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Bears

American Black Bear

The American black bear (Ursus americanus) occurs largely in forested habitat, but also in grassy meadows and tundra. It ranges across most of North America, from Alaska to Newfoundland, and south into Mexico. Although its populations are depleted in many parts of its range, it is still a widespread species. The black bear is usually black-colored, but may also be brown, light tan, or even white. Different colors may occur within a litter of cubs.

Black bears have larger ears than other bears. Size varies among populations; the overall range of adult weight is about 125-600 lb (57-272 kg). Males typically weigh about one-third more than females. The weight of individuals varies considerably during the year, depending on the amount of nourishing food available. Because they are much smaller than grizzlies, black bears try to stay out of sight when territories of the two species overlap.

Each black bear has a territory where it forages for berries, nuts, honey, insect grubs, fish, rodents, and carrion. A male's territory typically overlaps those of several sows. Black bears mate during the summer, with each female being visited several times by nearby males. The fertilized egg does not implant until the autumn. However, if the female bear is poorly nourished, the fertilized eggs do not implant at all. One to four cubs are born in January, after a gestation of 8-10 weeks.


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Science EncyclopediaScience & Philosophy: Ballistic galvanometer to Big–bang theoryBears - Grizzly And Other Brown Bears, Polar Bear, American Black Bear, Other Black-colored Bears