A symbol of America's wildlands, the grizzly or brown bear is one of the largest North American land mammals. The grizzly bear's historic range covered much of North America from the mid-plains westward to California and from central Mexico north throughout Alaska and Canada. Today, the grizzly bear is found only in about 2 percent of its original range in the lower 48 states.

Grizzly bears need a very large home range (50 to 300 square mile for females; 200 to 500 for males), encompassing diverse forests interspersed with moist meadows and grasslands in or near mountains. In the spring, bears usually range at lower elevations and go to higher altitudes for winter hibernation.

Larger than the black bear, male grizzly bears stand about 7 feet tall and weigh from 300 to 600 pounds (and occasionally more than 800). Females are smaller, usually weighing between 200 and 400 pounds. Although a standing grizzly is commonly perceived to be a threatening pose, bears stand when they are simply curious or surveying their surroundings. Otherwise they generally remain on all fours.

Unlike the black bear, the grizzly bear has a rather concave face, high-humped shoulders, and long, curved claws. The grizzly's thick fur, which varies from light brown to nearly black, sometimes looks frosty, hence the name "grizzly," or the less common "silvertip." The grizzly has shorter, rounded ears than the black bear.

Except for mating and caring for the young, grizzly bears primarily lead solitary lives, spending most of their time foraging, or looking for food. The grizzly is North America's largest omnivore, meaning it eats both plants and other animals. About 80 to 90 percent of the grizzly's food is green vegetation, wild fruits and berries, nuts, and bulbs or roots of certain plants. Grizzlies also eat a great deal of insects, sometimes tearing rotten logs apart and turning over heavy stones in search of the insects themselves or their larvae.

Most of the meat in the grizzly's diet comes from animal carcasses, or carrion, of big game animals, although it will sometimes prey on elk or moose calves or smaller mammals. For grizzlies along the west coast of Canada and Alaska, salmon is an important food source. The grizzly bear must eat enough to store huge amounts of fat needed to sustain it through its long winter sleep. The grizzly's ability to eat large quantities of rich food and store fat without suffering from heart disease or cholesterol problems is of great interest to medical scientists. If scientists can determine how grizzlies accomplish this, that information may be useful in preventing human heart disease.

At the top at the food chain, adult grizzly bears have little to fear from other wild animals. Grizzly cubs may fall prey to mountain lions, wolves, or other bears if they stray too far from their mother.

Early in the fall, grizzly bears begin looking for a proper place to dig their dens, and may travel many miles before finding a suitable area. Generally, they seek a high, remote mountain slope where deep snow will lie until spring to serve as insulation. Grizzlies often dig beneath the roots of a large tree to create their dens. Obstructing roots are chewed up, and loose rocks and earth are thrust away by strokes of the grizzly's forepaws.

The grizzly bear will generally enter its den in October or November. During the next 5 to 6 months, the grizzly will get no water or nourishment of any kind, but will use up its accumulated fat. Male grizzly bears usually emerge from the den in March or April, while females emerge in late April or May. When a grizzly comes out of its den, its first food is sometimes carrion from animals that did not survive the winter. A grizzly will usually travel to lower elevations to reach vegetated areas.

Mating season is from June through July. Grizzly bear embryos do not begin to develop until the mother begins her winter hibernation, although mating may have taken place up to 6 months before. As with other bears, if the mother has not accumulated enough fat to sustain herself as well as developing cubs, the embryos may not implant (develop).

In January, usually one to three cubs, each weighing only a pound or less, are born. The cubs gain weight quickly and often have reached 20 pounds by the time they come out of the den. As many as half of all cubs may not reach breeding age---a leading reason for the grizzly's low numbers. Cubs remain dependent upon their mother's milk for almost a year, stay with their mother for 2 to 3 years, and reach breeding maturity at about 4 1/2 to 5 1/2 years. In some cases they may not breed until 8 1/2 years of age. When they do reach breeding age, females breed only every 3 or more years. Males compete with each other for breeding opportunity and seek females each year. Grizzlies usually live to be 15 to 20 years of age, and a few survive for up to 30 years.

Between 1800 and 1975, grizzly bear populations in the lower 48 states decreased from estimates of more than 50,000 to less than 1,000. The grizzly was eliminated from much of the West by the late 1800s. As mountainous areas were settled, development contributed to an increase in human-caused mortality. Livestock depredation control, habitat deterioration, commercial trapping, unregulated hunting, and the perception that grizzlies threatened the human life were leading causes of the animal's decline.

In 1975, the U.S. Fish and Wildlife Service listed the grizzly bear as a threatened species under the Endangered Species Act, meaning it is considered likely to become endangered ("endangered") means a species is considered in danger of extinction within all or a significant portion of its range). Many of the current threats to the survival of grizzly bears are associated with the degradation of habitat due to rural or recreational energy and mineral exploration. Habitat destruction in valley bottoms and riparian areas is particularly harmful to grizzlies because they use these "corridors" to travel from one area to another when they are searching for food. Some private landowners and companies are trying to help grizzlies by voluntarily protecting grizzly corridors.

Some grizzly bears are accidentally killed by hunters who mistake them for black bears, which are legal game. But the biggest threat to the grizzly is human-caused mortality. Grizzlies become habituated to humans because of what biologists call "attractants," which include garbage, petfoods, livestock carcasses, and improper camping practices. This can eventually lead to conflicts between people and bears--not only in populated areas of the grizzly's range but also in backcountry recreation sites.

Today, in the lower 48 states, grizzlies can be found in Wyoming, Montana, Idaho, and Washington. There are at least 350 grizzlies living in the northwestern Montana Rockies, about 250 in or around Yellowstone National Park, about 25 in Selkirk Mountains in northern Idaho and northeast Washington, another 20 or so in the Cabinet-Yaak ecosystem in northern Idaho and western Montana, and 5 to 20 in the North Cascades. In Alaska, where they are called brown bears, they are estimated to number more than 30,000. There are about 22,000 grizzly bears in Canada.

One goal of the Fish and Wildlife Service's plan to restore the grizzly bear in the lower 48 states is to recover grizzly populations in all ecosystems that are known to have suitable habitat. The ecosystems in the conterminous U.S. that have been identified by biologists as suitable for grizzly bears are: Yellowstone (northern Wyoming, southwestern Montana, and eastern Idaho), Northern Continental Divide and Cabinet-Yaak (northwestern Montana), Bitterroot (central Idaho and western Montana), Selkirks (Idaho and eastern Washington), and the North Cascades (Washington).

The grizzly bear recovery effort has been met with some success thus far. Grizzlies in the Yellowstone ecosystem have now reached the recovery target. Grizzlies in the North Continental Divide ecosystem have nearly reached recovery goals, and are expected to reach them within a year or two. These successes have been largely due to a cooperative effort among several organizations called the Interagency Grizzly Bear Committee. Established in 1983, the committee includes the U.S.Forest Service; National Park Service; Bureau of Land Management; state agencies in Montana, Wyoming, Idaho, and Washington; Canadian wildlife management agencies; and Native American tribes. The committee coordinates habitat management, research, and education and outreach for the grizzly bear.