Grizzly+Bear+Background+Research

**__Grizzly Bear Background Research__**
__Scientific Name:__ Ursus arctos horribilis

__Size: __ 6–7 feet long; 3–3 ½ feet high at shoulders; 300–1,720 pounds

__Range:__ Western United States; Canada; Southern Alaska

__Habitat: __ Diverse, including tundra, grasslands, and forests

__Conservation Status: __ Threatened

__Fun Facts: __ -Grizzly bears have excellent senses of smell and hearing but poor eyesight -Unlike most hibernating animals, grizzlies are light sleepers, and wake easily when disturbed. -Adult males may lose up to one-third of their body weight during hibernation. -These big bears can run up to 35 miles per hour! -A grizzly’s large muscular hump on its shoulders and long front claws make the bear an excellent digger.

__Lifestyle: __ Grizzlies are generally loners, but they are still North America’s most social bear. They gather at food sources and often forage in family groups. Large adult males will aggressively defend their place at the head of their social circle, but grizzlies are not territorial and their home ranges often overlap. Home territories vary in size depending on location, but in Yellowstone National Park, they average 50 square miles. Bears usually hibernate from late fall to spring, but those in warmer regions may stay active through the winter. Each year they may return to the same den, which is usually within a sheltered slope, under a large rock, or within the roots of a large tree. Grizzlies can be unpredictable when startled—especially if they feel that cubs or food are threatened. __Food: __ The polar bear primarily eats ringed or bearded seals. The bears rely on their exceptional sense of smell to guide their hunts. They will stalk the seals on the pack ice or lie in wait near the seals’ air holes until the prey surfaces from the water. Polar bears are also scavengers and eat some seabirds and vegetation.

__Food:__ For such big animals, grizzlies usually chow on the small stuff: berries, grasses, roots, bulbs, tubers, and insects. They also eat small mammals and carrion. Bears in the Canadian Rockies are known to hunt larger prey, such as mountain goats, elk, moose, and even black bears. Grizzlies in northwestern America gather at salmon streams during the summer to catch fish migrating upstream to spawn.

__Life Cycle: __ Female grizzlies usually give birth to two cubs during hibernation in January or February. The newborns are blind, hairless, and tiny—weighing less than a pound. They stay in their dens until springtime, when they have reached about 20 pounds. Once they are out in the world, they remain with their mother for at least two years more. Their average lifespan in the wild is 25 years, but grizzly bears have lived as long as 50 years in captivity.

__Population Status and Threats:__ Grizzly bears are currently found in only 2 percent of their historic range within the U.S. In the early 1800s, an estimated 100,000 grizzlies lived in the western United States (excluding Alaska), but their numbers declined greatly as settlers moved west. Logging, mining, and road construction further reduced grizzly numbers by destroying their habitat. Today, there are about 1,000 of these bears in Montana, northern Idaho, northeastern Washington, and Wyoming. In Alaska, the grizzly bear population is estimated at 30,000.

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