (Table I I I ) . The indices f o r each species were compared by " t " test and found s i g n i f i c a n t l y d i f f e r e n t at the 5$ l e v e l for mice from a l l areas. I t has already been shown that sex had no e f f e c t on measure-ments. Although subadult mice tend to have smaller parts, Figs. 1 5 , 16, and 17(a,b) show that age does not a f f e c t the values of the indices calculated for a l l age groups examined. Since the values of the indices are not affected by sex or age, data for each species can be combined. Oombined data of the indices are presented i n Table 2. Table 2. Means and ranges of combined data of the character indices of leucopus and maniculatus. Index I Index I I Species N Source Mean Range Mean Range leucopus 92 L. Opin., 3.41 2.57-4.09 10.45 7. 39-: 12 .50 Perth Rd. maniculatus 101 Alg. Park 5.62 4.26-7.14 17.16 12 .83--21.93 maniculatus 13 R.O.M.Z. 6.57 5.39-7.90 19 .85 16 .24. -22.77 leucopus 10 Osgood 3.49 maniculatus 10 Osgood 5.75 5.69-5.83 F i g u r e 15. Histograms of the index ( I ) , E.L. X T.L. X I.L.« f o r P. 1. noveboracensis SK.L. and P. m. g r a c i l i s by sex and age. E. L . = ear l e n g t h T. L. = t a l l l e n g t h I. L. = i n t e r p a r i e t a l l e n g t h SK. L.= s k u l l l e n g t h N U M B E R O F I N D I V I D U A L S F i g u r e 16. Histograms o f the index ( I I ) , E.L. X T.L. X I.L., f o r P. 1. noveboracensis R.L. and P. m. g r a c i l i s by sex and age. E. L *= ear l e n g t h T. L*= t a i l l e n g t h I . L.F I n t e r p a r i e t a l l e n g t h R. L.= r o s t r a l l e n g t h Figure 17(a). Bar diagrams of the index ( I ) , E.L. X T.L. X I.L., f o r P. 1. noveboracensis SK.L. and P. m. g r a c i l i s by sex and age. (Legend as i n Figure 15) Figure 17(b). Bar diagrams of the index ( I I ) , E.L. X T.L. X I.L., f o r P. 1. noveboracensis R.L. and P. m. g r a c i l i s by sex and age. (Legend as i n Figure 16) 4 6 •-4 6 *~-L. 0* CA) L. 9 ( A ) 22 *-31 ' — -22 i — — » M- Cf C A ) 1 M . 9 ( A ) M . Cf ( S ) 2 6 - M . 9 ( S ) • i i _| L 1 2 D 3.0 4.0 5.0 6.0 7.0 8.0 , . , K i r > r r v E.LX T L X I.L. F i g . 1 7 ( a ) . INDEX-4 6 i-4 6 ' 3 — i L. O* CA) — . L. 9 CA) 2 2 i c 31 ' • = 2 2 •-26 -t M. Cf (A) . M . 9 CA) ^ M. Cf CS) -I M . 9 Cs) I I I I I I I I 65 8 5 IQ5 125 145 165 I 8 [ 5 2 0 5 225 i M H C Y E.LX T L X I.L F i g . 1 7 ( b ) . INDEX* p |_ 3 0 . Table 2 shows that means and ranges of character indices calculated for leucopus d i f f e r from those calculated for manlculatus. 111" tests and bar diagrams ( F i g . 17(a,b) show that a l l leucopus indices d i f f e r s i g n i f i c a n t l y from a l l manlculatus indices. Hence, the character indices completely separate leucopus and manlculatus of a l l ages and sexes that were examined. A mouse with an index I of 2 . 5 7 - 4 . 0 9 i s leucopus and one with an index I of 4 . 2 6 - 7 - 9 0 i s maniculatus. A mouse with an index II of 7 .39-12 .50 i s leucopus and one with an index II of 12 .83-22.77 i s manlculatus. Although Osgood (1909) measured ear lengths from dried specimens, the values for indices calculated from h i s data f a l l within the ranges of each species index derived from my data. The shrinkage of pinnae i s apparently not s u f f i c i e n t to greatly a l t e r the value of the index. Test of the Indices on Mice From an Area of Sympatrv The indices worked to separate mice from areas and samples that were chosen to represent "good" leucopus and manlculatus. I f the mice are not good species, they might blend i n areas of sympatry. Also, i t i s i n areas of overlap of range that geography i s of no assistance i n the i d e n t i f i c a t i o n of a specimen. Thus, the f i n a l and perhaps most c r i t i c a l test of the indices was to apply them to mice caught i n the area of sympatry of leucopus and maniculatus i n Ontario. Twelve mice from areas of sympatry were sent to me by Dr. D. A. Smith of Garleton University, Ottawa. Almost a l l were captured two and one-half miles north of Cloyne, Frontenac 31. County. Two were captured f i v e miles northwest of Calabogie, Renfrew County. Calculation of indices I and I I for these mice completely separated them into two groups. Four specimens were c l e a r l y referable to leucopus (index I: range 3.35-3.93; index I I : range, 10.56-12.38) and 8 specimens were c l e a r l y referable to manlculatus (index I: 4.39-6.01; index I I : 13.36-18.61). This test again indicates that the Indices are v a l i d methods for the separation of P. 1. noveboracensis and P. m. g r a c i l i s i n southeastern Ontario. Summary of the Indices Indices have been shown to be v a l i d tools f o r separating closely related, d i f f i c u l t to separate species. Indices were formulated that completely separate P. 1. noveboracensis and P. m. g r a c i l i s on a quantitative basis. These indices are: I. ear length X t a l l length X I n t e r p a r i e t a l length s k u l l length I I . ear length X t a l l length X I n t e r p a r i e t a l length r o s t r a l length These indices completely separate the two species regardless of sex and age. For index I, values ranging from 2.57 to 4.09 are i n d i c a t i v e of leucopus, while values ranging from 4.26 to 7.90-are i n d i c a t i v e of manlculatus. For index I I , values ranging from 7.39 to 12.50 are i n d i c a t i v e of leucopus, while values ranging from 12.83 to 22.77 are i n d i c a t i v e of manlculatus. The indices are simple and easy to use quantitative methods for the separation of P. 1. noveboracens1s and P. m. g r a c i l i s . The indices separated noveboracensis and g r a c i l i s from areas of sympatry and areas of allopatry. 3 2 . R e s u l t s o f C r o s s b r e e d i n g C r o s s b r e e d i n g experiments between P. leucopus and P. maniculatus were attempted i n the l a b o r a t o r y . R e s u l t s of the experiments are summarized i n the Appendix (Table I V ) . Four o f the 17 l i v e leucopus r e c e i v e d e a r l y i n 1961 were p a i r e d w i t h l o c a l maniculatus (P. m. austerus, P. m. oreas, and P. m. spp. from Mandarte I s l a n d , B r i t i s h Columbia). These mice have been p a i r e d f o r over a year and have not l i t t e r e d . Two c o n t r o l p a i r s of leucopus produced a t o t a l of three l i t t e r s . One c o n t r o l p a i r o f each o f the above subspecies o f l o c a l maniculatus produced a t o t a l o f two l i t t e r s (P. m. oreas f a i l e d to b r e e d ) . Two mixed p a i r s (P. m. g.C? X P. 1. n . 9 ), (P. m. X P. 1. n.cf) o f mice were p l a c e d i n separate cages on February 17, 1962. The mice have been i n b r e e d i n g c o n d i t i o n b ut have not l i t t e r e d . One p a i r o f leucopus and one p a i r o f maniculatus were p l a c e d i n separate cages on the same date, i n the same room, to be used as c o n t r o l s . No l i t t e r s have r e s u l t e d from these p a i r s . The n e g a t i v e r e s u l t s o b t a i n e d by the attempted c r o s s b r e e d i n g of leucopus and maniculatus support those of Di c e (1931> 1 9 3 3 , 1937), and Waters (I960). The f a c t t h a t p a i r s o f leucopus and maniculatus, chosen at random from groups o f mice caught i n the same areas and kept i n s i m i l a r cages i n the same room, produced l i t t e r s , i n d i c a t e s t h a t something other than l a b o r a t o r y c o n d i t i o n s a p p a r e n t l y i n h i b i t s i n t e r b r e e d i n g between the two s p e c i e s . 