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Where do animals go during the long, cold, dark winter?
If the long winter nights make you want to sleep forever, curl up or head somewhere warmer, you're not alone. Winter is a time where many animals conserve their energy, fly south or grow a thicker coat.
Winter is a challenging period for some of the UK's wildlife, especially for those that are small. Food is scarce, temperatures are low and animals need to conserve the energy they have to survive.
Not all animals hunker down. Some grow a dense winter coat, others migrate to warmer climes where food is easier to find and the odd few even shrink their bodies to get through the leaner months.
Hedgehogs build nests
A hedgehog in its winter nest. © Petr Bonek/Shutterstock
Hedgehogs, Erinaceus europaeus, often choose leaf litter and logs as places to build their nests, using dry leaves, grass and other vegetation to help keep out the cold.
To make sure they have enough body fat to last the winter, they must consume enough food before the cold weather arrives. Young hedgehogs usually need to reach a body weight of around 500 grammes or more to survive the colder months - that's about the weight of a loaf of bread. Hoglets born late in the year can struggle to put on enough weight to see them through the winter.
The start and end of their hibernation season depends on the weather, but hedgehogs are usually inactive between November and mid-March.
Dormice settle in for the winter
Dormice curl their tails over their faces when dormant and sometimes even snore. © Kurkul/Shutterstock
The hazel or common dormouse, Muscardinus avellanarius, spend a long time being dormant. They are usually inactive between November and April, although sometimes they don't wake up until May. This long dormancy is likely why their name is derived from the French word 'dormir' and the Latin word 'dormire', meaning to sleep.
These tiny rodents live in woodlands, hedgerows and scrub and are mostly found in the south of the UK. In summer, they sleep during the day and are active at night, roaming around looking for berries, insects and nuts. They are currently classed as endangered.
Shrews and moles shrink themselves to save energy
In winter, this shrew will shrink in size by as much as 20%. © Rudmer Zwerver/Shutterstock
Shrews and moles have a remarkable way to get through winter - they shrink themselves. In fact, shrews, Sorex araneus, can even shrink their skulls by as much as 20%, and they don't stop at the bones, they also shrink their organs and brain too.
In winter, shrews spend less time running around and more time eating, drinking and walking. Shrews use so much energy that they are constantly in need of food. If they don't find any food for two hours, they could die.
Moles, Talpa europaea, also shrink themselves, sometimes by up to 11% to save on energy. When the weather warms up, shrews and moles will expand their bodies and grow again.
Bats save energy over winter
Bats in the UK spend winter saving on energy and being inactive. © Martin Janca/Shutterstock
All of the UK's bat species hibernate. Some stop being active in November, but most will be inactive from December through to at least March. If the weather gets colder once they've become active again, they might enter a state known as torpor.
Like hibernation, torpor also involves reducing body temperature and metabolism to save energy, but it occurs over shorter periods, such as overnight. By May, bats will be fully active again.
Snakes and reptiles slow down
Adders don't do all that much when it's cold. © Jamie Hall/Shutterstock
Snakes and lizards are mostly inactive during the winter in the UK. At this time of year sunlight doesn't provide them with the warmth and energy they need, so they slow down and spend the winter months in a sheltered spot, barely moving.
These reptiles might choose leaf litter, rock crevices or even an old tyre as their winter home.
Swallows fly south to warmer climes
Swallows leave the UK in autumn. ©Alex Cooper Photography/Shutterstock
If you can fly away to a warmer place, why wouldn’t you? Swallows do just this, spending their summers in the UK and then packing up and flying south when it starts to get cold.
Swallows from the UK spend around six weeks making the long journey south to Namibia or South Africa. You can see where swallows spend their time in this map of found, tagged swallows.
Unlike the swallow, other birds, including some geese, actually arrive in the UK for winter, as it's warmer than their summer homes in Scandinavia or the Arctic.
