American Black Bear

Scientific name: Ursus americanus

American Black Bear - Ursus americanus
American Black Bear - Ursus americanus. Photo © James Hager / Getty Images.

The American black bear (Ursus americanus) is a large carnivore that inhabits the forests, swamps, tundra throughout the more northerly reaches of North America. In some areas such as the Pacific Northwest, it commonly lives at the edges of towns and suburbs where it has been known to break into storage buildings or cars in search of food.

Black bears are one of three bear species that live in North America, the other two being the brown bear and the polar bear.

Of these bear species, black bears are the smallest and most timid. When encountered by humans, black bears often flee rather than attack.

Black bears have powerful limbs and are equipped with short claws that enable them to break apart logs, climb trees, and collect grubs and worms. They also claw apart beehives and feed on the honey and bee larvae they contain.

In the colder parts of their range, black bears seek refuge in their den for the winter where they enter a winter sleep. Their dormancy is not true hibernation, but during their winter sleep the refrain from eating, drinking or excreting waste for as long as seven months. During this time, their metabolism slows and heart rate falls.

Black bears vary quite considerably in color throughout their range. In the east, bears are usually black with a brown snout. But in the west, their color is more variable and can be black, brown, cinnamon or even a light buff color.

Along the coast of British Columbia and Alaska, there are two color morphs of black bears that are distinct enough to earn them nicknames: the whitish "Kermode bear" or "spirit bear" and the blue-gray "glacier bear".

Although some black bears may be colored like brown bears, they two species can be distinguished by the fact that the smaller black bears lack the dorsal hump characteristic of the larger brown bears.

Black bears also have larger ears that stand more erect than those of brown bears.

The ancestors of today's American black bears and Asiatic black bears diverged from the ancestor of today's sun bears some 4.5 million years ago. Possible ancestors of the black bear include the extinct Ursus abstrusus and Ursus vitabilis known from fossils found in North America.

Black bears are omnivores. Their diet includes grasses, berries, nuts, fruit, seeds, insects, small vertebrates and carrion.

Black bears are adaptable to a range of habitats but tend more towards forested areas. Their range includes Alaska, Canada, the United States and Mexico.

Black bears reproduce sexually. They reach reproductive maturity at 3 years of age. Their breeding season occurs in spring but the embryo does not implant in the mother's womb until late fall. Two or three cubs are born in January or February. The cubs are very small and spend the next several months nursing in the safety of the den. Cubs emerge from the den with their mother in spring. They remain under the care of their mother until they are about 1½ years old at which time they disperse to seek out their own territory.

Size and Weight

About 4¼-6¼ feet long and 120-660 pounds

Classification

American black bears are classified within the following taxonomic hierarchy:

Animals > Chordates > Vertebrates > Tetrapods > Amniotes > Mammals > Carnivores > Bears > American black bears

The closest living relatives of black bears are Asian black bears. Surprisingly, the brown bear and the polar bear are not as closely related to black bears as Asian black ears are despite the present geographic proximity of their ranges.