Nest building
Adult hedgehogs usually begin constructing their winter nest in late autumn, when temperatures start to drop and food becomes scarce. They collect leaves, grass, twigs, and other plant materials to create a cozy, insulated nest that will protect them from the cold.
The nest is usually built in a sheltered location, such as under a bush or in a hollow log. Hedgehogs will often reuse the same nest year after year.
Storing food
Hedgehogs are omnivorous and their diet includes a variety of foods, such as insects, worms, snails, fruits, and seeds. In order to survive the winter without food, hedgehogs need to fatten up by eating as much food as they can before the cold weather sets in.
They store the fat in their body, which will provide them with energy during their winter sleep.
Hibernation
Hedgehogs usually enter hibernation in late autumn or early winter. The exact timing depends on the weather conditions and the hedgehog's weight. Hedgehogs that are too light may not be able to survive the winter and will not enter hibernation.
When a hedgehog enters hibernation, its body temperature drops, its heart rate slows down, and it stops breathing for long periods of time. It will sleep for most of the winter, only waking up occasionally to eat or drink.
Hedgehogs can lose up to one-third of their body weight during hibernation, so it is important for them to have enough fat reserves before the cold weather sets in.