As hedgehogs get ready to hibernate, their body temperature drops down to as low as 2°C, and after that they enter a period of deep sleep. They often use piles of dead leaves and vegetation in gardens as shelter, which means that they are particularly vulnerable when garden bonfires are lit.
Like all reptiles, grass snakes are cold-blooded and rely on basking in the sun to remain active. As the days get shorter, there is insufficient sun, so they crawl under piles of vegetation or into cracks in banks. They emerge in early summer and can be found basking in the sun once again.
Dormice can spend over half the year in hibernation. Indeed, their name might come from this trait, from the Latin word for sleep, dormire. They bed down in carefully constructed nests, woven from strands of honeysuckle bark and dried grass, for instance, well hidden in their woodland habitat.