Two Native Americans paddle their canoe across a lake, just offshore, on a foggy morning. A black bear sow is none too pleased and has sent her cub up a nearby birch tree for safety.
The American black bear, Ursus americanus, is the smallest of the three bears species found in North America, and are found only in North America. Although they all live in North America, black bears are not closely related to brown bears and polar bears; genetic studies reveal that they split from a common ancestor 5.05 million years ago. Black bears can be distinguished from brown bears by their smaller size, their more concave profiles, their shorter claws and the lack of a shoulder hump.
Black bear fur is usually a uniform color except for a brown muzzle and light “crescent moon” markings that sometimes appear on their chests. Despite their name, black bears show a great deal of color variation. Individual coat colors can range from white, blond, cinnamon, or light brown to dark chocolate brown or to jet black, with many intermediate variations existing. Bluish tinged black bears occur along a portion of coastal Alaska and British Columbia. White to cream colored black bears occur in coastal islands and the adjacent mainland of south-western British Columbia. Albino specimens have also been recorded. Black coats tend to predominate in moist areas such as New England, New York, Tennessee, Michigan and western Washington. 70% of all black bears are black, though only 50% of black bears in the Rocky Mountains are black. Black bears with white-bluish fur are known as Kermode (glacier) bears and these unique color phases are only found in coastal British Columbia, Canada.
Black bears are omnivorous: plants, fruits, nuts, insects, honey, salmon, small mammals and carrion. In northern regions, they eat spawning salmon. Black bears will also occasionally kill young deer or moose calves.
The American black bear is distributed throughout North America, from Canada to Mexico and in at least 40 states in the U.S. They historically occupied nearly all of the forested regions of North America, but in the U.S. they are now restricted to the forested areas less densely occupied by humans. In Canada, black bears still inhabit most of their historic range except for the intensively farmed areas of the central plains. In Mexico, black bears were thought to have inhabited the mountainous regions of the northern states but are now limited to a few remnant populations.
Black bears are extremely adaptable and show a great variation in habitat types, though they are primarily found in forested areas with thick ground vegetation and an abundance of fruits, nuts, and vegetation. In the northern areas, they can be found in the tundra, and they will sometimes forage in fields or meadows.
Black bears tend to be territorial and non-gregarious in nature. They mark their territories by rubbing their bodies against trees and clawing at the bark. They are strong swimmers, doing so for pleasure and to feed. Black bears climb regularly to feed, escape enemies or to hibernate. Their arboreal abilities tend to decline with age. Adult black bears are mostly nocturnal, but juveniles are often active in daytime. The bears usually forage alone, but will tolerate each other and forage in groups if there is an abundance of food in one area.
Most black bears hibernate depending on local weather conditions and availability of food during the winter months. In regions where there is a consistent food supply and warmer weather throughout the winter, bears may not hibernate at all or do so for a very brief time. Females give birth and usually remain denned throughout the winter, but males and females without young may leave their dens from time to time during winter months.
Black bears were once not considered true or "deep" hibernators, but because of discoveries about the metabolic changes that allow black bears to remain dormant for months without eating, drinking, urinating, or defecating, most biologists have redefined mammalian hibernation as "specialized, seasonal reduction in metabolism concurrent with scarce food and cold weather". Black bears are now considered highly efficient hibernators.
Black bears enter their dens in October and November. Prior to that time, they can put on up to 30 pounds of body fat to get them through the seven months during which they fast. Hibernation in black bears typically lasts 3–5 months. During this time, their heart rate drops from 40–50 beats per minute to 8 beats per minute. They spend their time in hollowed-out dens in tree cavities, under logs or rocks, in banks, caves, or culverts, and in shallow depressions. Females, however, have been shown to be pickier in their choice of dens, in comparison to males. A special hormone, leptin is released into their systems, to suppress appetite. Because they do not urinate or defecate during dormancy, the nitrogen waste from the bear's body is biochemically recycled back into their proteins. This also serves the purpose of preventing muscle loss, as the process uses the waste products to build muscle during the long periods of inactivity. In comparison to true hibernators, their body temperature does not drop significantly (staying around 35 degrees Celsius) and they remain somewhat alert and active. If the winter is mild enough, they may wake up and forage for food. Females also give birth in February and nurture their cubs until the snow melts. During winter, black bears consume 25–40% of their body weight. The footpads peel off while they sleep, making room for new tissue. After emerging from their winter dens in spring, they wander their territories for two weeks so that their metabolism accustoms itself to the activity. They will seek carrion from winter-killed animals and new shoots of many plant species, especially wetland plants.In mountainous areas, they seek southerly slopes at lower elevations for forage and move to northerly and easterly slopes at higher elevations as summer progresses.