3 3 -From my work and the experiments o f o t h e r s , i t appears t h a t leucopus w i l l not mate w i t h manlculatus i n c a p t i v i t y . The b l o c k to i n t e r b r e e d i n g may be m o r p h o l o g i c a l , b e h a v i o r a l , or p h y s i o l o g i c a l , and perhaps l i n k e d w i t h s i g h t o r s m e l l . The s m e l l of a strange male may be an e x t e r o c e p t i v e b l o c k to pregnancy i n white mice (Bruce and P a r r o t t , I 9 6 0 ) . These . workers found t h a t s i n g l e or s u c c e s s i v e pregnancies i n the same female could be b l o c k e d by the i n t r o d u c t i o n o f a strange male, p a r t i c u l a r l y a male o f a d i f f e r e n t s t r a i n from the stud male, near or w i t h the female. These i n h i b i t o r y e f f e c t s were a b o l i s h e d i n mice from which the o l f a c t o r y b u l b s had been removed. Perhaps the females o f e i t h e r leucopus or manlculatus, when mated w i t h animals of the other s p e c i e s , r e a c t i n much the same way. The odor of the strange male c o u l d be a more or l e s s permanent i n h i b i t o r t o pregnancy. Hence, s p e c i e s odor might p l a y a r o l e i n r e p r o d u c t i v e i s o l a t i o n and s p e c l a t i o n i n mammals i n g e n e r a l and leucopus and maniculatus i n p a r t i c u l a r . I w i l l p r e s e n t my own r e s u l t s On the r o l e o f odor i n i n t e r s p e c i e s r e a c t i o n i n a l a t e r s e c t i o n o f t h i s r e p o r t . 34. THE DISTRIBUTION OF PEROMYSCUS LEUCOPUS NOVEBORACENSIS AND PEROMYSCUS MANICULATUS GRACILIS D i f f e r e n c e s between P. 1. noveboracensis and P. m. g r a c i l i s were i n v e s t i g a t e d not only t o f i n d a method o f s e p a r a t i n g them but a l s o t o see i f d i f f e r e n c e s found c o u l d be used to e x p l a i n t h e i r d i s t r i b u t i o n . Attempts w i l l be made to r e l a t e the d i s t r i b u t i o n o f the mice w i t h environmental f a c t o r s , morphology, c o l o r o f pelage, b e h a v i o r , and s p e c i e s i n t e r a c t i o n . H i s t o r y of D i s t r i b u t i o n o f Peromyscus Knowledge o f the h i s t o r y of d i s t r i b u t i o n of s p e c i e s of the genus Peromyscus i n e a s t e r n North America might p r o v i d e an explan-a t i o n f o r t h e i r p r e s e n t range. Waters (I960) reviews the p o s t -Wisconsin r e d i s t r i b u t i o n o f mice of t h i s genus and s p e c u l a t e s on the sequence of events l e a d i n g t o s p e c i a t i o n and subsequent development of e x c l u s i v e ranges. He p r e s e n t s evidence t h a t the genus Peromyscus reached the e a s t e r n U n i t e d S t a t e s d u r i n g the e a r l y P l e i s t o c e n e . I t i s probable t h a t the f r e q u e n t s h i f t s and a l t e r n a t i o n o f c l i m a t e and v e g e t a t i o n d u r i n g the g l a c i a l and i n t e r g l a c i a l p e r i o d s o f the P l e i s t o c e n e a l s o caused Peromyscus to s h i f t f r e q u e n t l y , r e s u l t i n g i n h i g h l y v a r i a b l e s p e c i e s o f mice i n e a s t e r n North America. Waters proposes t h a t toward the end of the P l e i s t o c e n e , an i n c i p i e n t p o p u l a t i o n o f P. manlculatus occupied the h i g h e r e l e v a t i o n s of the southern h a l f o f the Appalachians, while an i n c i p i e n t P. leucopus p o p u l a t i o n occupied the lower e l e v a t i o n s to the e a s t , south, and west o f t h i s a r ea. H i s data i n d i c a t e 3 5 . that a genetic divergence took place i n the i n c i p i e n t P. leucopus population during the l a t e Pleistocene and resulted i n forms with either strongly or weakly bicolored t a i l s . Waters correlates the northward movement of maniculatus and leucopus with botanical data derived from Braun ( 1 9 5 0 ) . According to t h i s author, spruce was the f i r s t f o r e s t component to move northward, following the retreat of the Wisconsin ice cap. Oaks, at f i r s t associated with pines, moved i n a f t e r the spruce. Maniculatus moved north with the expanding spruce forest, before leucopus. Leucopus began to move northward with the expansion of oak forests, the population west of the Appalachians spreading throughout the midwest, that east of the Appalachians spreading along the A t l a n t i c coastal p l a i n . Thus, maniculatus-was associated with coniferous and leucopus with deciduous f o r e s t . The present r e l a t i o n s h i p . o f these species with the vegetation of Ontario w i l l be discussed l a t e r . In summary, Waters f e e l s that the species and subspecies of Peromyscus are probably l i m i t e d to t h e i r present day ranges by ch a r a c t e r i s t i c s developed through the la t e Pleistocene and during t h e i r post-Wisconsin movement northward. Present D i s t r i b u t i o n of Peromyscus i n Ontario The present d i s t r i b u t i o n of the two species has been outlined by several authors (Osgood, 1909J H a l l and Kelson, 1 9 5 9 ) . For this study, I obtained trapping records of Peromyscus i n Ontario from the Royal Ontario Museum of Zoology. These data are presented i n F i g . 18(a,b,c) and indicate where Peromyscus have been trapped up to 1960-61. Also included i n these figures are data I have Figure 18(a). Map of Counties and D i s t r i c t s of southeastern Ontario. 1. Essex 2. Kent 3. Lambton 4. E l g i n 5 . Middlesex 6. Norfolk 7. Oxford 8. Brant 9. Haldimand 10. Welland 11. L i n c o l n 12. Wentworth 13. Waterloo 14. Perth 1 5 . Halton 16. Huron 18. Peel 1 9 . York 2 0 . D u f f e r i n 2 1 . Ontario 2 2 . Durham 2 3 . Northumberland 24. Prince Edward 2 5 . Bruce 26. Grey 2 7 . Simcoe 28. V i c t o r i a 2 9 . Peterborough 35. Dundas 36. Stormont 37. Glengarry 38. Prescott 39. Russell 40. Carleton 41. Lenarck 42. Haliburton 43. Muskoka 44. Parry Sound 45. Renfrew 46. Manitoulin 47. Nlpissing 3 0 . Hastings 3 1 . Lennox and Addington 48. Algoma 3 2 . Frontenac 49. Sudbury 3 3 . Leeds 5 0 . Timiskamlng 17- Wellington 34-. G r e n v i l l e (This legend also applies to Figures 18(b) and 18(c)) F i B . 18(a). COUNTIES AND DISTRICTS OF SOUTH-EASTERN ONTARIO F i g u r e 18(b). Range of P. 1. noveboracensis i n s o u t h e a s t e r n O n t a r i o , taken p r i m a r i l y from R.O.M.Z. t r a p p i n g r e c o r d s . The s t i p p l e d areas, i n d i c a t e r e c o r d ( s ) of animal(s) t e n t a t i v e l y -i d e n t i f i e d as P. 1. noveboracensis. The b l a c k areas i n d i c a t e c o u n t i e s or d i s t r i c t s where noveboracensls has been trapped. Figure 18(b). RANGE OF R L. NOVEBORACENSIS IN S O U T H - E A S T E R N O N T A R I O . (ROMZ. FILES) F i g u r e 1 8 ( c ) . Range of P. m. g r a c i l i s i n south-e a s t e r n O n t a r i o , taken p r i m a r i l y from R.O.M.Z. t r a p p i n g r e c o r d s . The s t i p p l e d areas i n d i c a t e r e c o r d ( s ) o f animal(s) t e n t a t i v e l y I d e n t i f i e d as P. m. g r a c i l i s . The b l a c k areas i n d i c a t e c o u n t i e s or d i s t r i c t s where g r a c i l i s has been trapped. Figure 18(c). RANGE OF R M. GRACILIS IN S O U T H - E A S T E R N O N T A R I O (R.OMZ. FILES) 3 6 . obtained from published faunal surveys f o r portions of Ontario (Wright and Simpson, 1 9 2 0 ; Snyder and Logler, 1 9 3 0 ; Davis, 1 9 3 1 ; Snyder and Logier, 1 9 3 1 ; Clarke, 1 9 3 3 ; Snyder et a l , 1 9 4 1 ; Jameson, 1 9 4 3 ; Rand, 1 9 4 5 ; Warburton, 1 9 4 9 ; Brown and Lanning, 1954; Rutter, 1 9 5 9 ) . The d i s t r i b u t i o n s of P. 1 . noveboracensis and P. m. g r a c i l i s shown i n f i g . I8(b,c) are only rough approximations because: (1) Trapping records for the whole of southeastern Ontario are Incomplete, ( 2 ) Many specimens are only t e n t a t i v e l y i d e n t i f i e d , and ( 3 ) Trapping records were mapped by counties and d i s t r i c t s , not by s i t e of capture. Osgood's ( 1 9 0 9 , p. 114, frontispiece) d i s t r i b u t i o n maps of P. 1 . noveboracensis and P. m. g r a c i l i s i n Ontario showed that g r a c i l i s occupied the area east of the Great Lakes up to the border of Quebec, while noveboracensis was r e s t r i c t e d to southern Ontario. Recent data (Rutter, 1951 ; R.O.M.Z. trapping records), show that the ranges of the two. species have changed s l i g h t l y ; g r a c i l i s has moved i t s southern boundary northward, while noveboracensls has extended I t s northern boundary further north. Correlation of Ranges of Mice with Vegetation The d i s t r i b u t i o n s of the mice can be roughly correlated with types of vegetation. Osgood ( 1 9 0 9 ) , and Cross and Dymond (1929) noted that g r a c i l i s preferred the colder, more moist places, or deep, mostly coniferous woods, while leucopus preferred the warmer, dryer, more open country, or deciduous woods. The changes i n d i s t r i b u t i o n s of the mice, since 1 9 0 9 , can also be roughly correlated with changes i n types of vegetation. 