Science Fair Project Encyclopedia
American Black Bear
The black bear occurs throughout much of North America from northern Canada and Alaska south into Mexico and from the Atlantic to the Pacific. This includes 39 of the 50 U.S. states and all Canadian provinces. Populations in east-central and the southern United States remain in the protected mountains and woodlands of parks and preserves. While there were probably once as many as two million black bears in North America, estimates in the 1980s put their numbers at less than 200,000. Some believe that the population has rebounded to some degree in recent years.
The black bear is approximately 5 feet (1.5 metres) long. Females typically weight about 90 pounds (40 kg), while males weigh about 290 pounds (130 kg). However, some can weigh up to 700 pounds (318 kg). Cubs usually weigh about 1 pound (500 g) at birth. It has small eyes, rounded ears, a long snout, a large body, and a short tail. The shaggy hair varies in color from white through chocolate brown, cinnamon brown, and blonde to black, but most black bears are indeed black or a darker shade of brown.
While black bears are capable of standing and walking on their hind legs, the usual posture is on all fours. The black bear's characteristic shuffle results from walking flat-footed, with the hind legs slightly longer than the front legs. Each paw has five strong, non-retractable claws used for tearing, digging, and climbing. One blow from a powerful front paw is enough to kill an adult deer. But in spite of their size and strength, black bears are surprisingly agile and careful in their movements.
Habitat and behavior
Black Bears prefer forested and shrubby areas but use wet meadows, high tidelands, ridgetops, burned areas, riparian areas, and avalanche chutes. They also frequent swampy hardwood and conifer forests. After emerging from their winter dens in spring, they seek southerly slopes at lower elevations for forage and move to northerly and easterly slopes at higher elevations as summer progresses. Black Bears use dense cover for hiding and thermal protection, as well as for bedding. They climb trees to escape danger and use forested areas as travel corriders. Black bears hibernate during winter and may build dens in tree cavities, under logs, rocks, in banks, caves, or culverts, and in shallow depressions.
Black bears reach breeding maturity at about 4 or 5 years of age, and breed every 2 to 3 years. Black bears breed in the spring, usually in May and June, but the embryos do not begin to develop until the mother dens in the fall to hibernate through the winter months. However, if food was scarce and the mother has not gained enough fat to sustain herself during hibernation as well as produce cubs, the embryos do not implant (develop).
Black bear cubs are generally born in January or February. The blind cubs weigh about 1/2 to 3/4 of a pound (250 to 350 g) [**** this contradicts previous statement that they weigh a pound ****] at birth, and twins are most common. By spring thaw, when the bears start leaving their dens, the cubs are fur-balls of energy, inquisitive and playful. They are weaned between July and September of their first year, and stay with the mother through the first full winter. They are usually independent by the second winter.
Cub survival is totally dependent on the skill of the mother in teaching her cubs what to eat, where and how to forage (find food), where to den, and when and where to seek shelter from heat or danger.
Black bears sometimes kill and eat small rodents and ungulate fawns .
Some common plant foods are listed below:
- oak (Quercus spp.) mast
- hazel (Corylus spp.) mast
- mountain ash (Sorbus spp.)
- tree cambium
- dogwood (Cornus spp.)
- kinnikinnick (Arctostaphylos spp.)
- cranberry (Vibernum spp.)
- huckleberry (Vaccinium spp.)
- blackberry (Rubus spp.)
- rose hips (Rosa spp.)
- gooseberry (Ribes spp.)
- sarsaparilla (Aralia nudicaulis)
- rhubarb (Polygonum alaskanum)
- lupine (Lupinus spp.)
- northern bedstraw (Galium boreale)
- lousewort (Pedicularis spp.)
- Labrador tea (Ledum groenlandicus)
- California coffeeberry (Rhamnus californicus)
- squawroot (Conopholis americana)
- dandelion (Taraxacum officinale)
- clover (Trifolium spp.)
- thistle (Cirsium spp.)
