Not much is known of their life histories on this continent. They are mainly nocturnal and live in burrows from two to three feet long, ending with a nest chamber four or five inches in diameter, warmly lined with grass and moss. Near the nest there is usually a branch burrow a foot or more long which is used for sanitary purposes and as a place of refuge when the main burrow is invaded.
In the nests during early summer litters generally containing about three young are brought forth. Ordinarily the burrows open in unsheltered places, but in wooded regions may be under a log or beneath a bush or the roots of a tree. No runways lead out from the burrows as is customary with many of their relatives. They are active throughout the winter, making many tunnels along the surface of the ground under the snow, which are revealed when it melts in spring.
These surface tunnels are their foraging roads, safe from most of the fierce storms which rage overhead. At times, however, the snowy shelter is blown away or some other cause brings the lemmings to the surface, where they blunder aimlessly about, soon to be captured by some enemy or to perish from the cold. As their infrequent appearance on top of the snow is usually during storms, the Alaskan Eskimos have a legend that these white lemmings live in the land above the stars and descend in a spiral course to the earth during snowstorms.
Although banded lemmings never become so extraordinarily numerous over great areas as the brown species, they become very abundant at times in the barren grounds of Canada and the Arctic islands and migrate from one part of their range to another. The best observation in regard to this was made by Rae in June at the mouth of the Coppermine River. On the west bank of the river north of the Arctic Circle he encountered thousands of them speeding northward.
The ice on some of the smaller streams had broken up and he was amused to see the little animals running back and forth along the banks looking for a smooth place in the stream, indicating a slow current, where they could swim across. Having found such a place, they at once jumped in and swam quickly to the opposite side, where they climbed out and, after shaking themselves like dogs, continued their journey as though nothing had happened.
During the years I lived in northern Alaska the advent of winter was marked by invasion of the storehouses by many brown lemmings and other mice, but banded lemmings rarely appeared. When occasionally captured alive, the old ones fought viciously, but the young were gentle and quickly became tame and interesting pets. Their skins were highly prized by the little Eskimo girls to make garments and robes for their walrus ivory dolls.
THE BROWN LEMMING (Lemmus alascensis and its relatives)
(For illustration, [see page 579])
Few small mammals are so well known in far northern lands as the brown lemmings. They form a small group of species having a close general resemblance to some of the field mice, from which, however, they may at once be distinguished by their much heavier proportions, extremely short tails, and the remarkable length of the hair on their backs and rumps.
They inhabit most of the arctic and subarctic lands of both Old and New Worlds. In North America they are known from the northernmost lands, beyond 83° north latitude, to the southern end of Hudson Bay, and throughout most of northern Canada and all of Alaska, including the islands of Bering Sea.