37. S i n c e 1 9 0 9 , c o n s i d e r a b l e settlement has taken p l a c e i n southern O n t a r i o and much of the n a t i v e v e g e t a t i o n has been removed. Settlement has spread northward and c o n i f e r f o r e s t has been c l e a r e d . These c l e a r i n g s encouraged the growth of deciduous t r e e s of the conifer-hardwood subclimax. G r a c i l i s has withdrawn i t s range northward, presumably f o l l o w i n g the r e c e d i n g border of c o n i f e r o u s f o r e s t where i t p r e f e r s to l i v e . Leucopus has extended i t s range northward, presumably f o l l o w i n g the expansion of hardwood f o r e s t . The a s s o c i a t i o n of maniculatus w i t h c o n i f e r o u s f o r e s t and leucopus w i t h deciduous f o r e s t was r e c e n t l y r e p o r t e d by K l e i n ( 1 9 5 9 ) . He found maniculatus to be p o s i t i v e l y a s s o c i a t e d w i t h p l a n t s of the hemlock-white p i n e - n o r t h e r n hardwoods f o r e s t r e g i o n and avoided p l a n t s o f the oak-chestnut f o r e s t r e g i o n . Leucopus was p o s i t i v e l y a s s o c i a t e d w i t h p l a n t s o f the oak-chestnut f o r e s t r e g i o n and avoided p l a n t s of the hemlock-white pine - n o r t h e r n hardwoods f o r e s t r e g i o n . F u r t h e r evidence f o r the a s s o c i a t i o n o f leucopus and maniculatus w i t h f o r e s t r e g i o n s can be shown by comparing t h e i r ranges w i t h the f o r e s t r e g i o n s o f s o u t h e a s t e r n O n t a r i o . The f o r e s t r e g i o n s o f O n t a r i o are w e l l known and have r e c e n t l y been r e d e s c r i b e d by Rowe ( 1 9 5 9 ) . Comparing the ranges o f leucopus and maniculatus a map of f o r e s t r e g i o n s of s o u t h e a s t e r n O n t a r i o ( f i g . 19) shows s e v e r a l c o r r e l a t i o n s . The range of maniculatus l i e s p r i m a r i l y i n the c o n i f e r o u s f o r e s t r e g i o n while t h a t o f leucopus l i e s i n the deciduous f o r e s t r e g i o n . The area where t h e i r ranges o v e r l a p c o i n c i d e s w i t h the c o n i f e r o u s - d e c i d u o u s f o r e s t t r a n s i t i o n zone. F u r t h e r , c o r r e l a t i o n w i t h the p r i n c i p l e F i g u r e 19. F o r e s t r e g i o n s of s o u t h e a s t e r n O n t a r i o ( a f t e r Rowe, 1 9 5 9 ) • 1 . Deciduous f o r e s t r e g i o n N i a g a r a s e c t i o n 2 - 1 0 , 1 2 . Great Lakes-St. Lawrence f o r e s t r e g i o n 2 . Huron-Ontario s e c t i o n 3. Georgian Bay s e c t i o n 4. A l g o n q u l n - P o n t l a c s e c t i o n 5 . Middle Ottawa s e c t i o n 6. Upper S t . Lawrence s e c t i o n ' 7 . A l g o n q u i n - F o n t i a c s e c t i o n 8 . Sudbury-North Bay s e c t i o n 9- Timagami s e c t i o n 1 0 . Algoma s e c t i o n 1 2 . H a i l e y b u r y c l a y s e c t i o n 1 1 . B o r e a l f o r e s t r e g i o n M i s s i n a i b i - G a b o n g a s e c t i o n F i g u r e i 9 . FOREST REGIONS OF S O U T H - E A S T E R N O N T A R I O ( A F T E R R O W E , 1959) 38. t r e e s i n each r e g i o n shows t h a t the range of maniculatus i s a s s o c i a t e d w i t h t r e e s such as spruce, pine, aspen, and b i r c h , w h i l e t h a t of leucopus i s a s s o c i a t e d w i t h sugar maple and beech. From the evidence presented here, I conclude t h a t manic-u l a t u s i s a s s o c i a t e d w i t h r e g i o n s of c o n i f e r o u s f o r e s t growth and leucopus w i t h r e g i o n s o f deciduous f o r e s t growth. Examination of f i g . 18(b) r e v e a l s a somewhat d i s c o n t i n u o u s d i s t r i b u t i o n f o r g r a c i l i s a long the s o u t h e a s t e r n edge of Lake Huron, a t the south end o f Lake E r i e , and along the n o r t h e r n edge of Lake O n t a r i o . Perhaps g r a c i l i s i s p r e s e n t i n these areas i n r e l i c stands o f c o n i f e r o u s f o r e s t . R e l a t i o n s h i p o f Ranges o f Mice to Food. Temperature and Water C o r r e l a t i o n s between v e g e t a t i o n and d i s t r i b u t i o n may o n l y be s u p e r f i c i a l and not c a u s a l f a c t o r s . Other f a c t o r s such as food, temperature, and water may be the ones governing the d i s t r i b u t i o n s o f these mice. The foods eaten by leucopus and maniculatus were mentioned by Dice ( 1 9 2 2 ) , C o g s h a l l ( 1 9 2 8 ) , B u r t ( 1 9 4 0 ) , Hamilton (1941), Jackson ( 1 9 5 2 ) , Cameron ( 1 9 5 6 ) , W i l l i a m s ( 1 9 5 9 ) , Connor ( I 9 6 0 ) , Getz ( 1 9 6 1 ) , and Howard ( 1 9 6 1 ) . Both s p e c i e s ate a v a r i e t y o f foods i n c l u d i n g seeds, nuts, I n s e c t s , a r a c h n i d s , f r u i t , f u n g i , green v e g e t a t i o n , r o o t s , and m o l l u s c s . No apparent d i f f e r e n c e s i n food p r e f e r e n c e were e x h i b i t e d . Food i s not c l e a r l y r e l a t e d to the d i s t r i b u t i o n of these mice. Temperature t o l e r a n c e s o f leucopus and maniculatus might be f a c t o r s i n f l u e n c i n g t h e i r d i s t r i b u t i o n . However, Howard (1951), and E s k r l d g e and U d a l l (1955), found t h a t both s p e c i e s c o u l d 39. withstand freezing temperatures provided s u f f i c i e n t food was available. Sealander (1952) showed that P. leucopus could ' endure temperatures from +35 to -25°C. Getz (1961) concluded that temperatures had no obvious influence upon the l o c a l d i s t r i b u t i o n of P. leucopus. High temperatures probably do not aff e c t the mice because of t h e i r nocturnal behavior. Perhaps the a v a i l a b i l i t y of food during the winter d i f f e r s f o r each species and t h i s governs t h e i r respective d i s t r i b u t i o n s . No data are available on t h e i r a b i l i t y to survive t h i s c r i t i c a l period under conditions of winter temperature, provided with selected kinds and amounts of food. From the evidence above, I conclude that there i s l i t t l e difference i n temperature tolerance between leucopus and manlculatus. Thus temperature, by i t s e l f , does not appear to be a factor determining t h e i r d i s t r i b u t i o n s . The water requirements of the two species might influence t h e i r d i s t r i b u t i o n . Lindeborg (1952) observed that leucopus and manlculatus displayed s i m i l a r reactions to l i m i t e d amounts of water. Neither could survive on 0.2 cc./day and both l o s t weight on 0.4 cc./day. K l e i n (1959) showed that both species used about the same amount of water: leucopus, 0.43 cc./gram body weight or 7.6 cc./individual/day; g r a c i l i s , 0.42 cc./gram body weight or 7.4 cc./individual/day. These studies Indicate that water requirements for leucopus and maniculatus are not appreciably d i f f e r e n t . This factor does not appear responsible for t h e i r d i s t r i b u t i o n s . 