Which Animals and Insects Hibernate in the UK?
Posted on January 03, 2020
What is Hibernation?
During the winter many animals struggle to survive, battling the cold, wind & rain and food is much harder to find. Hibernation is like sleeping; some animals can slow their heartbeat and breathing rate down, they also lower their body temperature, and enter a state of 'Torpor' (state of physical and mental inactivity). Animals and insects do this so they use less energy and are able to survive weeks without food. Before animals hibernate they will eat as much as they can to fatten themselves up over the winter period. Insects replace water in their bodies with glycerol, which acts like anti-freeze.
Animals, Reptiles & Insects
Hedgehogs will usually hibernate from October/November through to March/April. They may sometimes be seen out and about as they move nesting sites at least once during this time. If we have a mild winter you may even see them in December. During this time they will eat and drink as much a possible, searching for their natural foods (slugs, beetles, worms and caterpillars). Putting water and food out in your garden will help as their usual food is sometimes hard to find as winter creeps in. One thing to remember is Never feed a hedgehog milk, it gives them diarrhoea. Leave out crushed cat or dog biscuits or tinned meat (not fish) instead.Hedgehogs like to nest in piles of leaves or an overgrown area of your garden, a garden waste pile maybe.
If you were to find a small underweight or distressed hedgehog during the hibernation period then contact your nearest wildlife rescue centre.Once Hedgehogs do settle down for hibernation they will lower their breathing and heartbeat down and enter a state of 'Torpor'.
Bats enter into hibernation in November, we probably won't see them until May. Whilst in the state of 'Torpor' they slow their heart rate to 4 beats a minute, they use less energy and survive on fat from the foods they consumed before hibernation.
Not all bats roost in caves, most will seek out a gnarly old tree and find a nice nook within it that's warm, comfortable and will protect them from the elements. If a bat can't find a suitable roost they will find a way into roof spaces, old barns and abandond buildings usually in groups and cuddle together. Caves also provide good conditions for bats, as long as they have a constant temperature and are free from rain and winter frosts.
A great way to help bats is to install a bat box, though bat boxes don't replace the conditions of a cave or roof, it would be a welcome shelter for winter. Bat boxes arent very big and as long as they are placed in a sheltered spot that gets some sun during the day they may get some little visitors.
The Dormouse certainly lives up to its name, it comes from the French word dormir 'to sleep', the old English name for the Dormouse is 'the sleeper', it's the only British rodent that hibernates. Dormice go into hibernation from mid-October and re emerge around April or May. As with other hibernating animals they will eat as much as possible just before hibernation to build up a good fat store. It's body temperature, breathing and heart rate will drop, this saves energy and allows them to survive the winter, using only the body fat built up. Dormice usually make deep nests in a hedgerow or on the ground, the nest is lined with grass, wool & leaves.
Although Honeybees & Bumblebees are very closely related, their winter behaviours are very different.
A colony of Honeybees will live throughout the entire winter, actively keeping the nest warm and safe. Although the winter colony is much smaller than that in summer, it will still contain thousands of bees. The bees eat and work all winter long, such activity requires a large store of food. In the very cold weather they will huddle together with the aim of keeping the Queen snug. Some beekeepers provide their hives with feeders of sugar syrup to keep them going through the cold months, especially if they have taken honey that year.
Bumblebees do not maintain colonies during the winter. The last brood of the summer colony will contain a number of 'New Queens'. They mate and find a safe nesting place in which to spend the winter. This is usually a small hole in the ground or another protected spot just big enough for her. Only the 'New Queen' Bumblebees hibernate until spring. The rest of the colony dies. While the Bumblebee Queen hibernates she doesn't eat or work. Her depressed rate of metabolism allows her to live for long periods while burning very little fuel.
- Frogs, Toads and Newts
This is a very contentious issue. Some say Frogs usually hibernate at the bottom of a pond, they take in oxygen through their skin so it's important to make sure pond plants get enough sunlight to photosynthesise. Some Toads hibernate, usually in mud, log piles and even under leaf litter, some carry on as normal and don't hibernate at all. Newts don't really hibernate they will spend the winter at the bottom of a pond, under a log pile or compost/garden waste heap. Somewhere that is sheltered from the winter frosts. If there is a mild spell over winter they will still adventure out and forage. To help amphibians you can always make a hibernaculam.
- Grass Snakes, Adders & Slow worms
Adders and Grass Snakes hibernate through the coldest part of the year and emerge in spring time, they sleep in sheltered dry spots away from elements, this may be in tree roots, fallen tree, an abandoned animal burrow or a compost heap.
Slow worms will burrow more underground or find a sheltered spot in tree roots.
Some of the larger UK butterflies hibernate in various forms as eggs, caterpillars, chrysalis, or as fully fledged adults.Those hibernating do so in the coldest winter months because there are no food sources available. Those hibernating do so in the coldest winter months because there are no food sources available.Brimstone, Small Tortoiseshell, Redadmiral and Peacocks will all hibernate, potentially in your butterfly hotel, in dried-out grass stalks, in brickwork, or in your house.
Don’t disturb a hibernating butterfly, they do not harm, and releasing one that’s woken in the central heating means death if it’s cold outside. Instead, put it in a shoebox with a thin cut on one side. Then place it in a cold, dark place like your garage or shed to finish hibernating. For further information on how we can all help our butterflies and moths take a look at diygarden.co.uk/wildlife/ultimate-guide-to-butterflies
Ladybirds as with most other hibernating insects will eat as much as possible before hibernation. They start to look for somewhere to hibernate in early winter, you may start seeing the odd lady bird in your house, shed, garage or under leaf litter. They hibernate in huge numbers, if they were to wake up during hibernation they with starve to death as there will be nothing for them to eat. You can also help lady birds by putting a ladybird/inesct home in the garden placed in amongst the flower bed and sheltered during the winter months.
Hibernation allows the chance of survival during cold periods when food is limited, body temprature and heart rate lowers allowing their bodies to go into a state of Torpor. Though animals eat and drink less and use their fat reserves during hibernation they may still need to get up, have a stretch and visit the bathroom. Some hibernators may even have a food store incase they need a nibble.
For those that don't hibernate or migrate during winter such as birds need a little extra help from us, put out bird food, some left overs such as fruit and fresh water. For more information visit www.rspb.org.uk
Image Anne Coatesy | Adobe Stock