They once lived throughout most of North America, but hunting and agriculture drove them into heavily forested areas, where about 80,000 survive. Brown individuals, called cinnamon bears, often are born into the same litter as black cubs. They live on the shores and islands of Alaska. The European brown bear was once common throughout the continent but is now found only in mountainous areas of the USSR, Scandinavia, and southern Europe. The smaller Asiatic brown bears include the tan-colored Syrian bear and the snow bear of the Himalayas.
Grizzly bears are closely related to the Alaska brown bears.
Their name is derived from the whitish tips of their brown fur. Grizzlies once roamed from Mexico to Alaska but today are found only in a few national parks in the American West. Some authorities recognize the grizzly and the Alaska brown bear as two species distinct from U. arctos, which includes the brown bears of the Old World. The breeding season is in summer, after which each individual prepares for winter. This is especially important for the pregnant female, whose cubs will be born during the winter sleep.