40. The Morphology and Pelage C o l o r o f the Mice as an E x p l a n a t i o n of D i s t r i b u t i o n D i f f e r e n c e s i n morphology and c o l o r o f pelage between the two s p e c i e s might be c o r r e l a t e d w i t h d i f f e r e n c e s i n d i s t r i b u -t i o n s . Dice (1940) suggested t h a t c o r r e l a t i o n o f t a i l l e n g t h and h i n d f o o t l e n g t h w i t h type of environment might e s s e n t i a l l y be a c o r r e l a t i o n with b e h a v i o r . L o n g e r - t a i l e d mice, f o r example, are u s u a l l y found i n h e a v i l y f o r e s t e d areas (Pox, 1948), and t h i s i n t u r n might be c o r r e l a t e d w i t h s e m i - a r b o r e a l b e h a v i o r . Horner (1954) demonstrated that s e m i - a r b o r e a l Peromyscus were s i g n i f i c a n t l y b e t t e r than t e r r e s t r i a l Peromyscus i n t h e i r a b i l i t y to climb a r t i f i c i a l t r e e trunks and c r o s s gaps of v a r y i n g widths. She a l s o showed t h a t the long t a i l was an adaptive s t r u c t u r e which f a c i l i t a t e d s e m i - a r b o r e a l e x i s t e n c e . Although P. manlculatus has a lo n g e r t a i l than P. leucopus, b o t h are known to be s e m i - a r b o r e a l (Chenoweth, 1917; B u r t , 1 9 4 0 ; B l a i r , 1 9 5 0 ; Linduska, 1 9 5 0 ; Horner, 1954; Connor, I 9 6 0 ) . Horner ( 1954) c l a s s i f i e d b o t h P. 1 . noveboracensis and P. m. g r a c i l i s as b e i n g s e m i - a r b o r e a l and d e t e c t e d l i t t l e d i f f e r e n c e between them i n c l i m b i n g performances. I observed b o t h s p e c i e s c l i m b i n g g l a s s d r i n k i n g tubes and cage w a l l s w i t h equal f a c i l i t y . S i n c e no d i f f e r e n c e i n the c l i m b i n g a b i l i t i e s of maniculatus over leucopus have been found, I conclude t h a t the s l i g h t l y l o n g e r t a i l o f maniculatus i s not c a u s a l l y r e l a t e d to i t s d i s t r i b u t i o n . C o r r e l a t i o n between s i z e of ot h e r body p a r t s and the d i s t r i b u t i o n o f e i t h e r s p e c i e s can only be suggested. For example, the s l i g h t l y l o n g e r r o s t r a l l e n g t h o f leucopus might 41. p r o v i d e more l e v e r a g e f o r e a t i n g l a r g e , hard foods such as nuts t h a t are commonly found i n i t s range. However, t h i s i s only c o n j e c t u r e and I have found no s u p p o r t i n g d a t a on Peromyscus i n the l i t e r a t u r e . S i m i l a r m o r p h o l o g i c a l d i f f e r e n c e s f o r food h a n d l i n g have been observed f o r b i r d s (Robbins, 1932; Lack, 1944, 1947). Lack (1947) c o n s i d e r s t h a t the marked d i f f e r e n c e i n s i z e of beaks of the Galapagos f i n c h e s i s an a d a p t a t i o n f o r t a k i n g foods of d i f f e r e n t s i z e . The pelage c o l o r of mammals tends to be p o s i t i v e l y c o r r e l a t e d w i t h the c o l o r of the s o i l s u r f a c e . Dice (1940) demonstrated t h i s c o r r e l a t i o n between s o i l c o l o r and c o l o r of pelage of Peromyscus and gave f u r t h e r evidence (1947) of i t s p r o t e c t i v e f u n c t i o n . The c o l o r s of pelage of noveboracensis and g r a c i l i s are n e a r l y i d e n t i c a l , although the former tends to be more b r i g h t l y c o l o r e d . B r i g h t e r pelage may have a p r o t e c t i v e f u n c t i o n In the autumn when l e a v e s i n deciduous f o r e s t s become h i g h l y c o l o r e d . G r a c i l i s , with i t s l e s s b r i g h t l y c o l o r e d pelage might g a i n more p r o t e c t i o n i n the l e s s b r i g h t l y c o l o r e d c o n i f e r o u s f o r e s t s . D i f f e r e n c e s i n pelage c o l o r between the two s p e c i e s , however, are so s l i g h t t h a t I f i n d i t h a r d to be convinced t h a t t h i s i s of importance i n the d i s t r i b u t i o n of these forms. Behavior of the Mice as a Cause o f D i s t r i b u t i o n D i f f e r e n c e s i n b e h a v i o r between leucopus and maniculatus might be f a c t o r s i n f l u e n c i n g t h e i r d i s t r i b u t i o n . F o r t h i s reason, they were observed at every o p p o r t u n i t y i n the l a b o r a t o r y . Both s p e c i e s were good climbers and r e a d i l y climbed the g l a s s 42. drinking tubes on gravity water bottl e s i n t h e i r cages. When I cleaned out cages, occasionally an animal would escape. Escapees of each species tended to behave d i f f e r e n t l y . Maniculatus moved comparatively slowly and appeared to be uncertain about which d i r e c t i o n to go. Leucopus ran quickly as soon as i t had escaped from the cage. Horner (1954) also noted that leucopus moved more quickly and unhesitatingly than maniculatus. This difference i n approach to a new s i t u a t i o n could be re l a t e d to the speed at which the animal i s capable of t r a v e l l i n g , or to some inherited factor related to i t s normal habitat. Leucopus has been found to be the faster of the two on the ground (Layne and Benton, 1954). These investigators found that leucopus could t r a v e l at 8.46 feet/second (range, 6.9-10.0 feet/second), while maniculatus could t r a v e l only 6.4 feet/second (range, 6.2-6.6 feet/second). The two species of Peromyscus reacted d i f f e r e n t l y to handling. P. 1. noveboracensis was d i f f i c u l t to catch and would run and jump r a p i d l y around the cage. P. m. g r a c i l i s was f a i r l y e a s i l y approached and often came out to investigate the opening of the cage door. Sv l h l a (1932) found leucopus to be more excitable and d i f f i c u l t to handle than P. m. b a l r d i i . Horner (1954) and Foster (1959) reported that g r a c i l i s was more e a s i l y handled than b a l r d i i . I found differences i n the behavior of leucopus and maniculatus. Leucopus was the more highly excitable and fa s t e r moving of the two forms. Leucopus as mentioned above, i s considered by many workers to be the more enterprising, less h a b i t a t - r e s t r i c t e d mouse 43. (Wilson, 1945; Brand, 1955; Connor, I960; W i r t z and Pearson, I960). Perhaps the e n t e r p r i s e and g r e a t e r speed of leucopus r e f l e c t s i t s wide choice o f h a b i t a t s . M a n l c u l a t u s i s l e s s e n t e r p r i s i n g and slower o f movement than leucopus and t h i s may-be r e l a t e d to i t s presence i n more homogeneous h a b i t a t s . Whether t h i s b e h a v i o r o f each form i s cause or e f f e c t of the v e g e t a t i o n i n which they occur, i s unknown. I n t e r a c t i o n Between S p e c i e s as a Cause o f D i s t r i b u t i o n The r o l e of s p e c i e s i n t e r a c t i o n i n d i s t r i b u t i o n has been examined by D i c e (1922), K l e i n (1959), and Sheppe ( I 9 6 I ) . K l e i n (1959) r e p o r t e d t h a t although there was some e c o l o g i c a l s e p a r a t i o n of leucopus and manlculatus, no evidence was p r e s e n t to suggest t h a t b e h a v i o r a l f a c t o r s , such as i n t e r s p e c i f i c antagonism, p l a y e d a p a r t i n d e t e r m i n i n g the l o c a l d i s t r i b u t i o n o f the forms. I n t e r a c t i o n may not o n l y prevent sympatric s p e c i e s from i n t e r b r e e d i n g , but i t might a l s o r e s t r i c t t h e i r d i s t r i b u t i o n i n l o c a l a reas. Sheppe (1961) found that P. oreas and P. maniculatus have more r e s t r i c t e d h a b i t a t p r e f e r e n c e s i n the a r e a of sympatry than where each occurs alone. The r e s t r i c t i o n o f h a b i t a t d i s t r i b u t i o n was a t t r i b u t e d , i n p a r t , to i n t e r s p e c i f i c c o m p e t i t i o 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 may or may not i n f l u e n c e d i s t r i b u t i o n . K l e i n (1959) found no antagonism or c a n n i b a l i s m r e s u l t e d from keeping leucopus and manlculatus together. He observed t h a t t h e i r i n i t i a l response to each other was one of c a u t i o n , but soon they c o u l d be found h u d d l i n g together. In my c r o s s b r e e d i n g experiments, mixed p a i r s o f both s p e c i e s l i v e d amicably and no antagonism 4 4 . between the two was evident. Unfortunately, i n s u f f i c i e n t numbers of l i v e animals were available to test antagonism between two pairs (one pair of each species) during the breeding season. Perhaps at that time of the year, antagonism plays a large r o l e i n keeping the species apart. An experiment with one p a i r of leucopus kept i n the same cage as two successive pairs of l o c a l maniculatus, gave i n t e r e s t i n g observations. In both instances, the female of the pair of maniculatus was found dead. The dead animals were not eaten but were mutilated, and the blood-spattered cage gave evidence that the dead animals had moved about before they had succombed. These deaths occurred several months afte r both pairs had been placed i n the cage and, at no time was antagonism shown between the animals. The dead animals had been b i t t e n about the ears and the t a i l s were badly chewed. Neither the pair of leucopus nor the male maniculatus showed evidence of having fought. No explanation for t h i s behavior has been found. Burt ( 1 9 4 0 ) reported that the female leucopus holds a