Section IV., 1892. [ 49 J Trans. Roy. Soc. Canada. 



\Y .—HiberinUion ami Allied Stoics in Animals. 



By Wesley Mills, M.A., M.D., F.K.S.C, Professor of Physiology iu McGill University, 

 ^ Montreal. 



(Ko:id .luno Isl, 1892.) 

 I. 



For a long tlmt- it has been known that many insects pass into a state of profovincl 

 torpor during the winter season from which they are apt to emerge, as seen in our house 

 flies, when the temperature rises sufhcieutly high. 



Snails are well known to provide against the approach of winter by closing up their 

 shells within which they sink into a protective sleep, and doubtless hibernation is a very 

 widespread phenomenon among invertebrates. 



There seems to be little doubt that in cold latitudes all reptilia and amphibia hiber- 

 nate, and in warm countries œstivate. Nevertheless, definite investigations have been 

 few. At the Philadelphia meeting of the American Association for the Advancement of 

 Science of 1884, A. W. Butler made an interesting communication on this subject, giving 

 some definite data, more especially in regard to the hibernation of the " box tortoise," 

 " soft-shelled " and " hard-shelled " turtles, frogs, toads, newts, salamanders and certain 

 fishes, \^■hich may be found stated succinctly in the proceedings of the Association for that 

 year. His observations apply to Brookville, Ind., U. S. A. He concludes that " in this 

 part of the Ohio Valley, tortoises, turtles, toads and frogs are regularly found hibernating ; 

 while on the other hand newts, salamanders and many species of fish do not as a rule 

 enter a torpid state." 



There seems to be no doubt, however, that many species offish do hibernate. Turn- 

 ing to warm blooded animals (homoiothermers) it is thought that while the brown bear 

 of Europe and the badger sleeiD most of the time in winter, they do not hibernate in the 

 same sense as, e.g., the dormouse. The black bear is believed to hibernate, though definite 

 inibrmation about the winter life of this creature and other American bears generally 

 would be very welcome. The hedgehog is regarded as a true hibernater the winter long. 

 It is known that the tenrec of Madagascar sleeps for three mouths in his burrow during 

 the hottest part of the year. It is, however, among the rodents that we must look for the 

 most perfect hibernation ; and the porcupine, the hamster, the dormovise, the marmot — 

 and as some think the squirrels are the best known examples. But if the hibernation of 

 the bat is not the most perfect, it seems to have been about the best studied, for Marshall 

 Hall's investigations of sixty years ago are still to be regarded as classic. 



In consequence of reference to this subject in a paper on squirrels read before the 

 Society iu 1887, and my appeals for assistance in the study of this wide subject (in which 

 one person can do comparatively little of himself, at least in ascertaining those modifica- 



Sec. IV., 189L'. 7. 