Up to 85% of the black bear's diet consists of vegetation, though they tend to dig less than brown bears, eating far fewer roots, bulbs, corms and tubers than the latter species. Young shoots from trees and shrubs during the spring period are important to black bears emerging from hibernation, as they assist in rebuilding muscle and strengthening the skeleton and are often the only digestible foods available at that time. Berries, fruits, grasses, nuts and buds are often eaten. During this period, they may also raid the nut caches of squirrels. Black bears are fond of honey, and will gnaw through trees if hives are too deeply set into the trunks for them to reach them with their paws. Once the hive is breached, black bears will scrape the honeycombs together with their paws and eat them, regardless of stings from the bees.
The majority of the black bear's animal diet consists of insects such as bees, yellow-jackets, ants and their larvae. Black bears will fish for salmon during the night, as their black fur is easily spotted by salmon in the daytime. However, the white furred black bears of the islands of western Canada have a 30% greater success rate in catching salmon than their black furred counterparts.They will also prey on mule and white-tailed deer fawns in certain areas. In addition they have been recorded preying on elk calves in Idaho and moose calves in Alaska. Black bear predation on adult deer is rare but has been recorded. They may hunt adult moose by ambushing them as they pass by. Black bears often drag their prey to cover, preferring to feed in seclusion and frequently begin feeding on the udder of lactating females, but generally prefer meat from the viscera. The skin of large prey is stripped back and turned inside out with the skeleton usually left largely intact. Unlike wolves and coyotes, black bears rarely scatter the remains of their kills. Vegetation around the carcass is usually matted down by black bears and their droppings are frequently found nearby. Black bears may attempt to cover remains of larger carcasses, though they do not do so with the same frequency as cougars and grizzly bears. They may climb up to bald eagle nests to eat the eggs or chicks. Black bears have been reported stealing deer and other animals from human hunters.
It is estimated that there are at least 600,000 black bears in North America. In the United States, there are estimated to be over 300,000 individuals. However, the Louisiana black bear (Ursus americanus luteolu) and Florida black bear (Ursus americanus floridanus) are threatened subspecies with small populations. The current range of black bears in the United States is constant throughout most of the northeast (down to Virginia and West Virginia), the northern midwest, the Rocky mountain region, the west coast and Alaska. However it becomes increasingly fragmented or absent in other regions. Despite this, black bears in those areas seems to have expanded their range during the last decade. Surveys taken from 35 states in the early 1990s indicate that black bears are either stable or increasing, excepting Idaho and New Mexico.
Black bears currently inhabit much of their original Canadian range, though they do not occur in the southern farmlands of Alberta, Saskatchewan, and Manitoba.
Mexico is the only country where the black bear is classed as endangered.
Black bears feature prominently in the stories of some of America's indigenous peoples. One tale tells of how the black bear was a creation of the Great Spirit, while the grizzly was created by the Evil Spirit. In the mythology of the Haida, Tlingit, Tsimshian people of the Northwest Coast, mankind first learned to respect bears when a girl married the son of black bear Chieftain. In Kwakiutl mythology, black and brown bears became enemies when Grizzly Bear Woman killed Black Bear Woman for being lazy. Black Bear Woman's children, in turn, killed Grizzly Bear Woman's own cubs. The Navajo believed that the Big Black Bear was chief among the bears of the four directions surrounding Sun's house, and would pray to it in order to be granted its protection during raids.
Unlike grizzly bears, which became a subject of fearsome legend among the European settlers of North America, black bears were rarely considered overly dangerous, even though they lived in areas where the pioneers had settled. Black bears rarely attack when confronted by humans, and usually limit themselves to making mock charges, emitting blowing noises and swatting the ground with their forepaws. However, according to Stephen Herrero in his Bear Attacks: Their Causes and Avoidance, 23 people were killed by black bears from 1900 to 1980. The number of black bear attacks on humans is higher than those of the brown bear, though this is largely because the black species outnumbers the brown rather than them being more aggressive.
For more information, to include conservation efforts, visit both The North American Bear Center
and The Great Bear Foundation