d e f i n i t e t e r r i t o r y i n the breeding season and i s antagonistic to other leucopus females. However, both maniculatus females were k i l l e d i n mid-winter. I n t r a s p e c i f i c antagonism was evident i n cages containing only leucopus. In one cage, four males were discovered s t a r t i n g to eat the warm carcass of t h e i r female l i t t e r mate. The dead animal had a badly chewed t a i l and neck. In another cage, three of seven male leucopus were found huddled i n the corner of the cage farthest from the nest. A l l had raw, stubby, swollen t a i l s , and would not enter.the nest even when prodded. The other four leucopus were not injured. Reasons f o r antagonism i n leucopus 4 5 . are unknown. Only one instance of antagonism was noted among manlculatus. A female P. m. austerus k i l l e d and p a r t l y ate her three l i t t e r mates. Further i n v e s t i g a t i o n revealed that lack of food had prompted the cannibalism. Interaction Between Species by Odor Interaction between the two forms could be responsible f o r t h e i r differences i n d i s t r i b u t i o n and a b i l i t y to l i v e sympatrically, s t i l l r e t a i n i n g separate i d e n t i t y . Moore (1961) reported that there was evidence to support the role of o l f a c t i o n i n the sexual i s o l a t i o n of P. maniculatus and P. polionotus. Because novebora-censis and g r a c i l i s occur sympatrically, and are not known to interbreed where they do, i t seemed plausible that odor discrimin-a t i o n might be involved i n t h e i r apparent sexual I s o l a t i o n . To t e s t t h i s , plans were drawn up f o r an odor discrimination apparatus (olfactometer). Apparatus for Testing Recognition of Odor Certain s p e c i f i c a t i o n s had to be considered i n the design of the olfactometer. F i r s t l y , i t should be as light-proof and a i r - t i g h t as possible to prevent external s t i m u l i from a f f e c t i n g r e s u l t s . Secondly, i t should present the animal with a number of choices, each of which could equally be taken. Thirdly, some method of recording the animal's movement within the apparatus must be Incorporated i n the design of the apparatus. Fourthly, the suspected odor must be r e a d i l y obtainable and i n a form that could be used i n the apparatus. After consideration of these s p e c i f i c a t i o n s , a t e s t i n g 46. chamber was constructed ( F i g . 20). The apparatus consisted of a central chamber with moveable doors connecting to three r a d i a t i n g arms. I t was constructed e n t i r e l y of sheet metal and was made as a i r - t i g h t and light-impervious as possible. The three radiating, arms were spaced equidistantly to give the animals an equal opportunity to enter any one of them. Three arms were chosen because there were two species odors to test and the t h i r d could be used as a control. The problem of recording the a c t i v i t y of an animal i n a metal container was solved by having a moveable j o i n t i n the middle of each arm. A projecting piece of metal (writer) was soldered onto the end of each arm. The writer traced a record of the movement of the animal i n the end of the arm, on a piece of smoked kymograph paper. Selection of a source of odor was a problem because Peromyscus have a number of glands (eg. anal, preputial, c l i t o r a l ) which could be responsible for a species-specific ofor and, almost nothing i s known about t h e i r function. Mammals are known to use odor for sexual a t t r a c t i o n , t e r r i t o r y and home range marking, and possibly f o r protection (Bourliere, 1956, pp. 103-107, 225-230). Hedlger (1949, from Bourlidre, 1956) reported the use of urine and faeces by the male pygmy hippopotamus i n marking i t s t e r r i t o r y . The ease of obtaining urine and faeces, and the knowledge that i t i s used by mammals i n the marking of t e r r i t o r i e s and t r a i l s , made t h i s the choice f o r a source of odor. The apparatus was set up as i n F i g . 20(B). So i l e d paper cage l i n i n g was placed i n two of the three arms. The t h i r d arm was used as the control and contained only clean paper cage l i n i n g . F i g u r e 20. Diagram of odor d i s c r i m i n a t i o n apparatus ( o l f a c t o m e t e r ) . A. P l a n o f apparatus as seen from above. B. S i d e view of apparatus i n o p e r a t i o n . 16' O D O R D O O R L E V E R C E N T R A L C H A M B E R WRITING TIP M O V E A B L E J O I N T A . P L A N B . E L E V A T I O N E L A S T I C B A N D RING S T A N D K Y M O G R A P H D R U M D I S C R I M I N A T I O N A P P A R A T U S 47., A mouse ( t e s t e r ) was then p l a c e d i n the c e n t r a l chamber f o r 1 0 - 1 5 minutes to a l l o w i t to become accustomed to the apparatus. Each experiment was run at the same time of day ( 5 : 3 0 P.M.) and f o r the same l e n g t h of time (one h o u r ) . No animal was used f o r more than a s i n g l e experiment. To s t a r t an experiment, three kymographs "attached" t o the ends of the arms were turned on and doors l e a d i n g from the c e n t r a l chamber to the arms were Opened. Entrance of the mouse i n t o the ends of the arms was recorded as a " d i p " on the kymograph paper. The i n i t i a l movement of the mouse was u s u a l l y r e c o r d e d as a s e r i e s o f r a p i d v i s i t s to each arm. G r a d u a l l y the mouse would s e t t l e down and te n d t o remain l o n g e r i n one of the arms. R e s u l t s o f T e s t s w i t h the Ol f a c t o m e t e r These p r e l i m i n a r y experiments were run to t e s t the d e s i g n of the apparatus and to see i f mice do respond to t h e i r own or oth e r s p e c i e s odors. Seven experiments were done and the r e s u l t s are g i v e n i n the Appendix (Table V ) . A summary of the r e s u l t s i s g i v 6 n i n Table 3 . Table 3 . R e s u l t s of odor d i s c r i m i n a t i o n experiments. Expt. No. T e s t e r Odor No. o f Times - E n t e r e d Arm % of T o t a l Time i n Arms 1. 9P.l.n. C o n t r o l cfand ?P.m.£. <*and ? P . l . n . 4 6 10 * 5.2 11.7 83.1 * 2. P.m.£. R e s i d u a l c o n t r o l R e s i d u a l cfand 9P.m.£. R e s i d u a l d a n d?J?.l.n. 7 * 6 6 18.5 44 . 0 * 37.5 48. Table 3 (cont'd). Results of odor discrimination experiments. Expt. No. Tester Odor No. of Times Entered Arm % of Total Time i n Arms 3. cfP.m.£. Control cfand $P.m.£. cfand 9P.l.n. 28 33 * 23 44 .0 * 25.0 31.0 4. 9P.S«£* Control cfand 9P.m.£. Cfand 9P.l.n. 31 * 25 30 62.6 * 15.9 21.5 5. ? P . l . n . Control 9P.m.£. cfP.m.g. 30 * 22 25 85.3 * 4.6 10.1 6. Cfp.l.n. Control cfand 9 P.m.g_. cfand 9 P.l.n. 11 18 31 * 5.4 20.8 73.8 * 7. £P.m.fi. Control cfP.rn.g_. Oand 9 P.l.n. 20 31 * 22 4.0 79 ~. 3 * 16.7 * denotes the greatest number of times any arm was entered and the greatest % of t o t a l time spent i n any arm. Although t h i s odor discrimination experiment was intended to be only a preliminary study and few tests were run, I believe the above r e s u l t s are worthy of comment. Since the tester was used only once, no bias was incurred by having the animal follow a learned path. The tests were run early i n January and none of the mice used were i n breeding condition. This r u l e s out possible changes i n response to odor caused by animals being i n estrus. The r e s i d u a l odor t e s t (no. 2) was conducted to f i n d out how e f f e c t i v e l y the apparatus had been cleaned. In t h i s test, only clean paper cage l i n i n g was placed at the end of each arm. It was decided that although r e s u l t s showed some re s i d u a l odor 49-was present i n the arms, i t would not greatly a l t e r the following r e s u l t s provided each arm was consistently used f o r the same odor. Generally, the tester entered most often and/or stayed longest i n the arm containing i t s own species odor (experiments no. 1, 2, 3, 6, 7). Exceptions to t h i s are experiments 4- and 5 where the animals entered more often and stayed longer i n the control. No explanation i s offered for experiment 4, hut i n experiment 5» the animal appeared to be avoiding the arms which both contained the odor of the other species. Perhaps there i s an active avoidance of the other species i n nature by odor? Another generalization that can be made i s that the testers appeared to prefer arms containing an odor to the arm used as a control (experiments no. 1, 2, 6, 7). Why t h i s i s so i s not known. The p o s s i b i l i t i e s of t e s t i n g species i n t e r a c t i o n by odor discrimination are only beginning to be r e a l i z e d . The r e s u l t s thus f a r indicate: (1) The apparatus works and (2) There seems to be measureable odor discrimination i n the mice. Continuation of these experiments promises to give valuable r e s u l t s which may hold the key to sexual i s o l a t i o n i n sympatrlc species and perhaps a clue to patterns of d i s t r i b u t i o n i n clo s e l y r e l a t e d species. 