Life Underneath the Snow
Snow is such a good insulator that some animals in the Alps have evolved extraordinary strategies to use snow to keep them warm during winter;
- Small mammals, like voles and shrews, have an active existence in tunnels and corridors below the snowpack,
- black grouse are known to dig igloos to protect themselves from wintry conditions,
- and mountain hares simply stop moving when caught in a snowstorm to allow themselves to be covered by snow.
Several species of voles, such as the snow mouse (Chionomys nivalis) and the field mouse (Microtus arvalis) have extensive networks of corridors underneath the snowpack during the winter months. Such networks give the little critters the opportunity to move around freely in their search for food. The environment beneath the snow (the so-called subnivean zone) doesn’t only provide insulation, but also some protection from predators, such as owls and foxes.
The Eurasian shrew (Sorex araneus) also lives below the snow in winter. This little insect eater is as quick as lightning and loves eating worms, snails and all sorts of insects. Eurasian shrews have an exceptionally fast metabolism which means that when it’s cold and they’re short on food they can die within a few hours, despite the insulating effect of the snow.
The black grouse (Lyrurus tetrix) doesn’t build tunnels below the snow, but this medium-sized bird digs an igloo in the snowpack to protect itself from wintry conditions. Even during periods of mild temperatures, it likes to spend time snoozing in its self-dug hole.
The mountain hare (Lepus timidus) also uses snow as insulation during blizzards (see my previous blog). When surprised by a storm, the mountain hare remains motionless in the same spot. After a few minutes or hours, depending on how hard it snows, a small natural ‘igloo’ will form around the animal. Whilst waiting for calmer weather to arrive, a mountain hare, protected by its thick winter coat and a layer of snow, can sit motionless for hours without getting cold.
To be continued…
This blog is part of a series in which I discuss some of the extraordinary strategies and adaptations of wildlife coping with winter in the Alps: