The grizzly bear (Ursus arctos ssp.), less commonly known as the silvertip bear, is a large subspecies of brown bear inhabiting North America.
Most adult female grizzlies weigh 290–400 lb, while adult males weigh on average 400–790 lb.
A grizzly bear’s front claws measure about 2-4 inches in length.
In North America, grizzly bears previously ranged from Alaska down to Mexico and as far east as the western shores of Hudson Bay; the species is now found in Alaska, south through much of western Canada, and into portions of the northwestern United States (including Idaho, Montana, Washington, and Wyoming), extending as far south as Yellowstone and Grand Teton National Parks.
Only about 1,500 grizzlies are left in the lower 48 states of the US. Of these, about 800 live in Montana. About 600 more live in Wyoming, in the Yellowstone-Teton area. There are an estimated 70–100 grizzly bears living in northern and eastern Idaho.
The grizzly bear is, by nature, a long-living animal. The average lifespan for a male is estimated at 22 years, with that of a female being slightly longer at 26. Females live longer than males due to their less dangerous life; avoiding the seasonal breeding fights in which males engage.
Grizzly bears hibernate for 5–7 months each year except where the climate is warm, as the California grizzly did not hibernate. During this time, female grizzly bears give birth to their offspring, who then consume milk from their mother and gain strength for the remainder of the hibernation period. To prepare for hibernation, grizzlies must prepare a den, and consume an immense amount of food as they do not eat during hibernation.