Grizzly Bear
Ursus arctos
This apex predator dominates its habitat. But over the last several centuries, its range has been decimated by hunting.
Habitat:
Grasslands, woodlands, forests, alpine meadows
Status:
Least concern
Weight:
290-790 pounds
Length:
6.5 feet
The grizzly's range throughout time.
Biology, Management, and Conservation. 2003. Johns Hopkins University Press, Baltimore. 2nd ed.
Grizzly bears are an apex predator, but routinely approach other, smaller, predators (usually timber wolves) to steal their kills. To avoid violence they rarely refuse to give up the carcass. Common large prey items for grizzlies include elk, bighorn sheep, caribou, whitetail and mule deer, bison, moose, and occasionally muskox (and have even been known to target black bears), and smaller ones include ground squirrels, voles, marmots, lemmings, bass, salmon, and trout. It also eats eggs, rodents, and insects. Grizzly bears living along the coast have also been known to scavenge dead whales, sea lions, and seals.
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Plant material also makes up a substantial portion of its diet, foraging pine nuts, grasses, tubers, berries, like blackberries, salmonberries, blueberries, buffalo berries, huckleberries, soapberries, and cranberries, and legumes.
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While they've been in America for a while, they did not migrate down from Alaska until 13,000 years ago. This is thought to be due to the presence of the utterly enormous short-faced bear, and grizzly's migration south into the rest of the U.S coincides with the extinction of the short-faced bear, likely at the hands of the Clovis people.
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The range map shown here is outdated, as it is mostly correct save for the fact that the grizzly bear's range stretched out farther east, to Quebec and Labrador, in Canada. The population, the Ungava grizzly (named after the Ungava Peninsula of Quebec), was formerly called U. arctos ungavaesis before its status as a distinct subspecies was demoted. The population's existence was largely considered apocryphal at best until 1975 when concrete evidence was presented of its existence. It went extinct sometime in the 20th century, and although it is not certain why, fur trapping is at least partially to blame.
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Grizzlies are typically solitary, save for mothers. However, grizzlies have an extremely low reproductive rate – one of the lowest of all land mammals in America. This is because they don't reach sexual maturity until the age of 5, and once females have mated, they delay their pregnancy until hibernation (as they give birth during torpor), and while delaying it can experience a miscarriage if they don't receive enough nutrition.
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Grizzly bears were at once feared and respected by native tribes. The California tribes refused to allow their young men to hunt alone due to the possibility of attacks by the California grizzlies, and they avoided areas with higher concentrations of bears. Some tribes led grizzly hunts with the same amount of preparation as warfare, and hunting groups had no less than several warriors.