Hibernation is generally described as a long deep sleep, where animals will slow their metabolism and activity to sleep through the winter months and survive the cold weather. Overwintering or dormancy is a similar phrase, meaning that the animals will wake up for food during the milder times before spring, and we’ll explore that in this blog.
The hedgehog is the most known mammal in the UK to hibernate. As their food source is greatly reduced during the cold winter months, they will shelter in the depths of our gardens where they can enter dormancy until the Spring. Their numbers have greatly reduced in the UK, hugely due to disturbance through these months and being exposed to predators. It is important for hedgehogs to build up a large food reserve in late summer/early autumn, feeding on worms and other insects. Though they do sleep for most of the months, they may venture out for food and the toilet in milder weather or if woken.
Bats can be hard to see even in the summer unless you’re out during the evening when and overnight when they are most active. If you have ever visited our evening wildlife hide you may well have had bats pointed out to you by your guide as they begin their nights feeding as it gets to dusk. They will go into hibernation from around November until early spring, depending on the outside temperatures and need for food. They will eat small insects and can eat around 3.000 midges in one night, which is needed in the summer here in the Scottish Highlands. They need to store a lot of food to hibernate, conserving energy through the coldest spells. They choose to hibernate in rocks, trees or structures like sheds and houses and disturbing a roosting bat can put its life in danger.
Something people may not think about is what happens to our summer moths and butterflies in the winter. They become dormant, whether they are larvae, pupa or adults, depending on the species. It is not unusual to see them during the winter if the temperature increases. Some butterflies like the Painted Ladies will disappear completely in the winter and migrate to warmer climates. Some of our popular butterflies like the Peacock and Comma butterfly will hibernate as adults, often in sheds or house roofs.