Black Bears and Hibernation
Featured Animal: January 2016
Bears and Hibernation
We've heard the phrase before, " Ah, I slept like a bear (in winter)!", meaning that
the well-refreshed person slept well all night. And most of us have heard about bears
needing to eat and store fat for the winter hibernation. But did you know that bears
are not truly hibernating? In fact, no large mammal actually hibernates. While we
commonly refer to a bear's winter repose as hibernation, it is actually a process
In contrast true hibernators, such as squirrels, reduce their body temperature to near freezing and greatly reduce their metabolism, to conserve energy when food is low. But they need to wake up once a week or so to eat some food and pass waste.
Important to most humans, is how a bear wakes from torpor. Because of the need to increase blood temperature and metabolism to normal body temperature, true hibernators awake slowly and are lethargic until fully awake. In contrast, bears can awake from torpor quite suddenly if danger is sensed. This behavior is also beneficial to females bears - bear cubs are usually born in winter. The cubs do not hibernate or go into torpor. While their mother is sleeping, they nurse and sleep too. However, the mother awakes every now and again to care for her cubs and ensure they are safe and warm. This would not be possible if she were truly hibernating.
Because of their unusual torpor behavior - higher body temps, but no "awakening" (return to normal body temps) - recently scientists have begun calling them "super-hibernators", although this new term is not universally accepted. (nps.gov)
I wouldn't mind sleeping like a bear, as long as it were a male bear.
In the inter mountain west, denning begin in October (for females) and November (for males) and lasts until April (for males) and May (for females). When the bears wake up, they are HUNGRY. This is a time when there are many bear encounters within the suburban-wildland interface, because bears will venture into suburban landscapes to find food. Utah Division of Wildlife Resources’ Wild Aware program provides these tips for safety in bear country:
Maintain a bear-safe campsite
- Store food, drinks and scented items securely (in your vehicle, a bear-safe container or a tree — never in your tent)
- Dispose of trash in bear-proof dumpsters, if available
- Wipe down picnic tables
- Burn food off stoves or grills
- Pitch tents away from trails in the backcountry
- Always sleep inside your tent
- Never approach or feed a bear
- Report bear sightings to your campground host
Take precautions while hiking
- Stay alert at dawn and dusk, when bears are more active
- Go with a group, if possible
- Make noise as you travel through dense cover
- Stay away from animal carcasses
- Store food, trash and scented items (such as sunscreen) in airtight plastic bags
- Keep kids in the center of the group
Merritt, J. F. 2010. The biology of small mammals. Johns Hopkins University
Press, Baltimore, Maryland.
National Park Service. 2015. Denning and hibernation behavior. Accessed at: http://www.nps.gov/yell/learn/nature/denning.htm
Utah Division of Wildlife Resources. 2015. Safety in black bear country.
Utah Division of Wildlife Resources. 2011. Utah black bear management plan.