50. SUMMARY 1. The aims of t h i s study were: (1) to investigate morphological differences between two sim i l a r species of mice, Peromyscus leucopus noveboracensis and P. maniculatus g r a c i l i s , to f i n d a method of separating them, and (2) to determine whether morphological or other differences found between the two species could be used to explain t h e i r d i s t r i b u t i o n . 2. Most mice used i n thi s study came from areas i n Ontario where each was known to occur alone. Samples of leucopus came from areas near Kingston and manlculatus from Algonquin Park. The only exception i s the sample from the area of sympatry (Renfrew and Frontenac Counties).. 3. The measurements of 169 mice of both species were analyzed graphically and s t a t i s t i c a l l y to f i n d a method to separate them. The characters evaluated were: weight, hind foot length, ear length, body length, t a i l length, i n t e r p a r i e t a l width, i n t e r -p a r i e t a l length, s k u l l length, and r o s t r a l length. 4. No one character was useful i n separating the two forms. From an evaluation of the differences i n size of parts of the mice, indices were developed which completely separated leucopus and maniculatus of a l l sexes and ages examined. These indices were: ear length X t a i l length X i n t e r p a r i e t a l length or s k u l l length ear length X t a l l length X i n t e r p a r i e t a l length r o s t r a l length 5. The indices completely separated a sample of 12 leucopus and manlculatus trapped i n the zone of sympatry. 6. Breeding experiments were conducted to see i f the two species would interbreed. Four mixed pa i r s of leucopus and l o c a l 51. maniculatus were kept t o g e t h e r f o r over a year and d i d not produce o f f s p r i n g . Two-, c o n t r o l p a i r s of leucopus produced a t o t a l of t h r e e l i t t e r s and t h r e e c o n t r o l p a i r s of manlculatus produced a t o t a l o f two l i t t e r s (P. m. oreas f a i l e d t o b r e e d ) . No l i t t e r s r e s u l t e d from two mixed p a i r s of P. m. g r a c i l i s and P. 1. noveboracensis kept t o g e t h e r f o r 71 days. One p a i r of noveboracensis and one p a i r of g r a c i l i s ( c o n t r o l s ) , kept t o g e t h e r f o r the same l e n g t h of time, f a i l e d t o reproduce. 7. The d i s t r i b u t i o n o f P. 1. noveboracensis and P. m. g r a c i l i s i n O n t a r i o vras r e d e s c r i b e d u s i n g r e c e n t data. 8 . An attempt was made t o e x p l a i n the d i s t r i b u t i o n of each s p e c i e s on the b a s i s of f a c t o r s such as v e g e t a t i o n , food p r e f e r e n c e , temperature t o l e r a n c e , water requirement, morphology, c o l o r of pelage, and b e h a v i o r . Manlculatus was found to occur i n c o n i f e r o u s and leucopus i n deciduous v e g e t a t i o n . No c o r r e -l a t i o n was found between the ranges o f the mice and f o o d p r e f e -rence, temperature t o l e r a n c e , water requirement, morphology, and c o l o r of pelage. C o r r e l a t i o n between t h e i r ranges and b e h a v i o r was d o u b t f u l . 9. I n t e r a c t i o n between the s p e c i e s was i n v e s t i g a t e d as a cause of d i s t r i b u t i o n . Experiments were conducted i n an o l f a c t o m e t e r w i t h the odor o f mice. The purpose was to i n v e s t i g a t e i n t e r -a c t i o n between mice by o l f a c t i o n . P r e l i m i n a r y work suggested t h a t the mice responded t o the odor of other mice. A mouse en t e r e d more o f t e n and stayed l o n g e r i n a chamber c o n t a i n i n g the odor of i t s own s p e c i e s . A chamber c o n t a i n i n g odor was p r e f e r r e d to the c o n t r o l chamber without odor. 52. APPENDIX Table I. Measurement data plotted i n bar diagrams ( i n mms.). Ear L. Body L. T a i l L. Skull . L. Rostral L. Adult d"P.l.n. N=35 Range Mean 1 S.D. 2 S.E. 15.0-17.3 16.2 0.67 0.22 73.4-96.4 85.5 5-30 1.80 62.1-88.2 74.9 5.70 1.94 25.1-26.4 0.68 0.24 28.0 7.9-9.5 8.7 O.38 0.13 Adult 9P.l.n. N = 33 Range Mean 1 S.D. 2 S.E. 14.8-17-5 16.0 0.69 0.32 76.5-96.0 86.4 5.50 1.92 61.2-86.9 74.0 6.40 2.20 25.0-26.4 0.69 0.24 27. 9 7.9-9.1 8.6 O.32 0.11.. Adult d*P.m.g. N = 22 Range Mean 1 S.D. 2 S.E. 17.0-20.9 18.8 0.85 0.38 80.6-97.4 88.6 4.60 2.10 76.2-97.2 86.8 5.80 2.60 24.6-25.9 0.61 0.28 27. 0 7.6-9.1 8.5 0.40 0.18 Adult ?P_.m..g.. N=31 Range Mean 1 S.D. 2 S.E. 17.0-20.4 19.0 0.76 0.28 72.5-101.0 69.5-105.5 89.2 86.8 6.80 8.90 2.40 4.00 24.3-25.7 0.76 0.28 •27. 9 7.9-9.3 8.5 -0.39 0.14 Subad. c5p.rn.g_. N = 22 Range Mean 1 S.D. 2 S.E. 17.4-20.1 18.6 0.73 0.34 75.0-86.0 82.5 3.02 1.38 66.8-97.0 81.8 6.80 3.00 24.0-25.3 O.54 0.24 26. 1 7.7-8.6 8.2 0.21 0.10 Subad. ?P.m.g. N =26 Range Mean 1 S.D. 2 S.E. 17.5-20.1 18.7 0.82 0.32 79-4-89.2 83.2 2.99 1.18 75.1-90.9 82.3 4.45 1.74 24.1-25.1 0.52 0.20 •26. 1 7.7-9.1 8.3 0.37 0.15 Table I. (Continued) Measurement data plotted i n bar diagrams ( i n mms.) Int. L.* Int. W. Weight (gms.) Hind Foot L. Adult Range 6 . 8 - 9 - 0 2.1-3.4 i 5 . l O - 3 i . 2 5 1 9.4 - 2 2 . 0 ^ P . l . n . Mean 7 . 5 2 . 9 2 0 . 7 2 0 . 5 1 S.D. 0 . 5 1 0 . 3 3 3 . 2 6 0 . 7 0 N =35 2 S.E. 0 . 1 7 0 . 1 1 1 . 10 0.24 Adult Range 6.8-8 .3 2 . 0 - 3 . 6 13.16-25.46 18.4 -22.0 ?P.l.n. Mean 7-5 2.8 1 9 . 3 2 0 . 3 1 S.D. 0.42 O .36 1.04 0.76 N = 33 2 S.E. 0 . 1 5 0 . 1 3 O .36 • 0 . 2 6 Adult Range 8 . I - 9 . 8 2 . 3 - 3 . 9 15-13-24.27 2 0 . 5 - 2 2 . 2 <?P.m.£. Mean 9 . 2 3 . 1 18.8 21 .3 1 S.D. 0 . 3 2 0 . 3 3 2 . 4 3 O .53 N = 22 2 S.E. 0 . 1 5 0 . 1 5 1 . 10 0.24 Adult Range 7 . 9 - 9 . 9 2 . 5 - 3 - 9 1 3 . 3 9 - 2 3 . 9 2 2 0 . 0 - 2 2.1 ?P.m.£. Mean 9 - 1 3 . 0 18.9 2 1 . 0 1 S.D. O .38 0.27 3.04 0 . 5 2 N= 3 1 2 S.E. 0.14 0 . 0 5 1.08 0 . 1 9 Subad. Range 8.1-9.7 2 . 5 - 3 . 9 12.13-19-79 20.0-22.2 cfP.m.^. Mean 8 . 9 3.1 16.1 21.0 1 S.D. 0.38 0.26 1.68 0.65 N = 22 2 S.E. 0.17 0.12 0.76 0 . 3 0 Subad. Range 8 . I - 9 . 8 2 . 5 - 3 . 3 13-18-18.81 2 0 . 0 - 2 1 . 8 ?P.m.£. Mean 9 -0 3 . 0 16 .2 2 1 . 0 1 S.D. 0 . 3 6 0 . 2 5 1.49 0.49 N= 2 6 2 S.E. 0.14 0 . 0 5 O .58 0 . 1 9 i n t e r p a r i e t a l length, i n t e r p a r i e t a l width. 5 4 . Table I I . " t " values calculated i n comparisons of body parts Animals Compared Ear L. Body L. T a i l L. Ad. cfP.l.n. N= 3 5 X Ad. cfp.m.g. N =22 14 .534 3.441 *# 14.399 Ad. d P . l . n . N = 3 5 X Ad.+Subad.S P.m.g. N= 4 4 2 3 - 9 2 5 0 . 5 8 2 Nonsig. 19 .458 Ad.9 P.l.n. N= 3 3 X Ad.9 P.m.g. N - 3 1 2 0 . 5 3 2 3.881 19 .328 Ad. 9P.l.n. N= 3 3 X Ad. + Subad.9 P.m.g. N= 5 7 9.492 0 . 2 2 1 Nonsig. 25.164 4HHfr Ad .cf+^P.l.n. N = 68 X Ad . c f + 9 P.m . g . N= 5 3 5 1 . 4 3 6 10.987 49 .352 Ad. cTp.l.n. N= 3 5 X Ad. 9 P . l . n . N= 3 3 1.664 Nonsig. 1.400 Nonsig. 1.611 Nonsig. Ad.cf P.m.g. N= 2 2 X Ad.$ P.m.g. N= 3 1 0 . 0 7 1 Nonsig. 0 . 5 9 5 Nonsig. 0 . 0 0 0 Nonsig. Subad.cfp.m.g.' N= - 2 2 " ~ X Subad.2 P.m.g. N= 26 0 . 4 1 5 Nonsig. 0 . 6 5 1 Nonsig. 0 . 4 7 1 Nonsig. Ad.f Subad.d" P.m.g. N = 4 4 X Ad.+ Subad. £ P.m.g. N = 57 1.778 Nonsig. 1.967 Nonsig. 1 . 4 2 5 Nonsig. * * p i 0 . 0 0 5 *** P^ 0 . 0 0 1 5 5 . Table I I . (Continued) " t " values calculated i n Comparisons of body parts. Animals Compared Sk u l l L. Rostral L. Int. L./ Ad.0P.l.n. N=35 X Ad .c fp.m .g . N = 22 1.840 Nonsig. 1.682 Nonsig. 19.051 Ad.0* P.l.n. N = 35 X Ad.-1- Subad.cf P.m.g. N=44 5.136 ##* 6.088 30.096 Ad.9 P.l.n. N=33 X Ad.9 P.m.g. N =31 3.269 0.461 Nonsig. 