grizzly bear or grizzly, large, powerful North American brown bear, characterized by gray-streaked, or grizzled, fur. Grizzlies are 6 to 8 ft (180–250 cm) long, stand 31/2 to 4 ft (105–120 cm) at the humped shoulder, and weigh up to 800 lb (360 kg). Primarily omnivorous, they are excellent hunters and prey on large mammals such as deer; they relish ants and other insects and depend on plants, roots, and berries to supplement their diet. Once widespread in the western half of North America, from the Arctic Circle to central Mexico, habitat destruction and hunters nearly exterminated the grizzly. Classified as threatened under the U.S. Endangered Species Act, small groups can be found in protected regions of Alaska, W Canada, and the U.S. Rocky Mts. The grizzly is a subspecies, Ursus arctos horribilis, of the brown bear, U. arctos, which has small populations throughout North America and N Eurasia; it can crossbreed in the wild and captivity with the polar bear. It is classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Carnivora, family Ursidae.