The most unusual of all the underground and basement dwellers is the polar bear. This wise inhabitant of the Far North has long ago learned that no animal needs to freeze to death in the snow. To him the snow is a constant means of warmth and protection, and as winter approaches, he seeks a position, usually near a big rock, where he digs out a hole of small dimensions, and allows the snow to cover his body. Strangely enough it is only the female bear that seeks this permanent snow hut; the males do not care to spend so much time in seclusion. The same is true of the unmated females. But the mated females always have snow huts in which they give birth to their young, and where they reside until early spring; then the mother bear comes forth with them to seek food and teach them the ways of the world.
American Museum of Natural History, New York
TO THE POLAR BEAR THE ICE AND SNOW OF THE FAR NORTH MEAN WARMTH AND PROTECTION. THE MOTHER BEAR DIGS HERSELF INTO A SNOWBANK, WHERE SHE LIVES QUITE COMFORTABLY THROUGHOUT THE WINTER.
THE SHARP CLAWS OF THE GROUND SQUIRREL ARE EFFICACIOUS TOOLS IN DIGGING HIS COSY UNDERGROUND BURROW.
There is no danger that the bears will stifle for air under the snow, because the warmth of their breath always keeps a small hole open at the top of the snow-cell. This snow-house increases as time goes on, the heat exhaled from their bodies gradually melting the snow. Often Mrs. Bear's home is discovered by means of the tiny hole in the roof around which is collected quantities of hoar frost.
Hibernation is one of the strangest phenomena of the animal world, and bears, especially the white bear of the polar regions, the black bear of North America, and the brown bear of Europe, agree in the curious habit of semi-hibernation. In the late fall of the season, the bears begin to eat heavily and soon become enormously fat, preparatory for the long winter of semi-sleep.