Winter in the mountains can be tough for animals. Colder temperatures, shortened daylight hours, and lack of food can make it pretty hard to survive. They have to use energy to keep warm at a time when food is scarce. So how do they do it?
Some animals hibernate in dens to avoid the extreme cold temperatures of the coldest months of the year.
Marmots take hibernation to the extreme (6-9 months). As soon as daily temperatures drop below 12 degrees Celsius, alpine marmots will hide in their underground burrows. Their hibernation starts at the end of September, and they’ll wake up six months later, at the end of March, missing all the difficult winter days.
At the end of the summer they gather old stems and grass in their burrows to make bedding for their hibernation.
Marmots will huddle next to each other and begin hibernation, a process that lowers their heart rate and breathing, which uses up their stored fat supplies slowly, and usually allows them to survive the winter.
Hibernation is remarkably efficient; marmots burn almost nothing.
A marmot’s sleep in hibernation is so deep that you won’t be able to wake it up, even if you tried!
Once the snow melts, marmots eat. They must double their mass during the year to ensure survival through the next winter.
Other mammals hibernate in winter, such as hedgehog and dormice. Hedgehogs prefer to stay outside, while dormice prefer to sleep in sheltered places such as old barns, stables or even people’s houses.
Some animals’s fur and feathers turn white in winter, giving them an incredible camouflage and making them incredibly difficult for predators to spot.
Although various shades of brown in summer, mountain hares turn white for winter.
As well as changing colour, a mountain hare grows extra hairs on its paws to make the surface of its feet bigger and prevent the hare from sinking into the snow.
Its insulating winter coat also proves to be very useful during a snow storm. In a blizzard, in fact, a mountain hare remains motionless in the same spot. By doing so, a small natural ‘igloo’ will form around the animal. This way the snow hare, protected by a layer of snow and its thick winter coat, can wait motionless for hours for calmer weather to arrive without getting cold.
The grey-brown summer feathers turn into a much more reddish-brown color in autumn, and transform into a bright white when the snow begins to fall, so the bird can blend in with the snow. A further molt in the spring precedes the breeding season.
Legs and toes insulated by feathers, feet so feathered that act as snowshoes to stay afloat in the deep snow.
The bird’s diet varies seasonally. Flowers, blooms and berries form the majority of the ptarmigan’s diet in the summer. Once winter arrive, the ptarmigan feeds on shoots and buds.
Another animal that turns white in winter is the stoat. All three species keep a small black tuft which they use for communicating with each other. Both stoats and rock ptarmigans have black tips on their tails, while a mountain hare has black tips on its ears.
Snow as insulator
Snow is such a good insulator that some animals in the Alps have evolved extraordinary strategies to use it to keep them warm during winter.
Voles ans shrews
Voles have extensive networks of corridors underneath the snow pack during the winter months.
Such networks give them the opportunity to move around freely in their search for food. This environment underneath the snow doesn’t only provide insulation, but also some protection from predators, such as owls and foxes.
Shrews also lives underneath the snow in winter, where they can hunt for worms, snails and all sorts of insects.
The black grouse digs an igloo in the snow pack to protect itself from wintry conditions. Even during periods of mild temperatures, it likes to spend time snoozing in its self-dug hole underneath the snow.
Food is scarce during the winter, but some animals are wise enough to collect food when there is plenty and save it for the cold season. For this reason, autumn is a busy time for these animals.
Squirrels don’t hibernate, but they store fungi and other food inside of trees to eat over the winter. They sleep during colder periods, but come out on warmer days to retrieve the food they collected through the autumn. They’re usually solitary, but they might share a nest for warmth.
Like all birds, nutcrackers need a lot of energy to keep warm during cold winters.
A single nutcracker buries thousands of seeds and nuts in the autumn.
Nutcrackers have incredible memories and recall exactly where they have buried all their nuts and seeds. They remember the exact angle of their flight from a tree branch to a hiding place, which allows them to retrieve their stashes even from underneath a thick layer of snow.
They bury more seeds and nuts than they can eat, so many seeds and nuts stay buried. In this way, they contribute to the planting of new trees in the forest.
As well as animal migrating south, those that remain in our mountains also migrate: they descend to lower altitudes in search for higher temperatures and a thinner snowpack.
Winter is a stressful time for red deer, grasses and dwarf shrubs are covered in snow and nearly inaccessible to them.
They spend all winter in a small territory in the woods. They move as little as possible. Staying inactive conserves energy and nutrients.
They eat dried plant materials, such as leaves, lichen and tree bark, which are relatively low in nutrients.
In order to adapt to the extreme situations that come with changing seasons, red deer have learned to “shrink” their digestive tract and extract nutrients from food more efficiently.
Used to live in cold, highland terrain like Alpine meadows above 1800 meters (summer).
As winter approaches, they wander down to lower altitudes, where they stay on steep slopes where snow does not accumulate, and sometimes may enter forested regions.
While in the summer chamois can feed on a diet of herbs and flowers, during winter they turn to lichens, mosses, buds and shoots of shrubs, conifers and deciduous trees.
The list of animals that descend to lower ground to seek protection also includes (among others) wild boar, red foxes, hares and alpine marmots.
However, there is one bird species that stays high up even in the harshest of winters: the Alpine chough. They might descend to lower altitudes to find food, but when they are done these birds will always return to their alpine habitat.