23-278 Ad.9 P.l.n. N = 33 X Ad. -4- Subad. 9 P.m.g. N=57 7 .410 *#•»«• 4^738 34.782 Ad.c?-t-?P.l.n. N=68 X Ad .d'+?P.m.£. N = 53 7.326 3 -722 19 .308 Ad.cTP.l.n. N=35 X Ad.9 P.l.n. N=33 0 .000 Nonsig. 0.787 Nonsig. 0.356 Nonsig. Ad'. cfP.m .g . N = 22 X Ad. 9P.m .g . N = 31 0 .684 Nonsig. 0.000 Nonsig. 0.484 Nonsig. Subad.3 P.m.g. N = 22 X Subad.9 P.m.g. N = 26 0.606 Nonsig. 0.940 Nonsig. O.517 Nonsig. Ad.4- Subad.& P.m.g. N=44 X Ad. 9 Subad.? P.m.g. N=57 1.898 Nonsig. 1.445 Nonsig. •0.085 Nonsig. / i n t e r p a r i e t a l length * * p i 0 . 0 0 5 *** P ^ 0.001 T a b l e I I I . Data p l o t t e d In bar diagrams of i n d i c e s . E.L. X T.L. X I.L. E.L. X T.L. X I.L. SK.L. R.L. A d u l t J P . l . n . N = 46 Range Mean 1 S.D. 2 S.E. 2 . 6 6 - 4 . 0 9 3 . 4 5 0 . 3 7 0 . 1 2 5 7 . 9 8 - 1 2 . 4 7 1 0 . 4 3 1 .52 0.446 A d u l t °P.l.n. N=46 Range Mean 1 S.D. 2 S.E. 2 . 5 7 - 4 . 0 1 3 . 3 7 0 . 3 4 . 0 . 119 7 . 3 9 - 1 2 . 5 0 1 0 . 4 7 1 .19 0 . 3 5 0 A d u l t c?P.m.g_. N = 2 2 Range Mean 1 S.D. 2 S.E. 4 . 8 3 - 7 . 0 0 5-77 0 . 5 5 0 . 2 5 0 1 5 . 2 5 - 2 1 . 2 0 17.60 1 .53 0 . 6 9 6 A d u l t ?P.m.g. N= 3 1 Range Mean 1 S.D. 2 S.E. 4.54-7.14 5.80 0.64 0.228 14 . 5 4 - 2 1 . 9 3 1 7 . 6 2 1 . 9 2 0 . 6 8 6 Subad. dP.m.g. N = 2 2 Range Mean 1 S.D. 2 S.E. 4.26 - 6 . 5 0 5 . 3 9 O . 5 8 0.264 1 2 . 8 3 - 2 0 . 7 5 16.70 1 . 8 7 O . 8 5 0 Subad. ijlP.m.g. N = 26 Range Mean 1 S.D. 2 S.E. 4.76-6.14 5 . 5 2 0 . 3 8 0.149 14.26-18.84 16 .73 1 .31 0 . 5 1 4 * E.L.= ear l e n g t h , T.L«= t a i l l e n g t h , I.L.= i n t e r p a r i e t a l l e n g t h , SK.L.= s k u l l l e n g t h . 57. T a b l e IV. Bre e d i n g data Length o f No. of No. i n Time P a i r e d P a i r s L i t t e r s L i t t e r 67 days P . l . n . c / X P.l.n. 3 2 4 5 73 days P . l . n . d * X P . l . n . 9 1 4 365+ days P.m.o.C^ X P . l . n . 9 365+ days P.m.a.cf x P . l . n . $ 3 6 5f days P.l.n.C^ X P.m.a.£ 365+ days P.l.n.<^* X P.m. s p p . ^ 365+ days P.m.o. cT x Jr.m.o. 3 -365 + days P.m.a. P.m.a.Tr: 1 5 365+ days P.m.sppJ^X P.m. spp.+ 1 3 71+- days P . l . n . ^ X P . l . n . ^ 71-1- days P . l . n . X P.m.g.^ 71+ days P.m.g.C^* X P.m.g.? 71+- days P.m.g. . n. 4 - -P . l . n . = P. leucopus noveboracensis P.m.o.= P. maniculatus oreas P.m.a.= P. maniculatus austerus P.m.g.= P. maniculatus g r a c i l i s P.m. spp.=P. maniculatus (Mandarte I s l a n d , B r i t i s h Columbia) 58. Table V. R e s u l t s of odor d i s c r i m i n a t i o n experiments. Expt. No. T e s t e r Odor No. times E n t e r e d Arm Minutes Spent i n Arm % of T o t a l Time i n Arms 1. 9 P . l . n . C o n t r o l c£and 9 P.m.g. oand 9 P . l . n . 4 6 10 * 1.2 2.7 19.1 * 5.2 11.7 83.1 * 2. cfp.rn.g_. R e s i d u a l c o n t r o l R e s i d u a l cfand 9 P.m.g. R e s i d u a l cfand 9 P . l . n . 6 6 0.7 1.6 * 1.3 18.5 44.0 * 37.5 3. cf P.m.g. C o n t r o l <£and 9 P.m.g. "a n d 9 P . l . n . 28 33 * 23 5.7 * 3-3 4.0 44.0 * 25.0 31.0 4. $P.m.g. C o n t r o l o*and 9 P.m.g. Oand ^ P . l . n . 31 * 25 30 31.5 * 8.0 10.8 62.6 * 15.9 21.5 5. ? P . l . n . C o n t r o l 9P.m.g. eTP.m.g. 30 * 22 25 42.3 * 2.3 5.0 85.3 * 4.6 10.1 6. cf P . l . n . C o n t r o l <£and 9 P.m.g. oand 9- P . l . n . 11 18 31 * 0.5 2.1 7.4 * 5.4 20.8 73.8 * 7. 9 P.m.g. C o n t r o l cf P.m.g. o*and 9 P . l . n . 20 31 * 22 1.8 36.2 * 7.6 4.0 79-3 * 16.7 * denotes the g r e a t e s t number of times any arm was entered, the g r e a t e s t number of minutes spent i n one of the three arms, and the g r e a t e s t % of t o t a l time spent i n any arm. 5 9 . LITERATURE CITED Beer, J . R., C. F. MacLeod, and L. D. Frenzel 1957 . Prenatal survival and loss i n some C r i c e t i d rodents. J . Mammal. 3 8 : 392-402. Bendell, J . F. 1959- Food as a control of a population of white-footed mice, Peromyscus leucopus noveboracensis (Fischer). Can. J . Zool. 3 7 : 1 7 3 - 2 0 9 . B l a i r , W. F. 1 9 4 1 . The small mammal population of a hardwood forest i n northern Michigan. Contrlb. Lab. Vert. Genetics Univ. Mich'. 17: 1 - 1 0 . 1 9 4 2 . Systematic rel a t i o n s h i p s of Peromyscus and several related genera as shown by the baculum. J . Mammal. 2 3 : 1 9 6 -204. 1950. E c o l o g i c a l factors i n speciation of Peromyscus. Evol. 4 : 2 5 3 - 2 7 5 . BourlieVe, F. 1 9 5 6 . The natural history of mammals. A. A. Knopf, Inc., N. Y. 364 pp. Brand, R. H. 1955* Abundance and a c t i v i t y of the wood mouse (Peromyscus leucopus noveboracensis) i n r e l a t i o n to the character of i t s habitat. PhD Thesis, Univ. Mich. 154 pp. Braun, E. L. 1 9 5 0 . Deciduous forests of eastern North America. The Blakiston Co., P h i l a . 596 pp. (In Waters, i 9 6 0 ) . Brown, N. R. and R. G. Lanning. 1 9 5 4 . The mammals of Renfrew County, Ontario. Can. F i e l d Nat. 6 8 : 171-180. Bruce, H. M. and D. M. V. Parrott. I960. Role of olfa c t o r y sense i n pregnancy block by strange males. S c i . 1 3 1 : 1526; Burt, W. H. 1 9 4 0 . T e r r i t o r i a l behavior of populations of some small mammals i n southern Michigan. Misc. Publ. Mus. Zool. Univ. Mich. 4 5 : 1 - 5 8 . 1 9 4 8 . The mammals of Michigan. Univ. Mich. Press, Ann Arbor. 288 pp. I960. Bacula of North American mammals. Misc. Publ. Mus. Zool. Univ. Mich. 113: 1-76. f and R. P. Grossenheider. 1 9 5 2 . A f i e l d guide to the mammals. Houghton M i f f l i n Co., Boston. 200 pp. Cameron, A. W. 1 9 5 6 . A guide to eastern Canadian mammals. Natl. Mus. Can. Dept. N. A f f a i r s Nat. Res. Natl. Parks Bd. 72 pp. 60. Cameron, A. W. 1 9 5 8 . Mammals of the islands i n the gulf of St. Lawrence. N a t l . Mus. Can. B i o l . Series 5 3 . B u l l . 154 . 165 PP-Chenoweth, H. E. 1917 . Reactions of certain moist forest animals to a i r conditions, and i t s bearing on problems of mammalian d i s t r i b u t i o n . B i o l . B u l l . 3 2 : 183-201. Chew, R. M. 1 9 5 1 . The water exchanges of some small mammals. Ecol. Monog. 2 1 : 2 1 5 - 2 2 5 -Clarke, C. H. D. 1 9 3 3 . Some f i e l d notes on the abundance of small mammals. Can. F i e l d Nat. XLVII: 7 3 - 7 4 . Cockrum, E. L. 1 9 5 4 . Non-geographic v a r i a t i o n i n c r a n i a l measure-ments of wild-taken Peromyscus leucopus noveboracensis. J . Mammal. 3 5 : 367-376. Cogshall, A. S. 1 9 2 8 . Food habits of deer mice of the genus Peromyscus i n c a p t i v i t y . J . Mammal. 9 : 217-221. C o l l i n s , H. H. 1 9 2 3 . Studies of the pelage phases and of the nature of color v a r i a t i o n i n Peromyscus. J . Exp. Zool. 3 8 : 45-108. Connor, P. F. I960. The small mammals of Otsego and Schoharie Counties, New York. N. Y. Mus. S c i . Svce. B u l l . 3 8 2 , Albany, N. Y. 84 pp. Cross, E. C. and J . R. Dymond. 1929. The mammals of Ontario. Roy. Ont. Mus. Zool. Hdbk. 1 . 56 pp. Davenport, C. B. 1935• V a r i a t i o n i n proportions among mammals, with reference to man. J . Mammal. 16: 2 9 1 - 2 9 6 . Davis, D. E. 1 9 5 6 . A comparison of n a t a l i t y rates i n white-footed mice for four years. J . Mammal. 3 7 : 5 1 3 - 5 1 6 . Davis, E. 1 9 3 1 . Some notes on mammals, birds and ferns of Kazabazua d i s t r i c t , Quebec. Can. F i e l d Nat. XLV: 193-194. Dice, L. R. 1 9 2 2 . Some factors a f f e c t i n g the d i s t r i b u t i o n of the p r a i r i e vole, forest deer mouse, and p r a i r i e deer mouse. Ecol. 3 : 2 9 - 4 7 . 1 9 3 1 . The occurrence of two subspecies of the same species i n the same area. J. Mammal. 1 2 : 2 1 0 - 2 1 3 . 1 9 3 3 . F e r t i l i t y r elationships between some of the species and subspecies of mice i n the genus Peromyscus. J . Mammal. . 14: 2 9 8 - 3 0 5 . 1 9 3 7(a). F e r t i l i t y r e l a t i o n s i n the Peromyscus leucopus group of mice. Contrib. Lab. Vert. Genetics. Univ. Mich. 4 : 1 - 3 . 61. Dice, L. R. 1937(b)- V a r i a t i o n i n the wood-mouse, Peromyscus leucopus noveboracensis, i n the northeastern United States. Occas. Pap. Mus. Zool. Univ. Mich. 3 5 2 : 1-32. 1940. Ecologic and genetic v a r i a b i l i t y within species of Peromyscus. Amer. Nat. 74: 212-221. 1947. Effectiveness of s e l e c t i o n by owls of deer-mice (Peromyscus maniculatus) which contrast i n colour with t h e i r background. Contrib. Lab. Vert. B i o l . Univ. Mich. 34: 1-20. , and H. J . Leraas. 