It appears that I – and my handy-dandy mammalogy textbook – were wrong on the bears-not-hibernating front. According to a fabulous bear resource I found today: www.bear.org (appropriately enough), bears DO hibernate. I know, go figure. Here’s an excerpt from their hibernating fact sheet (they say it far more eloquently than I could):
When people defined hibernation simply in terms of temperature reduction, bears were not considered hibernators. However, when biologists discovered the many metabolic changes that let black and grizzly bears hibernate up to 7 ½ months without eating, drinking, urinating, or defecating, they realized that body temperature was only a small part of hibernation.
They redefined mammalian hibernation as a specialized, seasonal reduction in metabolism concurrent with scarce food and cold weather (Watts et al. 1981).
Black bears are now considered highly efficient hibernators.
Hibernators the size of chipmunks hibernate differently. They lower body temperature to near freezing but wake up every few days to raise body temperature to near normal, eat stored food, and eliminate body wastes. Then they lower body temperature and repeat the cycle.
The confusion about what to call black bear hibernation is a matter of definition. Further confusion has arisen because it differs with region and fatness (see other exhibits).
People have called black and grizzly bear hibernation torpor, winter sleep, dormancy, and carnivorean lethargy. The leading physiologists now simply call it hibernation.
Ok. Despite the fact that my circa 2000 textbook of Mammalogy stated that bears do not hibernate (which is what I was taught in both of my mammalogy classes in grad school), bear biologists DO classify them as hibernators. My bad.
I came across the bear.org site because of a news article I heard on NPR this morning about the increase of bear populations in many states, which has lead to a review of hunting policies regarding black bears in some places. It seems that some states are surveying residents to weigh popular opinion about bears, with the idea of potentially relaxing hunting regulations.
I’m of two minds about this. My initial reaction was to be sad and frustrated that instead of finding ways to better educate the public about bear safety, states and municipalities are just turning to the same old methods – killing them.
But in thinking about it further, I thought about the deer population here in the northeast, and how large in is in many states. Human hunting isn’t enough to control this species. And I’ve got to imagine that even with regulations lifted, bear hunting wouldn’t become as popular as deer hunting. It’s the idea of hunting with dogs that I find distressing – that has the potential for unnecessary cruelty to the hunted animal. But I know many hunters here in New England, and none of them hunt bears with dogs, so how prevalent is that in other parts of the country?
Another factor is the realistic fact that living around bears can be scary – no matter how much you know about them. Population control is certainly not a bad thing – I just don’t want to see it taken to the extreme.
How do you feel about the idea of having bears in your backyard or neighborhood? How aggressively would you want your state or county to regulate their populations?
