Animals Are Awesome

These days, much of the scientific community considers bears to be not only true hibernators, but super hibernators!

Unlike other, smaller mammals who must wake often to eat and pass waste, and to keep their temperature from falling too low, grizzly bears are able to hibernate without waking for an entire season if need be.

During hibernation a bear is able to live entirely off its fat, despite an average hibernating BMR of 8000 kcal a day. The bear is able to break down the urea that accumulates as a byproduct of fat metabolism, and the resulting nitrogen is used to build protein. This allows a bear to maintain organ and muscle mass under circumstances that would normally lead to severe muscle atrophy. Overall, a bear will lose 15-30% of its weight during hibernation.

Ursus arctos horribilis, better known as the grizzly bear, is distinguished by its humped shoulders, long claws and concave facial profile with heavy brow (think Winnie the Pooh).

Bears did not used to be considered true hibernators, because other deep hibernating mammals typically go through a drastic decrease in body temperature, whereas a bear’s core temperature remains above 88ºF during hibernation (normal for a bear being ~100ºF). Whereas smaller mammals may experience core drops to as low as 40ºF. This enables the bear to more quickly awaken and react to threat. Easy to see why stumbling into a bear cave even in the dead of winter can have a dangerous outcome.