Page:Popular Science Monthly Volume 84.djvu/155

Rh 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 animal 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 convulsive 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 considerable numbers, and during this month I have found many of the animals 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 deserted 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