Life Under the “Blanket”

Darting about through networks of tunnels just beneath the snow may be any number of tiny, furry animals going about their daily business, a large part of which is often a frenetic search for food. They include lemmings, voles, and shrews​—small, chiefly nocturnal insectivores related to moles. Mice, on the other hand, can often be seen scurrying about on the surface of the snow in search of berries, nuts, seeds, and the soft outer bark of young trees.

How do smaller mammals maintain the right body temperature? Many have not only a warm winter coat but also a built-in furnace in the form of a rapid metabolism. As you can imagine, these living heaters need lots of fuel. Shrews, for instance, eat close to their own weight in insects, larvas, and pupas each day. Proportionately, the smallest species​—the pygmy shrew—​eats even more! Therefore, practically every waking moment is filled with a relentless search for food.

The many tiny mammals, in turn, are high on the menu of predators, including the owl and two members of the weasel family, the ermine and the least weasel. Slender and agile, weasels are well equipped to negotiate snowy, hidden labyrinths in their quest for food. Weasels even hunt rabbits, which exceed them in size.

So that they do not starve during the lean winter season, many animals tap into fat reserves accumulated during the warmer months. Some food, though, is usually available. For example, moose nibble the young branches of trees, especially pines. Squirrels dine on nutritious seeds hidden in their larders, and hares gnaw on young bark, twigs, and shoots.