7-year-old mother Black Bear with cubs in a den under a fallen tree. (Photo courtesy of the North American Black Bear Center)

Bear Hibernation


Posted on Thursday March 8, 2018

On some of these cold, dark winter days, I bet that many of you have thought about how great it would be to just hunker down and hibernate to get through it all. To lay down for a nap in November and wake up to a warm sunny day in April; wouldn’t that be nice?

It probably wouldn’t be long before you start to get hungry, thirsty, cold, and even have to go to the bathroom. For you and me, sleeping straight through winter would be much easier said than done, but for a bear, it’s no problem!

How do they do it?

Studies of hibernating bears using advanced sensors have revealed some interesting insights into how bears survive the winter in a state of hibernation.

First, the bears are safely able to drop their body temperature by about 60 C. Dropping their body temperature by approximately 13 per cent allows them to substantially slow their metabolic rate and oxygen consumption by around 75 per cent. It’s still not known how this is accomplished, but bears are much more efficient than other hibernating mammals who must lower their body temperatures much more to achieve a similar decrease in metabolism.

Bears are basically just sleeping through hibernation, and still require energy to maintain blood flow and bodily functions.

They are somehow able to get all their energy from their fat stores, and not use up any muscle or bone mass that humans would use up under the same circumstances.

To conserve energy, they take only one to two breaths per minute and keep their heart beats to about four per minute. They also don’t go to the bathroom during the entire hibernation period and recycle nutrients from what would normally be excreted in waste products.

Scientists are still unsure exactly how bears and other hibernators are able to do what they do, but they continue to search for answers. The secrets to bear hibernation might one day assist in treating trauma patients, easing the complications of extended bedrest, or even allow humans to easily endure long-term space travel.