The American black bear (Ursus americanus) is confined primarily to forested regions of Alaska, Canada, the conterminous United States, and northern Mexico, although since the decline and extermination of the brown or grizzly bear (Ursus arctos) throughout much of its range, it has spread to several more open habitats, including the northern tundra and chaparral mountains of southern California. The grizzly bear is a competitor with, and sometimes a predator upon, the black bear.

Black bears commonly range in weight between 92-140 kg for females and 115-270 kg for males. Color phases are commonly black, chocolate brown, and cinnamon brown. A white phase occurs as well, and is most common on the Pacific coast of British Columbia.

Like other bears that hibernate, the black bear reaches it greatest body condition as cold weather approaches in late fall. During hibernation, body temperature drops from 38 degrees Celsius to 31-34 degrees, respiration slows, and the metabolic rate drops. Hibernation may begin as early as September and may last until May, and at times it is interrupted for outside excursions during periods of warm weather.

At least 75% of the black bear diet consists of vegetable matter, especially fruits, berries, nuts, acorns, grass, and roots. Insects, fish, rodents, carrion, and the occasional large mammal round out the diet. Home ranges have been found to vary from 235 ha on Long Island off southwestern Washington, to 20,000 ha in some tundra environments. Typical home range sizes in productive areas of Alberta, Washington, and Montana are about 520 ha for females, and 5,200 ha for males. Male territories often overlap and appear to be arranged to allow for maximum access to potentially estrous females. During times of plenty, black bears tend to remain within their home ranges and to vigorously chase off intruders, but as easily accessible food diminishes, bears will readily forage beyond their home ranges.

Breeding season peaks from June to mid-July, during which time the sexes briefly mix. Births take place in Jan. and Feb. during hibernation, with litter size usually two or three but ranging from one to five. Weaning usually occurs at 6-8 months, but young remain with their mother throughout their second winter.

Black bears have been intensively killed by people due to fear, predation on domestic animals and crops, for sport, and to obtain meat and fur. Attacks on livestock are generally believed to be negligible, but in some areas they pose a serious threat to cornfields and honey production. A more recent black bear threat has been their taking for medicinal use in the Orient, despite being listed in Appendix 2 by the Convention on International Trade in Endangered Species of Wild Fauna and Flora. Appendix 2 species are those that are not immediately endangered, but may become threatened unless their trade is subject to strict regulation. So far this hasn’t helped curtail illegal trading. In most states and provinces within its range, the black bear is legally hunted as a big game animal under wildlife agency regulations, with approximately 40,000 animals killed annually. The total North American black bear population estimates range from 500,000 to 700,000. The Uncompahgre Plateau contains a very healthy black bear population, and indeed is one of the most bear-dense regions of the lower 48.

Source: Nowak, R.M., ed. 1999. Walker’s Mammals of the World, Volume 1, Sixth

Edition. The Johns Hopkins University Press.