Animals in Winter

We enjoy seeing the world around us transformed by snow and ice. We go for walks in the crisp winter air, while children build snowmen, go sledging, zoom down slopes on skis or skate across frozen surfaces.

When we get too cold, we retreat to our heated homes and flats. But winter is a tough time for animals living in the wild. The cold often isn’t even the biggest problem. Above all, there’s very little food to be found.

But nature knows how to cope with these challenges, too. All living things are adapted to their habitats, including winter conditions. The animals that stay here for winter get through this difficult time in different ways.

Birds have two strategies. Some species leave us in good time in autumn. They fly to countries around the Mediterranean or to Africa. These include starlings, swallows and storks, for example. They are called migratory birds. They find plenty of food in warmer countries, but need a lot of energy to cover the long distances.

But some birds spend the winter here, too. We call them resident birds. Examples include blackbirds, tits, chaffinches and robins.

In autumn, they grow a dense layer of feathers to keep warm. But it is still hard for them to find enough food when snow and ice cover everything. That is why they often visit feeding stations set up for them by people in winter.

Horses, ponies, sheep and cattle usually spend the winter in a sheltered barn. But in autumn they grow a thick winter coat, so they can also be kept in an open-sided barn. Wild horses and some breeds of cattle can live outdoors in winter, too.

Their winter coats protect them from temperatures as low as about minus 20 degrees Celsius. In winter, however, the animals need more food and water than at other times of the year because their energy requirements are much higher. Outdoors, they also need shelter from the icy wind.

Hedgehogs do it like this: During summer and autumn, they build up a layer of fat. Then, in October or November, they find a sheltered spot under a pile of wood or leaves and go to sleep. Their body temperature drops to 4 degrees Celsius. This means they use so little energy that their fat reserves last until spring.

Hedgehogs can go for up to six months without food. However, they lose 20 to 40 percent of their weight during hibernation. If they weigh 1,000 g in autumn, they weigh only 600 to 800 g in spring.

Other animals that hibernate include marmots, bats, dormice and hazel dormice. They also lower their body temperature to just a few degrees. In winter, their hearts beat very slowly and they breathe only occasionally. Animals that do not hibernate move around as little as possible in winter.

Squirrels build a nest called a drey in a hollow tree stump or in the fork of a tree. A drey is about half a metre wide, has an interior space of around 20 cm and is lined with moss and grass. It has an entrance underneath and a roof to keep the inside dry.

Squirrels spend most of the winter asleep in this drey. They also grow a thick winter coat in the fall and eagerly gather acorns, beechnuts, cones, and nuts, which they bury in different places. When they wake up in winter, all they have to do is find their stashes and they can eat their fill.

Although squirrels sleep a lot, they wake up several times, so we say they go into winter dormancy rather than hibernation. Other mammals, such as badgers, European hamsters and moles, also go into winter dormancy.

As soon as it gets colder outside, frogs, toads and lizards seek out a sheltered place. As temperatures drop, they enter a state of torpor. The animals stop moving and their body temperature falls to match the temperature around them.

They breathe very rarely, and their hearts beat only a few times per minute. They just need to get to a place where they are protected from frost in time. Otherwise, their bodies, which are partly made of water, would freeze and be damaged. Frogs, for example, retreat to the bottom of a pond.

Some insects and snails also hibernate, as do native snakes such as the grass snake. They like to spend the winter under a pile of leaves or in a mouse hole.

Bees spend the winter in their hive. At this time, a colony consists of several thousand worker bees and a queen. In summer, worker bees live for only 6 weeks, but in winter they live for 6 months.

When it gets cold, bees huddle tightly together in their hive. Each bee clings to the others and moves its flight muscles. This forms a winter cluster. Like all living things, bees give off heat. The physical effort makes them give off even more heat, warming the inside of the cluster considerably. The temperature can rise to as high as 30 degrees Celsius.

The queen sits right in the middle. She must survive at all costs. The workers change places from time to time. That way, each one gets a turn in the middle, and they can also endure the cold at the edge of the cluster for a short while.

Ladybirds seek shelter under leaves, moss, wood or stones. Their bodies contain a fluid that keeps them from bursting in freezing temperatures—like built-in antifreeze.

This allows them to withstand temperatures as low as about -15 degrees Celsius. They also spend the winter in large groups. That way, they can find a mate easily in spring without having to search for long. It takes less effort and saves energy.

In winter, they live off fat and other substances they have stored in their bodies.

Fish adjust their body temperature to the temperature of the water. When it is warm, the fish’s body is warm too. When the water gets colder, the fish’s body temperature drops. Fish also move only as much as necessary in winter to save energy. In autumn, they build up some fat, which they now live off. During the cold season, they stay in the depths of bodies of water and wait for spring. The tench even hibernates in the mud.

Most butterflies die before winter begins. Some species, however, overwinter as adults, including the brimstone butterfly and the peacock butterfly. They hide in hollow trees or in the nests and burrows of other animals.

There they remain completely still. However, most species spend the winter as caterpillars, pupae or even just eggs. They can be found in small crevices, inside hollow plant stems, or stuck to a tree or house wall.

You can help these animals by providing an “insect hotel”. The various species can spend the winter in the hollows of different sizes.

Some caterpillars have a clever trick: the caterpillar of the scarce large blue, for example, lets ants capture it and carry it off to their protective nest. In return, it occasionally secretes a sweet drop that the ants love.