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The brown bear comes from a family of bears known as "Ursidae." A variety of races and species of this long feared bear are native to Eurasia and the northwestern regions of the United States. As many as 80 species of the brown bear are considered extinct.

Taxonomists previously have listed grizzly bears and brown bears as separate species. Technically, they are one in the same, though distinct subspecies do exist.

Brown bears found in the United States are commonly referred to as Grizzly Bears, whereas brown bears that make their home outside the U.S. are often known as simple brown bears.

The North American Grizzly bear has been hunted for centuries; so much so that only a few subspecies still exist. The North American Grizzly bear makes his home almost entirely in Alaska now, and most other subspecies of the brown bear that roamed the central portions of the United States are non-existent.

Eurasian brown bears are 4-7 feet long and weigh 300-550 pounds. The much larger Siberian brown bear weighs nearly 800 pounds, and is similar in size and weight to the North American Grizzly bear, also known as the common U.S. brown bear. This large, menacing animal has a prominent shoulder hump, small ears, and long, straight claws. Brown bears range in color from dark brown through light blonde.

Because of their tremendous size, brown bears rarely climb anything, even as cubs. Surprisingly agile, however, brown bears can run as fast as 30 m.p.h.

Grizzly bears carry a certain reputation for being dangerous, menacing animals. While it is true that brown bears have attacked humans for no apparent reason, most officials say cause for alarm is not necessary. They advise keeping a distance of 100 feet between the bear and you, and avoiding female bears with cubs altogether.

North American grizzly bears (common brown bear) are omnivorous animals, grazing on game, fish, berries and grass. They often store food shallow holes. Brown bears can also be found digging through the ground in search of rodents. Brown bears are methodical feeders who form deep, rutted trails after covering the same ground repeatedly in search of prey.

Brown bears have an amazing sense of smell which, under the right conditions, allows them to detect odors and prey more than a mile away. Bears use their strength and length to stand upright to test wind and smells.

Brown bear mating takes place from May through July, with the peak of activity occurring in early June. Brown bears do not have strong mating ties and individual bears are rarely seen with a mate for more than 7 days. Males often mate with more than one female during breeding season.

Hairless cubs, weighing less than one pound, are born 7 months after conception. Winter dens provide a home for the young. Litter size can range from 1-4 cubs, 2 being most common.

Offspring separate from their mothers around the age of two. After separation, the mother often breeds again immediately and produces a fresh litter of cubs the following year. When food is scarce, it is not uncommon for cubs to stay with their mothers until they are 5 years of age.

During the winter months when food is scarce, most brown bears enter dens and begin a period of hibernation that will last the entire season. While in this semi-sleep state, the bear's body temperature, heart rate and other metabolic rates are greatly reduced. The need for food and water is eliminated entirely. Pregnant female brown bears are the first to enter dens, and do so in early fall months. The female bear and newborn cubs are then subsequently the last to exit the den in the spring. Adult males have just the opposite behavior, entering dens last and leaving first.

Brown bears are protected species today, and those that once lived over western North American from Mexico to the northern most regions of the United States are extinct. National parks and zoos house a small number of Eurasian brown bears and as few as 9 or 10 populations of Alaskan brown bears still live in their native coastal area.

Alaska contains over 98 percent of the United States population of brown grizzly bears. Today, the Alaska Department of Fish and Game is responsible for managing Alaskan bears and their population. The grizzly bear is still a hunted animal in Alaska.

Brown bears in the wild have a lifespan of 22-26 years.