- black walnut ("Juglans nigra")
- buffaloberry (Shepherdia canadensis)
- lomatium (Lomatium spp.)
- cowparsnip (Heracleum lanatum)
- pine nuts.
- chestnuts ("castanea dentata")
- grapes ("vitis riparia")
Black bears also eat salmon (Oncorynchus spp.) and raid orchards, beehives, and crop fields. They pick from garbage dumps and trash bins of private homes. Black bears may occasionally prey on domestic sheep and pigs when their natural foods are scarce.
Black bears are as much an important game species as they are the center of controversy across the continent. Because their behavior has been little understood, Black bears have been feared and hated. They have also been portrayed as harmless play toys by film and television. Their low reproductive rate and late sexual maturation make them vulnerable to overharvest. Their active foraging habits and habitat encroachment by man have created man-bear conflicts.
Taxonomy and subspecies ranges
Currently accepted subspecies (with their respective ranges) include:
|Ursus americanus altifrontalis||the Pacific Northwest coast from central British Columbia through northern California and inland to the tip of northern Idaho and British Columbia|
|Ursus americanus amblyceps||Colorado, New Mexico, west Texas and the eastern half of Arizona into northern Mexico; southeastern Utah|
|Ursus americanus americanus||from eastern Montana to the Atlantic; from Alaska south and east through Canada to the Atlantic and south to Texas|
|Ursus americanus californiensis||the Central Valley of California, north through southern Oregon|
|Ursus americanus carlottae||Queen Charlotte Islands and Alaska|
|Ursus americanus cinnamomum||Idaho, western Montana, and Wyoming, eastern Washington and Oregon, northeastern Utah|
|Ursus americanus emmonsii||southeastern Alaska|
|Ursus americanus eremicus||northeastern Mexico|
|Ursus americanus floridanus||Florida, southern Georgia and Alabama|
|Ursus americanus hamiltoni||the island of Newfoundland|
|Ursus americanus kermodei||the central coast of British Columbia|
|Ursus americanus luteolus||eastern Texas, Louisiana, southern Mississippi|
|Ursus americanus machetes||north-central Mexico|
|Ursus americanus perniger||Kenai Peninsula, Alaska|
|Ursus americanus pugnax||Alexander Archipelago, Alaska|
|Ursus americanus vancouveri||Vancouver Island, British Columbia|
Current legal protections
Today, a major threat to the American black bear is widespread poaching, or illegal killing, to supply Asian markets with bear gall bladders and paws, considered to have medicinal value in China, Japan, and Korea. The demand for these parts also affects grizzly and polar bears. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (also known as CITES), a treaty among more than 120 nations, provides measures to curb illegal trade in wildlife and wildlife products across international boundaries, helping to protect the black bear from poaching.
While black bears are abundant in much of the West, some Eastern populations are at critically low levels. Two subspecies found in the southeastern U.S., the Louisiana black bear and the Florida black bear, still face decline mainly due to habitat loss and degradation.
In 1992, the U.S. Fish and Wildlife Service listed the Louisiana black bear as a threatened species under the Endangered Species Act, meaning it could become in danger of extinction throughout all or a significant portion of its range in the foreseeable future. The American black bear also is protected by the Act in the affected states (Louisiana, Mississippi, and Texas) due to its close resemblance to this subspecies. The Florida black bear is a candidate for protection under the Endangered Species Act.
- The Black Bear is the mascot of the University of Maine.
- Ursus americanus kermodei, commonly known as the "Spirit Bear", is a rare white (not albino) subspecies found in temperate rain forests on the Pacific northwest coast of North America. Native tradition credits these animals with supernatural powers.
- In August 2004, a wild black bear was found passed out drinking about 36 cans of stolen beer in Baker Lake, Washington , U.S. The bear opened a camper's cooler and used its claws and teeth to puncture the cans. It was found the bear selectively opened cans of Rainier Beer and left all Busch Beer unconsumed.
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