Well, maybe we should have been born as bears. Bears are the most notorious animals for taking season-long snoozes every winter, but a surprising number of animals also have some interesting winter slumber styles, too.
Animals do this to survive the winter because the weather is cold and food is scarce. It is advantageous because these animals can quite literally shut themselves off for weeks at a time rather than try and survive through harsh weather conditions.
While many people think bears are hibernators, they actually participate in a similar, though not exact, practice. Instead of hibernating, bears fall into a deep sleep called torpor.
During torpor, heart rate and breathing rate decreases, body temperature reduces slightly and bears do not eat or release bodily waste. Bears can sleep more than days without eating, drinking, or passing waste! Instead, bears are able to literally turn their pee into protein through a urea recycling process.
Hibernation is a voluntary state an animal enters to conserve energy, when food is scarce, and minimize exposure to the winter elements. During hibernation an animal lowers its body temperature, slows its breathing rate, heart rate, and metabolic rate-the rate its body uses energy.
Hibernation can last days, weeks, or months depending upon the species. Chipmunks reduce their heart rate from the usual beats per minute to an almost undetectable 4 beats per minute during hibernation. Chipmunks do not sleep through the entire winter however, they wake every few days to feed on stored food and to urinate and defecate. Hibernation is triggered by decreasing day length and hormonal changes in an animal that dictate the need to conserve energy.
Before hibernating, animals generally store fat to help them survive the winter. Many, like the chipmunk, wake up for brief periods, but for the most part, true hibernators remain in this low-energy state through the winter. Waking takes time and uses up an animal's energy reserve.
Many animals once thought to hibernate, including bears, really only enter a lighter sleep-state called torpor. The winter behaviour of bears in captivity is often used as a yardstick to measure whether an enclosure is well suited to the species. Many animal parks practically compete in proving the quality of their enclosures on the basis of how much and how long the bears sleep. Although there is some justification for this approach, the lack of a winter resting phase is no sure indicator for inadequate keeping conditions.
There is no form of keeping bears in captivity that equals the natural, a wild life of a bear — to come close, an enclosure would have to cover around one hundred hectares per bear. Some bears tolerate a fenced habitat better than others. Many, due to deficits in their early development, have developed such strong behavioural defects that these dominate their lives almost completely. Freedom of choice is decisive: if wild animals have to live in captivity, it is important that they are provided with space for self-determination.
We assume no liability for this content. Winter dormancy or hibernation? The Bear: An artist of adaptation Pregnant polar bears dig a den in the snow in November.
They bury themselves there for the whole winter without hunting, and give birth to their young in the spring. During this time, their heart beat drops to an average eight beats per minute. This is not the case for bears. Another key difference is waking up from hibernation.
Most animals that hibernate, like squirrels, wake up gradually. However, bears can wake up instantly from their deep sleep. Due to these differences, some people argue that bears do not truly hibernate. Instead, they use distinct terms for what bears do such as winter sleep, carnivoran lethargy, torpor, and dormancy. Still, it is widely accepted by physiologists to label bears as hibernators.
Different species of bears hibernate for slightly different lengths of time, based mostly on their climate. Black bears can hibernate for up to seven and a half months without drinking water, eating food or defecating.
Grizzly bears typically hibernate between five to seven months. Mexican Black Bears usually do not hibernate at all or will hibernate for just a few weeks out of the year.
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