HIBERNATION 151 



wings are folded along the sides. Sometimes the body rests against a 

 vertical surface and a pair of claws (they are really the animal's thumb 

 nails) on the wings help to support the weight. More often the ani- 

 mal hooks its claws to the rough stone ceiling of a cavern and does not 

 touch a solid support with any other part of its body. The body sways 

 gently back and forth as the animal breathes, and its breathing is rapid. 

 It is easily awakened by a touch, a noise or even by bringing the heat 

 of a candle near it. The parts that are not covered by hair feel warm 

 to the touch. 



The hibernating animal is found in the same locations and the same 

 attitude as the sleeping animal. It does not sway with a regular rhythm, 

 and if you give it a mere cursory examination you may be convinced 

 that it is not breathing. However, a longer observation will show that 

 at irregular intervals, perhaps minutes apart, it will respire in a con- 

 vulsive manner for a few times and then become quiet. It is not easily 

 disturbed by a noise or by warmth. If you rudely snatch it from its 

 place and then release it, the animal is absolutely helpless and falls to 

 the ground with wings still folded. The hairless parts of its body are 

 cold to the touch. 



However, a severe disturbance will arouse it, no matter how soundly 

 it sleeps or at what season it may be. It then begins to breathe, not 

 rapidly nor regularly at first, but with so much violence that it seems 

 as though the whole body will be torn to pieces. The wings and legs 

 move spasmodically and the temperature rises rapidly. In a few 

 minutes the bat is wide awake and active. Between the two extremes 

 of light sleep and deep torpor, every gradation exists. 



Between April and August bats rarely enter the caves. During 

 this period they rear their young, spending the days in trees and out-of- 

 the-way nooks and crannies, and the nights in chase of insect food. 

 Some time during August they begin to return to the caves in consid- 

 erable numbers, and during this month I have found many of the ani- 

 mals as torpid as at any time during the year. In every instance the 

 torpid animals were exceedingly fat. This should not be understood as 

 implying that these creatures remained in this condition without taking 

 food until April. Indeed I am very certain that this was not the case, 

 but the reasons for so thinking will be developed later. 



By the first of October it is probable that all of the bats have de- 

 serted their colder outdoor retreats and have come into the caves, but 

 even now all do not remain continuously, but some go out to search for 

 food when the nights are not too cold. I have not seen them out later 

 in the season than the middle of November, but it is not improbable 

 that some may venture out at any time during the winter if balmy 

 nights occur. 



During the late autumn the greater number are found in the large 



