Hibernation and winter rest
During its hibernation, the hedgehog will eat nothing at all. But before going into hibernation, it will build a reserve by eating extra insects, worms and beetles. During hibernation, the body temperature will lower. This slows its metabolism down to a minimum.
The length of the hibernation depends on the environmental temperature. When temperatures rise in March already, the animal will wake up. This poses no problem if the temperature does not drop down again. But when two periods of frost are separated by one warm week, the hedgehog is in trouble. When it awakes, it is hard for the animal to get back to sleep. And a hedgehog that is awake but unable to find food will not survive in the cold.
Other animals, such as the Eurasian badger, do not hibernate. However, they do rest and remain in their setts. There they also keep their food reserve.
There are also several insects that take it easy during the winter. Some butterflies, such as the peacock butterfly and the lemon butterfly, do not spend the winter as a pupa but as a butterfly. They look for a secluded frost-free place, for example in a crack or a hollow tree. When the temperature drop below 15 degrees Celsius, it becomes too cold to move fort these cold-blooded animals. Therefore they will just remain where they are.
They queen of wasps also looks for a secluded place to survive, while the rest of the colony dies. In springtime, the queen will lay eggs to found a new colony of wasps.