The grizzly bear (Ursus arctos horribilis), native to the United States, has roots from around the world. The grizzly is the result of the evolution of a species that came into existence more than 1.3 million years ago. Feared and hunted to near extinction during expansion of the lower 48 United States, the grizzly has made a comeback in places like Montana, Washington and Wyoming.
Country of Origin
Grizzly bears as we know them originated in Asia around 1.3 million years ago, evolved from Etruscan bears that appeared in Europe about 5 million years before. Brown bears (Ursus arctos) crossed the Bering land bridge some 200,000 years ago. These bears eventually developed into the grizzly bear.
The Etruscan bear (Ursus etruscus) is the direct ancestor of the brown bear (Ursus arctos). The Etruscan bear ate meat and lived from about 5.3 million years ago to about 10,000 years ago. Fossils have been found in Asia, Europe and Africa. The Etruscan bear was much smaller than today's grizzly. Males were about 220 to 440 pounds and 50 to 77 inches long.
Ursus Arctos or Brown Bear
The most widely distributed bear in the world, Ursus arctos is the ancestor of the grizzly bear. The grizzly is, in fact, a subspecies of brown bear. Brown bear subspecies vary in weight greatly; some weigh as little as 300 pounds as adults, others 700, and others 1,200 pounds, the largest being the male Kodiak brown bear, which can weigh two tons. Grizzly bears average 300 to 400 pounds for females (sows) and 350 to 500 pound average for males (boars). Like grizzlies, brown bears have a characteristic hump on the shoulders that distinguish them from other bears.
Grizzly Bear Distribution
The grizzly bear's original range included Alaska, the western half of Canada, more than half of the western United States, and most of Mexico. The grizzly's range was severely reduced by unregulated hunting, trapping and habitat loss starting around the turn of the 20th century.
grizzly bear image by Melissa Schalke from Fotolia.com