Winter is a special time for the brown bears at our sanctuaries and partner projects. When the golden fall days are over and the temperatures are getting lower, they get ready for hibernation. At our sanctuaries, we provide the bears with everything they need for the winter time: lots of space to dig dens, wooden cabins we built for them or bear houses in case they don't want or don't know how to dig a den for the winter and a individual care plan adapted to the needs for each bear.
What happens during hibernation?
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 longer with some food breaks. 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.
Read more about bear hibernation.
How long do brown bears hibernate?
The brown bears at our sanctuary hibernate for different lengths of time. Some bears disappear for up to four to six months and 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.
Do you feed the bears during hibernation?
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. At our sanctuaries, we only give food when the bears need it and observe the bears’ behaviour. 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.
Do all bears dig their own den?
Our brown bears hibernate in different places. Around half of the rescued bears in our sancturies dig their own dens, the others use the artificial dens or boxes in the bear houses. For example, bear Ida at BEAR SANCTUARY Müritz 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 finishes digging his den, another bear steals it for his hibernation. The bear then has to start all over again.
Is it cold in the dens? Are they heated?
The bear houses and wooden cabins the bears can use to hibernate besides their own dens, aren’t heated. At our sanctuaries, 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 burrows are just big enough for them to turn around in. This way, the body temperature cannot escape so quickly and helps to keep the cave temperate. Inside the den, it is therefore always warmer and drier than outside, mainly because of the wind shield. Especially healthy and well-fed bears are very little sensitive to cold temperatures.
Do the bears sleep alone in their dens?
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 sanctuaries where bonded individuals do hibernate together in a den.
Were the bears able to hibernate before you freed them from their cages?
Most of the brown bears that FOUR PAWS rescued from confined and poor conditions have never had the chance to withdraw in winter, before they got to our sanctuaries. They never had the possibility to hibernate either due to lack of a safe environment to do so or stress. At our sanctuaries and partner projects, almost all of the bears hibernate in winter. Some even have an extra long first sleep, but some bears take longer to mentally recover and thus it can take some years before they first hibernate.
Do the Asiatic black bears hibernate?
In general, Asiatic black bears do hibernate within the the northern latitudes (Russia, Korea, Japan and northeastern China) of their range. Further south, where food is available year round and hibernation is not necessary, females still build birthing dens and breeding usually takes place between June and July, with up to four cubs born during November to March.
At our BEAR SANCTUARY Ninh Binh in Vietnam, the rescued Asiatic black bears do not hibernate, they do however have some mildly reduced activity and may sleep a bit more than the rest of the year, but they don’t go into winter dormancy.
During the winter months, food quantities may be reduced depending on the bear and group. Some seasonal foods are changed and extra straw for bedding is provided.