their enemies, they took to eating more and more from the pantry shelf, and thus the members of the family that were the busiest and, therefore, had the most to eat would naturally survive and leave children of a similar disposition, while the less thrifty would die off. III. THE LONG WINTER SLEEP Some of these forehanded people, instead of putting their Winter supply of food in the ground, put it on their bones. That is to say, before turning in for the Winter, they get as fat as can be and then live on this fat until Spring. A great advantage of this system of storage is that it is particularly pleasant work--you eat and eat and enjoy your meals, that's all. Another advantage is that you can't be robbed of your store as easily as the hamster, for example, frequently is. You carry it right with you wherever you go. There are a lot of curious things about this hibernation. Not only will warmth arouse the sleepers but also extreme cold, and after the extreme cold may come another sleep from which the sleepers never awaken; in other words, too much cold kills them. So the object of burying one's self as the ground-hog does, or under the snow as rabbits do, or in hollow caves and trees as Brer Bear does, is to keep from getting too cold. Sometimes two or more "bunk" together, as little pigs do on cold March days. The body of each helps to keep his bedfellows warm. IT'S THE COLD THAT MAKES ONE DROWSY It is the cold itself that seems to make hibernating animals feel sleepy; just as it does human beings. At a moderate temperature, say 45 or 50 degrees, dormice and hedgehogs will wake up, eat something, and then go to sleep again. The dormouse usually wakes in every twenty-four hours, while the hedgehog's Winter naps are two or three days long. Hunger seems to be the cause of their waking, just as it is with babies. The little dormouse, as the air grows colder, gradually dozes off, and his breathing is very deep and slow. As the temperature rises, he begins to take shorter and more rapid breaths and gradually wakes up. Then, if he is in his own little home under the ground, he feeds on the nuts and other foods that he stored in Autumn and drops off again. He sleeps from five to seven months, depending on the weather. Moles and shrews, so far as observation goes, don't hibernate. The moles simply dig deeper, and there they find worms and insects that are buried away from the reach of frost. The shrews hunt spiders and hundred-legged worms and larvæ in holes and crannies of the soil or beneath leaves of ground plants and old logs. [Illustration: LITTLE HEDGEHOG IN MAN'S HAND]