1936. A graphic method for comparing several sets of measurements. Contrib. Lab. Vert. Genetics. Univ. Mich. 3: 1-3-Downing, S. 1948. A p r o v i s i o n a l c h e c k - l i s t of the mammals of Ontario. Roy. Ont. Mus. Zool. Misc. Publ. 2. Eskridge, P. S. and R. H. Udall. 1955- The e f f e c t of cold starva-t i o n upon carbohydrate reserves i n Peromyscus maniculatus. J . Mammal. 36: 139-140. Foster, D. D. 1959. Differences i n behavior and.temperament between two races of the deer mouse. J . Mammal. 40: 496-513-Fox, W. 1948. V a r i a t i o n i n the deer-mouse (Peromyscus maniculatus) along the lower Columbia River. Amer. Midi. Nat. 40: 420-452. Getz, L. L. 1961. Notes on the l o c a l d i s t r i b u t i o n of Peromyscus  leucopus and Zapus hudsonlus. Amer. Midi. Nat. 65*- 486 - 5 0 0 . Ginsburg, I. 1939- The measure of population divergence and m u l t i p l i c i t y of characters. J . Wash. Acad. S c i . 2 9 : 317-330. H a l l , E. R. and K. R. Kelson. 1959. The mammals of North America. The Ronald Press Co., N. Y. 1083 PP- (Vol. II, pp. 6OI-658). Hamilton, W. J., J r . 1941. The food of small forest mammals i n eastern United States. J . Mammal. 22: 250-262. Hedlger, H. 1949. Saugetier-Territorien und lhre Markierung. Bijdragen tot de Dlerkunde. 28: 172-184. (In Bourliere, 1956). Hoffmelster, D. F. 1951. A taxonomic and evolutionary study of the pihon mouse, Peromyscus t r u e i . Univ. 111. B i o l . Monog. 21: 1-104. Hooper, E. T. 1957* Dental patterns i n mice of the genus Peromyscus. Misc. Publ. Mus. Zool. Univ. Mich. 9 9 : 1-59-1958. The male phallus i n mice of the genus Peromyscus. Misc. Publ. Mus. Zool. Univ. Mich. 105: 5-24. Horner, E. B. 1954. Arboreal adaptation of Peromyscus with special reference to the use of the t a i l . Contrib. Lab. Vert. B i o l . Univ. Mich. 61: 1-84. 6 2 . Howard, ¥. E. 1951• Relation between low temperature and a v a i l -able food to su r v i v a l of small rodents. J . Mammal. 3 2 : 3 0 0 -3 1 2 . 1 9 6 1 . Seeds stored by p r a i r i e deer mice. J . Mammal. 42: 260-263. Hubbs, G. L. and C. Hubbs. 1 9 5 3 . An improved graphical analysis and comparison of series of samples. Syst. Zool. 2 : 4 9 - 5 7 * , and K. Kuronuma. 1 9 4 1 . Analysis of hyb r i d i z a t i o n i n nature between two species of Japanese flounders. Pap., Mich. Acad. S c i . Arts,Letters. 2 7 : 2 6 7 - 3 0 6 . , B. ¥. Walker, and R. E. Johnson. 1 9 4 3 . .Hybridization i n nature between species of American Cyprinodont f i s h e s . Gontrlb. Lab. Vert. B i o l . Univ. Mich. 2 3 : 1 - 2 1 . , and R. L. Whitlock, I 9 2 9 . Diverse types of form develop-ment i n a single species of f i s h , the Gizzard Shad. Pap., Mich. Acad. S c i . Arts, Letters. 1 0 : 461 - 4 8 2 . Jackson, W. B. 1 9 5 2 . Populations of the wood mouse (Peromyscus  leucopus) subjected to the applications of D.D.T. and Parathion. E c o l . Monog. 2 2 : 259-281. Jameson, E. W., J r . 1943. NoteB on the habits and siphonapterous parasites of the mammals of Welland County, Ontario. J . Mammal. 24: 194-197. King, J . A. 1 9 5 8 . Maternal behavior and behavioral development i n two subspecies of Peromyscus maniculatus. J . Mammal. 3 9 : 177-190. Klein, H. G. 1959* E c o l o g i c a l relationships of Peromyscus  leucopus noveboracensls and P. maniculatus g r a c i l i s i n central New York. PhD Thesis. Cornell Univ. 101 pp. I960. E c o l o g i c a l relationships of Peromyscus leucopus noveboracensis and P. maniculatus g r a c i l i s i n central New York. E c o l . Monog. 3 0 : 387-407-Lack, D. 1 9 4 4 . Correlation between beak and food i n the cross-b i l l , Loxla c u r v l r o s t r a Linnaeus. Ib i s . 8 6 : 5 5 2 - 5 5 3 -1 9 4 7 . Darwin's finches. Cambridge Univ. Press. 162 pp. Lanko, J . L. I 9 6 0 . The i d e n t i f i c a t i o n of Peromyscus i n south-eastern Ontario. B.Sc. Thesis, Univ. B. C. 16 pp. Layne, J . N. and A. H. Benton. 1 9 5 4 . Some speeds of small mammals. J . Mammal. 3 5 : 103-104. Lindeborg, R. G. 1 9 5 2 . Water requirements of certain rodents from x e r i c and mesic habitats. Contrib. Lab. Vert. B i o l . Univ. Mich. 5 8 : 1 - 3 2 . 63. LInduska, J . P. 1950. Ecology and land-use relationships of small mammals on a Michigan farm. Game Divn. Dept. Conserv. Lansing, Mich. 144 pp. McCarley, W. R. 1954. Natural h y b r i d i z a t i o n i n the Peromyscus  leucopus species group of mice. Evol. 8: 314-323. Moore, R. E. 1961. Olfactory discrimination by indivi d u a l s of Peromyscus maniculatus and Peromyscus polionotus. B u l l . E c o l . Soc. Amer. 42: 86. Moreau, R. E. and H. N. Southern. 1957. Geographical v a r i a t i o n and polymorphism i n Chlorophoneus shrikes. Inst. F i s h . 125: 301-328. Osgood, W. H. 1909. Revision of the mice of the American genus Peromyscus. N. Amer. Fauna 28. 285 PP« Palmgren, P. 1932. Zur Blologie von Regulus r . regulus (L.) und Parus a t r i c a p i l l u s b o r e a l i s S r l y s . Eine verglelchende U. okologische Untersuchung. Acta Zool. fenn. 14: 1-113. Rand, A. L. 1945. Mammals of the Ottawa d i s t r i c t . Can. F i e l d Nat. 59: 111-132. Robbins, C. A. 1932. The advantage of crossed mandibles: A note on the American c r o s s b i l l . Auk 49: I59-I65.-Rowe, J . S. 1959. Forest regions of Canada. Can. Dept N. A f f a i r s , Natl. Resources, For. Branch. B u l l . 123. 71 pp. Rutter, R. J . 1951. Notes on the Peromyscus of Ontario. Can. F i e l d Nat. 65: 80-81. 1959. Homing mice. The B u l l . (Fed. Ont. Nat.) 84: 13-15-Saunders, W. E. 1907. A new mouse f o r Canada. Ottawa Nat. 21: 92. 1908. Extension of the range of Peromyscus michlganensis. Ottawa Nat. 22: 164. 1913. The p r a i r i e deer-mouse at London. Ottawa Nat. 26: 130. Schultz, L. P. 1937. Redescription of the Capelin, Mallotus catervanlus of the Western P a c i f i c . Proc. U. S. Natl. Mus. 85: 13-20. t and A. W. Welander. 1934. The Cottoid genus Hemllepldotus of the north P a c i f i c . J . Pan-Pac. Res. Inst. 9: 5-6. Sealander, J . A., J r . 1951- Survival of Peromyscus i n r e l a t i o n to environmental temperature and acclimation at high and low temperature. Amer. Midi. Nat. 46: 257-311-64. Sealander, J.A. J r . , 1952. Food consumption i n Peromyscus i n r e l a t i o n to a i r temperature and previous thermal experience. J . Mammal. 33 : 206-218. Sheppe, ¥., J r . I 9 6 I . Systematic and ec o l o g i c a l r e l a t i o n s of Peromyscus oreas and P. manlculatus. Proc. Amer. P h i l . Soc. 1 0 5 : 421-446": Snyder, L. L. and E. B. S. Logier. 1 9 3 0 . A faunal i n v e s t i g a t i o n of King Township, York County, Ontario. Trans. Roy. Can. Inst. XVIII: 167-208. 1 9 3 1 . A faunal Investigation of Long Point, and v i c i n i t y , Norfolk County, Ontario. Trans. Roy. Can. Inst. XVIII: 117-236. , T. B. Kurata, F. A. Urquhart, and J . F. Brimley. 1 9 4 1 . A faunal inves t i g a t i o n of Prince Edward County, Ontario. Roy. Ont. Mus. Zool. Contrib. 48: 1 - 1 2 3 . Standfield, R. 0 . 1 9 5 0 . A preliminary study of the mice of the genus Peromyscus i n the Toronto region. M.Sc. Thesis, Univ. Toronto. 81 pp. Svihla, A. 1 9 3 2 . A comparative l i f e h i s t o r y study of the mice of the genus Peromyscus. Misc. Publ. Mus. Zool. Univ. Mich. 24: 1 -39-Warburton, F. 1 9 4 9 . Notes on the mammals of Lion's Head, Bruce Peninsula, Ontario. Can. F i e l d Nat. 6 3 : 3 4 - 3 6 . Waters, J . H. I960. The post-Wisconsin r e d i s t r i b u t i o n of white-footed mice, genus Peromyscus Gloger, i n northeastern North America, with p a r t i c u l a r reference to Peromyseus leucopus  noveboracensis (Fischer). PhD Thesis, Univ. Conn. 113 PP; 1 9 6 2 . Range of Peromyscus maniculatus i n southern New England. J . Mammal. 4 3 : 1 0 2 . Williams, Olwen. 1 9 5 9 . Food habits of the deer mouse. J . Mammal. 40: 415-419. Wilson, L. W. 1 9 4 5 . The genus Peromyscus i n West V i r g i n i a . J . Mammal. 2 6 : 9 5 - 9 6 . Wirtz, V/. 0 . and P. G. Pearson. I960. A preliminary analysis of habitat o r i e n t a t i o n i n Microtus and Peromyscus. Amer. Midi. Nat. 6 3 : 131-142. Wright, A. H. and S. E. R. Simpson. 1 9 2 0 . The vertebrates of the Otter Lake Region, Dorset Ontario. Can. F i e l d Nat. XXXIV: 161-168. 

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