A queer thing is that the hedgehog, which belongs to the same family as the shrew and the mole, is dead to the world all Winter. Like all complete hibernators he stops breathing entirely. The reason for this difference between the hedgehog and the mole is that the mole doesn't need to go to sleep, because he digs below the frost-line. As for the shrews, they have little bodies and are very active, and so get themselves food and keep warm, while the hedgehog is so much bigger and slower that, when there is so little to eat and it is so cold, he would either freeze or starve to death if he went about looking for food. He finds it cheaper to turn in and sleep than to work. [Illustration: A HEDGEHOG AND HER BABIES] None of the tree-squirrels seem to take any unusually long naps in the Winter. We often see them around on pleasant days in the parks and in the woods. They run out, get a few nuts from their stores, and then back again to their nests, but the chipmunks and the gophers, who are closely related to the squirrels, stay from late Autumn to Spring in their burrows, where they have plenty of food stowed away, and they sleep most of the time. In the home of four chipmunks was found a pint of wheat, a quart of nuts, a peck of acorns, and two quarts of buckwheat, besides a lot of corn and grass seed; all to feed four fat chipmunks. So, with such plentiful supplies, it is not surprising that after their long Winter sleep the chipmunks are as sleek as can be and as fat as butter, while Mr. Bear comes out in the Spring lean and with his hair all mussed up and as hungry as--well, as hungry as a bear! All the bear family, except the polar bears, retire to caves or some sheltered spot under a ledge of a rock or the roots of a big tree. Among the polar bears the rule seems to be that it's Mamma Bear only who goes to bed for the Winter. She is careful to put on enough fat not only for herself, but so that the babies that come along in the Spring will have plenty of milk. She is buried by snow that drifts on her and her breath melts a funnel up to the fresh air. IV. MR. GROUND-HOG AND HIS SHADOW