Hibernation is a special deep sleep. Some animals hibernate during the winter so they don't have to go out in the cold and look for food. When an animal hibernates its body temperature drops and heartbeat and breathing slow down. This helps them save some energy.

Reindeer don't hibernate as they are well adapted for the cold habitat in the Artic. Their coat is made up of lots of hollow hairs which help trap heat close to the body. They also makes them more buoyant. This means they can float in water easier.

Did you know reindeer used to live in England and Ireland years ago during the Ice Age?

The Reindeer