U.S. Fish & Wildlife Service Grizzly Bear (Ursus arctos horribilis)

A symbol of America’s wildlands, is green vegetation, wild fruits and the grizzly or brown bear is one berries, nuts, and bulbs or roots of the largest North American of certain plants. Grizzlies also eat land mammals. The grizzly bear’s a great deal of insects, sometimes historic range covered much of tearing rotten logs apart and turning North America from the mid-plains over heavy stones in search of the westward to California and from adult insects or their larvae. central Mexico north throughout Alaska and Canada. Today, the grizzly Most of the meat in the grizzly’s bear is found in only about 2 percent diet comes from animal carcasses, of its original range in the lower 48 or carrion, of big game animals, states. although it will sometimes prey on elk or moose calves or smaller mammals. Grizzly bears need a very large home For grizzlies along the west coast of range (50 to 300 square miles for Canada and in Alaska, salmon is an females; 200 to 500 square miles for important food source. males), encompassing diverse forests interspersed with moist meadows The grizzly bear must eat enough and grasslands in or near mountains. to store huge amounts of fat needed In the spring, bears usually range to sustain it through its long winter at lower elevations and go to higher sleep. The grizzly’s ability to eat altitudes for winter hibernation. large quantities of rich food and store fat without suffering from heart Larger than the black bear, male disease or cholesterol problems is of grizzly bears stand about 7 feet great interest to medical scientists. If USFWS tall and weigh from 300 to 600 scientists can determine how grizzlies pounds (and occasionally more accomplish this, that information may than 800). Females are smaller, be useful in preventing human heart During the next 5 to 6 months, the usually weighing between 200 and disease. grizzly will not consume water or 400 pounds. Although a standing nourishment but will use up its grizzly is commonly perceived to be a At the top of the food chain, adult accumulated fat. threatening pose, bears stand when grizzly bears have little to fear from they are simply curious or surveying other wild animals. Grizzly cubs may Male grizzly bears usually emerge their surroundings. Otherwise they fall prey to mountain lions, wolves, from the den in March or April, while generally remain on all fours. and other bears if they stray too far females emerge in late April and May. from their mother. When a grizzly comes out of its den, Unlike the black bear, the grizzly the first food is sometimes carrion bear has a rather concave face, Early in the fall, grizzly bears begin from animals that did not survive the high-humped shoulders, and long, looking for a proper place to dig winter. A grizzly will usually travel to curved claws. The grizzly’s thick their dens, and may travel many lower elevations to reach vegetated fur, which varies from light brown to miles before finding a suitable area. areas. nearly black, sometimes looks frosty- Generally, they seek a high, remote looking, hence the name “grizzly,” mountain slope where deep snow Mating season is from June through or the less common “silvertip.” The will serve as insulation until spring. July. Grizzly bear embryos do not grizzly has shorter, rounder ears than Grizzlies often dig beneath the roots begin to develop until the mother the black bear. of a large tree to create their dens. begins her winter hibernation, Obstructing roots are chewed up, although mating may have taken Except for mating and caring for and loose rocks and earth are thrust place up to 6 months before. As with the young, grizzly bears primarily through the narrow entrance by other bears, if the mother has not lead solitary lives, spending most of the powerful strokes of the grizzly’s accumulated enough fat to sustain their time foraging, or looking for forepaws. herself as well as developing cubs, the food. The grizzly is North America’s embryos may not implant (develop). largest omnivore, meaning it eats The grizzly bear will generally enter In January, usually 1 to 3 cubs, each both plants and other animals. About its den in October or November. weighing only a pound or less, are 80 to 90 percent of the grizzly’s food born. The cubs gain weight quickly become food conditioned because and often have reached 10 to 20 of the availability of human-related pounds by the time they come out of “attractants,” which include garbage, the den. pet foods, livestock carcasses, and improper camping practices. Food- Cubs remain dependent upon their conditioned bears seek out human mother’s milk for almost a year, stay use areas for these foods and can