HIBERNATION 357 



Earlier or later in the autumn, according to the species, the bats 

 retire to caves and hollow trees and similar places, where they cluster 

 together, hanging by their hind claws, head downward, and clinging 

 to one another as well as to the walls of their retreat. Such masses may 

 comprise various species, yet all species do not retire at the same time. 



The noctule is seldom seen abroad later than July — while the pipis- 

 trelle may be seen flying any warm evening during the spring, summer 

 and autumn months. 2 



Owing to the difference in the flying season of these different bats, 

 it is only natural to suppose that the hibernation of the former species 

 (noctule) is much deeper and longer than in the latter (pipistrelle), 

 which may feed all the year round. Here in North America some bats 

 may, and probably do, migrate southward to avoid the too intense cold, 

 and among these is probably the noctule, which is the first to come and 

 the first to go. 3 These " flitter mice " 4 are insectivorous, and before 

 discussing some of the other mammalia, it may be advisable to call 

 attention to some points of difference existing, during the hibernating 

 state, between the carnivorous and herbivorous animals. 



Bears come out of the hibernating condition as fat, or nearly so, 

 as when they retired in the fall ; marmots, ground squirrels, etc., emerge 

 in poor condition, in some cases quite emaciated; this in spite of the 

 fact that they are functionally torpid, while bears and skunks are not. 

 Female bears even bring forth their young while hibernating and suckle 

 them from about the beginning of February to April, while they obtain 

 no nourishment themselves. 



The bear and badger, in our northern and western climates, retire 

 to their winter quarters and pass the greater part of their time in sleep, 

 yet neither the brown bear 5 nor the badger falls into a true state of 

 hibernation. On the other hand, the black bear of North America is 

 aroused with difficulty from his winter sleep, and this gives ground for 

 the belief that he differs from the other species of bears in that he 

 hibernates while the others do not. 



The most perfect hibernating animal we have in Canada is the 

 ground-hog (woodchuck), which hibernates in a burrow of its own 



2 These names — noctule and pipistrelle — are the common names of two 

 species of European bats; the genus Pipistrelle is represented in North America, 

 but only in the extreme southern portion of the United States, by three species 

 and two subspecies. The common bats of eastern North America are the hoary, 

 brown, silvery, red and the little brown bat, all of which are found here in 

 British Columbia except the red variety. 



3 Bats undoubtedly migrate; see Miller, "North American Fauna," No. 13. 



4 Old term. 



6 The " brown bear " is a very loose term — the cinnamon bear is only a 

 color phase of the common black bear. The grizzly may be any color and are 

 eubgenerically distinct from the black bear. It is doubtful if any bear is 

 completely torpid during hibernation; the grizzly is much less so than the black 

 bear, the period of hibernation being shorter. 



