Every animal must develop its own way of dealing with winter. Migrate, hibernate, or insulate; these are common strategies. For a few small mammals, survival depends on the snow itself, and the deeper the better.
The subnivean zone is the area between the surface of the ground and the bottom of the snowpack. The word subnivean comes from the Latin “sub” (under) and “nives” (snow). Mice, voles, and shrews retreat here for protection from cold temperatures, bitter winds, and hungry predators. Food is right at hand: grass, leaves, bark, seeds, and insects are free and unfrozen. Under the snow, these tiny mammals create long tunnel systems complete with air shafts to the surface above. » Continue Reading.