with their mother for up to 3 years, become dangerous. Bears can also and reach breeding maturity at about become habituated to people when 4 1/2 to 5 1/2 years. In some cases they lose their normal avoidance they may not breed until 8 1/2 years response. An example of habituated of age. When they do reach breeding bears are road-side bears feeding on age, females usually only breed every natural foods that do not flee when 3 years. Males compete with each vehicles stop. This can eventually other for breeding opportunities and lead to conflicts between people and seek females each year. Grizzlies bears and to grizzly bear mortality -- usually live to 15 to 20 years of age, not only in human-populated areas of and a few survive for up to 30+ the grizzly’s range but if attractants years. are not stored properly also at back country recreation sites. Between 1800 and 1975, grizzly bear populations in the lower 48 states Today, in the lower 48 states, grizzlies decreased from estimates of more can be found in Wyoming, Montana, than 50,000 to less than 1,000. The Idaho, and Washington. The six grizzly was eliminated from much ecosystems in the conterminous U.S. of the West by the late 1800s. As identified by biologists as containing mountainous areas were settled, suitable habitat for grizzly bears are: development contributed to an Yellowstone (northwestern Wyoming, USFWS increase in human-caused mortality. southwestern Montana, and eastern Livestock depredation control, Idaho), Northern Continental recovery in this ecosystem. Much habitat deterioration, commercial Divide (northwestern Montana), work is needed to help the bears trapping, unregulated hunting, the Cabinet-Yaak (northwestern in the transboundary Selkirks, and the perception that grizzlies Montana), Selkirks (northern Cabinet-Yaak and North Cascades threatened human life were leading Idaho and eastern Washington), the ecosystems. The Bitterroot causes of the animal’s decline. North Cascades (Washington), and ecosystem also requires much effort Bitterroot (central Idaho and western to reach recovery. In 1975, the U.S. Fish and Wildlife Montana). Service listed the grizzly bear as These successes have been largely a threatened species under the There are more than 500 grizzlies due to a cooperative effort among Endangered Species Act, meaning living in the greater Yellowstone area. several organizations called the it is considered likely to become In addition, there are more than Interagency Grizzly Bear Committee. endangered (“endangered” means 500 grizzlies living in the Northern Established in 1983, the committee a species is considered in danger of Continental Divide Ecosystem, about includes the USDA-Forest Service, extinction within all or a significant 30 to 40 in the Selkirk Mountains National Park Service, U.S. portion of its range). Many of the in northern Idaho and northeast Geological Survey, U.S. Fish and current threats to the survival of Washington, another 30 to 40 in the Wildlife Service, Bureau of Land grizzly bears are associated with Cabinet-Yaak ecosystem in northern Management, State agencies in degradation of habitat due to rural Idaho and western Montana, and less Montana, Wyoming, Idaho, and or recreational development, road than 20 in the North Cascades. There Washington, and the Provinces building, and energy and mineral are no known grizzly bears in the of British Columbia and Alberta. exploration. Habitat destruction in Bitterroot Ecosystem at this time. The committee coordinates habitat valley bottoms and riparian areas In Alaska, where grizzlies are called management, research, and education is particularly harmful to grizzlies brown bears, they are estimated to and outreach for the grizzly bear. because they use these linkage number more than 30,000. There are habitats to travel from one area to more than 25,000 grizzly bears in another when they are searching for Canada. food. Some private landowners and companies are trying to help grizzlies The grizzly bear recovery effort by voluntarily protecting grizzly has met with some successes thus linkage habitats. far. Grizzlies in the Yellowstone U. S. Fish and Wildlife Service ecosystem are now delisted. We Endangered Species Program The biggest threat to the grizzly know less about the grizzlies in 4401 N. Fairfax Drive, Room 420 is human-caused mortality. Some the Northern Continental Divide Arlington, VA 22203 grizzly bears are accidentally killed ecosystem, but a project finishing 703-358-2390 by hunters who mistake them for in 2007 will give us a better idea of http://www.fws.gov/endangered/ black bears, which are legal game. population size in this ecosystem. More commonly, grizzlies may We still have more to do to reach March 2007