The bears at our sanctuary hibernate for different lengths of time. Some bears disappear for up to four to six months und rarely show themselves during that time. They withdraw into their dens that we sometimes can’t even see from the other side of the fence. Other bears still show up from time to time and look for food. In the wild, bears hibernate for around two to six months, too.

The bear houses and wooden cabins the bears can use to hibernate besides their own dens, aren’t heated. We spread straw and saw dust layers on the ground so that the bears don’t lay on the concrete floor. The dens our bears dig themselves, don’t get extra cushion from us. If needed, the bears cushion it on their own. They use leaves or moss for it. The dens are just big enough for them to turn around inside. That way, the body temperature can’t escape that quickly and helps to keep the den warm. Inside of the den remain plus degrees, while outside the temperature can drop below zero.

The bears usually sleep alone in their den. They dig their dens they use to hibernate by themselves and withdraw alone to sleep during winter. But we do have some exceptions at our sanctuary. Michal and Tapsi hibernate together in a den. Moreover, we have the siblings Sylvia and Pavle who mostly share one straw bed in winter and the bear brothers Ben and Felix hibernate together, too.

The bears don’t get as much food in winter as they get in summer or in fall. That’s when they build up fat reserves for the colder period. During winter, there is no active feeding. We only give food, when the bears need it and observe the bears’ behavior. If we notice that they are looking for food, we give them some. But if we don’t see the bears in their enclosures anymore and there’s still food laying around, we know the bears withdrew in their dens and don’t need food anymore.

How long the bears hibernate can differ from year to year. It depends among other things on how strong and cold the winter is. Mostly it’s Clara who is the first bear going into hibernation. We’d say that Clara also hibernates the longest, because she usually starts hibernating at the end of October and only shows up again at the beginning of March. Whereas the other bears go into hibernation around January and already wake up again mid of March.

Our bears hibernate at different places. Around 50 % of them dig their own dens, the others use the artificial dens or boxes in the bear houses. For example Ida hibernates in concrete tubes on a straw bed. Sometimes the bears use self-dug dens from the past years, that are still undamaged. Or they dig new dens for the winter. It can happen that when a bear finished digging his den, another bear steals it for his hibernation. The bear then has to start all over again.

During that time, the metabolism slows down, the bears are very lazy. Heart and breath rate slow down, too. You can compare it with when people are in a deep-sleep phase. In case of danger, they can wake up anytime. Some bears completely disappear for about three months and don’t drink or eat anything. Others sometimes leave their dens when it’s good weather and look for food. But they don’t eat a lot, at the most about three kilos. Then they go back to sleep.

Whether the rescued bears from Germany were able to hibernate before, is hard to say. At our sanctuary, all of them hibernate in winter. The rescued bears from Eastern Europe never had the chance to withdraw in winter, before they got to our sanctuary. Luna from Albania, who was rescued in 2017, never hibernated before. During her first winter here, she started digging her very first den right away and used it for hibernation. Michal from Poland also hibernates every year. He shares his den with Tapsi.