Keeping Warm Under a White Blanket
Another adaptation for many plants and animals is to make the most of a blanket of snow. Air is trapped amongst the snow flakes as they fall and this provides good insulation. The temperature under a layer of snow does not usually fall below freezing. The heat from any animals or plants under the snow is trapped in a warm ‘igloo’. Small mammals such as mice, voles and lemmings can remain active throughout the winter, searching for plant food in a network of tunnels under the snow. The polar bear digs out a den on snowy slopes to give birth or shelter during blizzards. It curls up and lets the snow drift around its body to form an insulating layer.
Many plants also survive in warm pockets under the snow, waiting for the snow to melt so they can then burst into growth. If winds blow the snow away they may become frozen.
A local name for the familiar snowdrop is the ‘snow-piercer’. The tip of the flowering stem is covered by a special protective leaf and this allows the snowdrop flower to force its way up through the snow.