Ursus americanus
(Black Bear)

Order: Carnivora
Order Description: Carnivores
Family: Ursidae
Family Description: Bears

Black bears are smaller than grizzlies, they are dark in color from almost coal black to black with some brown and tan on their snout.The snout and forehead form a rather straight slope, rather than the convexClick word for definition forehead of a grizzly.They usually lack a hump across the shoulders and they have shorter front claws than a grizzly, about 1 ˝ inches long. They occur in different color phases. Here in the Rocky Mountains they can be brown in color, called “cinnamon” bears, and along the coast of northern British Columbia and southern Alaska there is a “blue” phase and a nearly white phase.  Males weigh 250 to over 500 pounds (112-225 kg), females are smaller weighing between 225 and 450 pounds (100-200 kg).  Some people confuse the brown phase or cinnamon bear with grizzlies.  Black bears are more common than grizzlies in Idaho.  Total length is 4.5 to 6.5 feet (137-188 cm), tail length is 3 to 7 inches (77-177 mm).

Throughout North America north of central Mexico; absent from southwestern United States.

Prefers mixed deciduous-coniferous forests with thick understory, but also occurs in various other situations.

Opportunistic omnivore; feeds on plant and animal food, including carrionClick word for definition and items from garbage dumps. Idaho study found individuals fed on forbsClick word for definition/grasses in spring, and mast in summer and fall.

Black bears are primarily nocturnalClick word for definition and crepuscularClick word for definition. During the day they rest in day beds usually in forest cover in slight depressions in the ground.  They hibernateClick word for definition for 5 to 7 months in their northern range, from about November until April.  Their hibernationClick word for definition is not as physiologically deep as some of the rodents, but they are in a deep sleep from which they only periodically arouse.  There is no excrement in their hibernation den indicating that they do not defecateClick word for definition while hibernating.  However, females do have their young while in hibernationClick word for definition. When inactive in hibernationClick word for definition, they occupy a den under a fallen tree, in a ground-level or above-ground tree cavity or hollow log, in an underground cave-like site, or even on the ground surface in dense cover. In an Idaho study, females used uncut timber for bedding, open timber and shrub fields for foraging and bedding, and riparianClick word for definition areas for feeding and travel corridorsClick word for definition. Their home range averages around 28 to 40 km2, but may reach several hundred km2 in some areas.  An Idaho study reported 13.5 km2 for males, and 2.7 km2 for females. Female and sub-adult home range is typically much smaller than that of adult males. In Idaho black bears move to higher or lower elevations in response to abundant food such as berries.  Population density estimates in different areas were 1 bear per 1.3 to 8.8 km2.  In Idaho recorded density was 1 bear per 1.3 km2.   Habitat quality affects breeding age and litter size. JA southern Appalachian study found enhanced productivity and survival of young when fall food supply, especially hard mastClick word for definition (nuts), was favorable. Idaho has a bear hunting season and adult males are most susceptible to hunting.  Historically they have been hunted for their meat and their fur.  Apparently, the guards at Britain’s Buckingham palace wear black hats made of black bear fur.  Black bears are dangerous.  Females with cubs and bears that have become acclimated to human garbage have been known to attack and even kill humans.

Black bears breed in June and July.  ImplantationClick word for definition of the fertilized egg is delayed about 4 months until about November. Young are born nearly naked, their eyes are closed, and they only weight about ˝ pound.  They nurse while the mother is hibernating, and by about 4 to 5 weeks their eyes open.  The cubs are only about 6 to 8 pounds when they emerge from hibernationClick word for definition with their mother.  Total GestationClick word for definition lasts 7 to 7˝ mo (average 220 days). Females give birth every 2 years at most; litter size varies from 1 to 5 (average 2). The young remain with the mother until the fall of their second year. Females first give birth at 2 to 5 years (usually 4-5 yr).  Males take no part in caring for the young, females aggressively defend their young by chasing off males.

Status: Game species
Global Rank: G5
State Rank: S5

Important State References:
Beecham, J.J. 1983. Population characteristics of black bears in west central Idaho. J. Wildl. Manage. 47:405-412.

Information written by Donald Streubel,© 2000
Map image provided by
Stephen Burton,© 2000
Design by Ean Harker©1999, 2000.