Latin Name: Ursus arctos

Family Name: Ursidae (Bear)

Related Species:

• Brown bears and "grizzly" bears are actually the same species. Some people are confused because North Americans commonly call this species the grizzly bear in interior areas and the brown bear in coastal areas although they are the same species. Coastal bears are typically larger and darker, due to salmon and other rich coastal foods in their diet. The interior-dwelling grizzly got its name because of its grizzled, silvertipped coat. This species ranges in color from very light blond to almost black.
• Black bears (Ursus americanus) are a forest-dwelling species that, in part of its range, overlaps with grizzly bears. Typically they are smaller, with shorter front claws and without such a marked shoulder "hump." Black bears may be black, brown, cinnamon, or even pure white (the white form is sometimes seen in a coastal portion of British Columbia).

Estimated Population: There are about 1,200 grizzlies in the lower 48 states, roughly 31,7000 in Alaska, and approximately 25,000 in Canada.

Endangered Status: South of Canada, the grizzly bear has been listed as threatened on the U.S. Endangered Species list since 1975. The protection of this listing has resulted in increasing populations in the Yellowstone area and in the Northern Continental Divide Ecosystem (Glacier Park and adjacent areas). Elsewhere south of Canada this species is highly endangered.

Appearance: : Grizzlies range from very dark brown to very light blond. Frequently they are light brown or tan with darker colored legs. Dark-colored bears are most abundant coastal areas while the lighter colored ones are most abundant in interior areas. They often have white-tipped hairs, giving grizzled appearance. Hump above shoulders. Facial profile concave. Claws of front feet can reach nearly four inches long and are used for digging.

Size: In coastal areas males can average amost 800 pounds and in interior areas males may average about 320 pounds. Females are smaller and average 60-70 percent of male weights in the same area. The largest individuals on the coast may weigh as much as 1,400 pounds. Bears are largest in the fall just before hibernation. Over the course of winter they may loose a third or more of their body weight.

Life Span: A grizzly bear older than 25 is a very old bear. Bears living as old as 30 have been documented.

Some information provided courtesy of eNature.com®.

The Beary Complicated Bear Family Tree

Note: Graphical representation of the bear family tree located at the bottom of this page.

There are only eight species of bear living in the world today but tracing their family tree is not as easy as one might imagine. Scientists trace the bear's complex lineage using fossil evidence and DNA analysis. From this information we know that all eight species have a common ancestor, Ursavus, that lived more than 20 million years ago. Fossil evidence suggests that Ursavus was a small animal about the size of a fox or raccoon. Ursavus lived in the forest, had a thick fur coat to keep it warm in cold winters, and was omnivorous, eating both meat and plant matter.

The Ursavus family line split into two subfamilies of what are considered ancestral bear-dogs: the Ailuropodinae (which ultimately evolved into the giant panda (Ailuropoda melanoleuca) that lives in China today) and the Agriotherium (which ultimately evolved into the Ursidae lineage).

About 15 million years ago, Ursidae diverged into two new lineages: the Tremarctinae, known as short-faced bears; and the Ursinae, known as true bears.

Short-faced bears were likely the first bear group to wander across the Bering Land Bridge into what is now North America. Those that did not migrate into North America became extinct. The short-faced bears that moved in North America also became extinct, but not before one species moved into South America. The spectacled bear (Tremarctos ornatus), so named for the cream colored bands that encircle its eyes, is found in small sections along the Andes Mountains. The giant panda and the spectacled bear are the only living representatives of much older lineages of the bear family.

Ursinae gave rise to the six other bear species that exist in the world today. About 3.5 million years ago, early Ursine bears began migrating to North America by way of the Bering Land Bridge. These bears evolved into the American black bear (Ursus americanus). Ursine bears that remained in the Old World radiated into southern Asia and likely evolved as they became isolated from each other. The sun bear (Helarctos malayanus) probably became isolated on the Malay Peninsula; the sloth bear (Melursus ursinus) on the Indian subcontinent; and the Asiatic black bear (Selenarctos thibetanus) on the Tibetan plateau.

The brown or grizzly bear (Ursus arctos) began to evolve 1.6 million years ago. Brown bears were once found throughout Europe and Asia and eventually wandered into North America, following the same route taken by ancestors of the black bear. Scientists believe that the brown bear lineage split over 300,000 years ago to form the polar bear (Ursus maritimus), theorizing that a group of early brown bears became isolated in colder regions and ultimately adapted to life on ice.

Meet the bears of the world. (This is a 168K PDF file.)

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