It's that time of year when the natural world slows down. As the nights draw in and the temperature drops, animals of all sizes do what they can to save resources to survive. Be they herbivores or predators, there's less food all around, so the best way to conserve vital energy is to stay warm and go to sleep or hibernate.
The most likely hibernator you will come across is your friendly local hedgehog but there are also two other British mammals which hibernate. Both of these are 'Champion Species' of The Mendip Hills National Landscape, the hazel dormouse and bats (specifically the greater horseshoe bat). Many species slow down and enter a state of torpor but don't truly hibernate. All will use late autumn as a time of plenty to fatten and see them through the winter. The bats will be flying around trying to find the last flying insects, dormice will be feasting on autumn fruit and nuts, and the hedgehogs will clear your garden of slugs and snails.
After spending most of the year in the canopy of hazel and other trees, the hazel dormouse makes its way to the base of coppice stools, where they will make nests in the leaf litter to see out the winter. The greater horseshoe bats' preferred hibernacula are in the many limestone caves of the Mendip Hills. Mendip is one of Britain's last strongholds for these amazing but endangered animals.
With a wingspan of up to forty centimetres and living over thirty years, successful hibernation is very important. Males hibernate either on their own or in very small groups, but the females will hibernate in large colonies of between fifty and two hundred individuals. As the bats mate in the late summer and give birth in June, many of the females will be hibernating while pregnant.
During hibernation, the bat's body temperature lowers drastically. Their pulse drops from around one thousand beats per minute whilst flying to under 25 hibernating, meaning they expend far less energy and require much less food.
Of course, mammals aren't the only animals to hibernate. Adders and all cold-blooded animals also do so. The adder's favourite place is in the foundations of Mendip's many drystone walls. Like caves, these are dry and have a relatively constant temperature, and luckily for the adder, many of their prey species also like to spend the winter there, providing an easy snack when everyone wakes up in the spring.
Remember, just because you can't see wildlife through the winter, it's still there, just being efficient and waiting for the world to spring back to life in the new year.
