Time to Hibernate In the winter, animals need to make changes to survive. Some adapt by growing a thicker coat of hair or fur to protect them from the cold, or—like the snowshoe hare—grow white fur in the winter to blend into the snowy landscape. Some move or migrate to a warmer area. Some animals hibernate, or sleep, in a safe place all winter. There are different kinds of hibernation. The true hibernators, such as woodchucks, sleep so deeply that they are almost impossible to wake up, though they do get up every few weeks to nibble on food. Others, like bears, are light sleepers and wake up periodically to forage for food.