Black Bear
Black bear, Ursus americanus
Black bears are the smallest and most common bear species in North America, and by far the most commonly found bear in North American late Pleistocene deposits. They are extremely adaptable and occupy a diverse range of climates and habitats. Although these bears continued to occupy much of North America, including the midwest, well into recent times, increasing human populations over the past several centuries, and increasingly negative bear-human interactions, have drastically reduced the availability of acceptable habitats. Currently they are found in the less settled, forested regions of the U.S., particularly in the mountainous regions of the western states and the Appalachian states, as well as through most of Canada and even into northern Mexico. These relatively unagressive bears are omnivorous with a heavy reliance on plant foods.
American Black Bear. By Alan D. Wilson (Nature's Pics online) [CC-BY-SA-3.0 (www.creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons.
Length: 1.2-1.9 m (4-6.2 ft)
Shoulder Height: 0.7-1.0 m (2.3-3.3 ft)
Weight: males 60-225 kg (130-500 lb); females 40-150 kg (90-330 lb)
Macdonald 2006
Physical Description:
Black bears are the smallest of the three North American bear species. They have a broad skull with a narrow muzzle and large jaw, small eyes, and small, rounded, upright ears that are set well back on the head. They have short, curved claws on all four feet, and they are highly dextrous. These bears are covered in soft fur, with a short dense underfur and long, coarse guard hairs. The fur is of uniform color, with the occasional white blaze on the chest. Despite their name, black bears come in a range of colors, including black, brown, cinnamon, blonde, blue-gray, blue-black and, in rare cases, white (non-albino). The black bear, particularly those with brown or cinnamon colored fur, is distinguishable from the grizzly bear by the lack of a shoulder hump and its straight, rather than dished, facial profile. Interestingly, the average black bear was much larger during the Pleistocene than in present times, and its size has noticeably decreased over the course of the Holocene. In fact, early recoveries of late Pleistocene black bear remains were misidentified as grizzly bears (Ursus arctos), given the much larger size than is currently exhibited by this animal (Kurtén and Anderson, 1980).
Black bears are incredibly adaptable and utilize habitats ranging from dense forests to open woodlands and brushlands. They prefer habitats with difficult terrain (e.g., mountainous and/or swampy locations), thick understory vegetation that provides some protective cover, and abundant food sources in the form of fruit and/or nut-bearing shrubs and trees.
Black bears are omnivorous, with a diet that consists primarily of plant materials. Although they will eat a variety of smaller or young mammals and fish, they are not active predators and typically consume vertebrates in the form of carrion or as opportunistic prey (Pelton 2003). Indeed, most of their animal protein comes from consuming insects. The black bear's diet varies regionally and seasonally, although typically they will consume grasses, forbs, buds, leaves and young shoots from trees and shrubs in spring, and berries, fruits, and nuts in summer and fall. Bears that live near human communities will also incorporate human-related foods into their diets, such grain crops (e.g., corn), orchard fruits, pet foods and garbage.
Black bears commonly mark trees within their home range by biting or clawing the tree trunk at about 1.5-2.0 m above the ground (Pelton 2003). Although the function of these marks is unknown, it has been noted that the frequency of tree markings peaks during mating season. Black bears are typically solitary animals except for mother-cub groups, breeding pairs and groups gathering in areas of aggregated food sources. As with many bears, the black bear enters a period of winter dormancy, which is characterized by retreat into a winter den site for long period of relative inactivity. Although black bears do not eat, drink, defecate or urinate during this period, they can be roused easily and will react to a disturbance, unlike true hibernators (Pelton 2003). Black bears commonly den in caves, where available, although they will also construct crude nests within briar thickets or dense shrubs, or within high cavities of large trees. Denning behavior is inferred for late Pleistocene black bears as well, given the large number of remains that have been recovered from cave sites from this period.
During the late Pleistocene, black bears were widely distributed across North America. In fact, they are the most commonly found bear in North American late Pleistocene deposits.
Not only did black bears survive the late Pleistocene extinctions, but these animals continued to occupy much of their current range up to historical time periods. As human occupations expanded throughout North America, black bears have gravitated towards more sparsely populated areas, although they continue to enjoy a widespread distribution.
Black bear remains have been recovered from late Pleistocene sites throughout the Midwest; however, they are most plentiful in Missouri cave sites.
- The American black bear is about twice as common as all other bears combined! (Macdonald 2006)
Kurtén, B. and E. Anderson. 1980. Pleistocene Mammals of North America. Columbia University Press, New York.
Macdonald, D. W. (editor). 2006. The Princeton Encyclopedia of Mammals. Princeton University Press, Princeton, NJ.
Pelton, M. R. 2003. Black Bear. In, Wild Mammals of North America, edited by Feldhamer, G. A., and B. C. Thompson, 547-555. The Johns Hopkins University Press, Baltimore, MD.
Related Animals:
