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The American Black Bear (Ursus americanus) also known as the North American black bear is the most common bear species native to North America. It lives throughout much of the continent, from northern Alaskamarker south into Mexicomarker and from the Atlantic Oceanmarker to the Pacific Oceanmarker. This includes 41 of the 50 U.S. states, all Canadian provinces except Prince Edward Islandmarker, and portions of northern Mexico. In the mid 1990s, the population of black bears was estimated to have grown to between 396,000 and 476,000 in Canada, and between 339,000 and 465,000 in the United States, although some populations, such as the Louisiana black bear subspecies, remain threatened. Black bear populations in Mexico have been difficult to assess due to a lack of data.

Populations in the Southern United States remain in the protected mountains and woodlands of parks and preserves, though bears will occasionally wander outside the parks' boundaries and have set up new territories, in some cases on the margins of urban environments in recent years as their populations increase. Unlike its cousin, the Brown Bear, which is Eurasian in origin, the black bear evolved in North America two million years ago. It is thought by certain experts that the black bear's North American origin may account for its greater adaptability than the brown's, due to North America's greater prehistoric predation pressures. It is a close relative of the Asiatic Black Bear with which it is thought to share a common European ancestor which is thought to have diverged 3 million years ago, though genetic evidence is inconclusive. Both American and Asiatic species are considered sister taxa, and are more closely related to each other than other species of bear.

Taxonomy and evolution

The ancestors of the American Black Bear entered North America about 3.5 million years ago, through the Bering Land Bridge. At that time, unlike the Black Bears of today, they were nearly as large as Grizzly bears. During the ice-ages of the Late Pliestocene, the recently evolved Black Bears were able to out compete their competitors, largely due to their superior versatility, and ability to survive in many different habitats.

The American Black Bear is classified in the class Mammalia, order Carnivora and family Ursidae. Many subspecies are named, such as the Kermode bear, cinnamon bear, and glacier bear (or American blue bear). Currently accepted subspecies (with their respective ranges) include:





American Bear Sub-species
Sub-Species Name Native to

Ursus americanus altifrontalis Found in the Pacific Northwest coast from central British Columbiamarker through northern Californiamarker and inland to the tip of northern Idahomarker and British Columbia
Ursus americanus amblyceps Native to Coloradomarker, New Mexicomarker, west Texasmarker, the eastern half of Arizonamarker into northern Mexicomarker; southeastern Utahmarker
Ursus americanus americanus Found in eastern Montanamarker to the Atlantic coast; from Alaskamarker south and east through Canadamarker to the Atlantic and south to Texasmarker. Thought to be increasing in some regions.
Ursus americanus californiensis Found in the mountain ranges of Southern Californiamarker, north through the Central Valley to southern Oregonmarker
Ursus americanus carlottae Haida Gwaiimarker/Queen Charlotte Islandsmarker and Alaskamarker
Ursus americanus cinnamomum Idaho, western Montana, and Wyoming, eastern Washington and Oregon, northeastern Utah
Ursus americanus emmonsii southeastern Alaska. Stable.
Ursus americanus eremicus northeastern Mexico. Endangered.
Ursus americanus floridanus Floridamarker, southern Georgiamarker, and Alabamamarker. Threatened in Florida (state list).
Ursus americanus hamiltoni the island of Newfoundlandmarker
Ursus americanus kermodei the central coast of British Columbia
Ursus americanus luteolus eastern Texas, Louisianamarker, southern Mississippimarker. Threatened (federal list).
Ursus americanus machetes north-central Mexico
Ursus americanus perniger Kenai Peninsulamarker, Alaska
Ursus americanus pugnax Alexander Archipelagomarker, Alaska
Ursus americanus vancouveri Vancouver Islandmarker, British Columbia


Description

brown-colored American black bear
The American Black Bear usually ranges in length from and typically stands about at the shoulder./www.americanbear.org/Size.htm> Standing up on its hind feet, a Black Bear can be up to tall. Females are 33% smaller than males, an example of sexual dimorphism. Females weigh between ; males usually weigh between . Adult black bears can reach , but exceptionally large males have been recorded from the wild at up to long and at least 365 kilograms (800 lb). The biggest American Black Bear ever recorded was a male from North Carolina that weighed . At the other extreme, very small adult bears can weigh as little as in females and in males. Cubs usually weigh 200 to 450 g (7 to 16 oz) at birth. The adult has small eyes, rounded ears, a long snout, a large body, and a short tail. Though they generally have shaggy black hair, the coat can vary in color from white through chocolate-brown, cinnamon-brown, and blonde (found mostly west of the Mississippi River), to black in the east (the same is generally true in Canadamarker, the border being between Manitobamarker and Ontariomarker). They occasionally have a slight V-shaped white chest blaze. The tail is long.

Although Black Bears can stand and walk on their hind legs it is more normal for them to walk on all fours. When they do stand, it is usually to get a better scent or to look at something. Their characteristic shuffling gait results from their plantigrade (flat-footed) walk, with the hind legs slightly longer than the forelegs. Another reason for the apparent shuffle is that they commonly walk with a pacing gait. Unlike many quadrupeds, the legs on one side move together instead of alternating, much like a pacer horse. Each paw has five long, strong claws used for tearing, digging, and climbing. Though relatively less powerful than a grizzly bear, black bears are still enormously powerful. One paw swipe from a Black Bear is capable of killing an adult elk. In one account, a 55-kilogram bear cub lifted off a 140 to 146 kg rock "back-handed". When necessary, they can run at speeds up to 48 km/h (30 mi/h) and are good swimmers. The ears of a black bear are larger and more erect than those of the brown bear, and it lacks a prominent shoulder hump.

Ecology and behavior

Black bears are found in a wide variety of habitats across their range. They prefer forested and shrubby areas but they are also known to live on ridgetops, in tidelands, burned areas, riparian areas, agricultural fields, and, sometimes, avalanche chutes. Black bears can be found from hardwood and conifer swamps to the rather dry sage and pinyon-juniper habitats in the western states. They are active mostly durring the day, waking shortly before sunrise and bedding down a few hours after sunset.

Reproduction

Black Bear cub
Two Black Bears mating.
Females generally reach breeding maturity at 3 to 4 years of age and with adequate nutrition can breed every 2 years. In poor quality habitat, they may not mature until 5 to 7 and may skip breeding cycles. Males are sexually mature at the same age, but may not become large enough to win breeding rights until they are 4 to 5 years old (they have to be large enough to win fights with other males and be accepted by females). The sexes are independent, except for mid-June to mid-August (with some variation depending on latitude) for mating. However, due to embryonic diapause, the embryos do not begin to develop until the mother dens in the fall to hibernate through the winter months. Because of this delay, gestation can be 7 to 8 months, but actual development takes about 60 days. However, if food was scarce and the mother has not gained enough fat to sustain herself during hibernation as well as produce and feed cubs, the embryos will not develop.

The cubs are generally born in January or February. They are very small, about 283 to 397 grams (10 to 14 oz), and are blind, nearly hairless, and helpless when born. Two to three cubs are most common, though up to four and even five cubs have been documented. First-time mothers typically have only a single cub. The mother nurses the cubs with rich milk, and by spring thaw, when the cubs start leaving their dens. By this time, they are about 2 to 4 kilograms (4 to 8 lb). When the cubs sense danger, they climb high up a tree. They are weaned between July and September of their first year and stay with the mother through the first winter. The cubs become independent during their second summer (when they are 1.5 years old). At this time, the sow goes into estrus again.

Diet

Black bears are omnivores whose diet includes plants, meat, and insects. Their diet typically consists of about 10-15% animal matter, of which 3% is meat they actually killed. They are apex predators in North America, with the exception of areas where they coexist with the brown bear or grey wolf. The black bear eats a wide variety of foods, mainly fruits, nuts, seeds, berries, grasses, etc. In the state of Washington and other parts of the Pacific Northwest, black bears eat a large amount of skunk cabbage, horsetail and tree bark during the spring. They also commonly feed on spring acorns in Massachusetts.

bears feed on carrion, berries and insects (mainly for the larvae) such as carpenter ants, yellow jackets, bees, wasps and termites. They raid beehives for both honey and bee larvae as both are easy sources of carbohydrates (honey) and protein (larvae). They also kill and eat small mammals (such as rodents) and ungulates, mostly the young. In Michigan and the state of New York, black bears prey on white-tailed deer fawns. In addition they have been recorded preying on elk calves in Idaho and moose calves in Alaska. The taking of moose calves (their largest regular prey) can be hazardous, especially in contention with the large, aggressive mothers.

Additionally, black bears will eat salmon, suckers, American alligator eggs, crayfish, and trout and will seek out food within orchards, beehives, and agricultural croplands. They may frequently raid garbage dumps, campsites, or appropriate food from the trash bins of businesses or private homes.

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.

Hibernation

Mother black bear and cubs, hibernating
Black Bears enter their dens to Hibernate in October and November. Before that time, they typically put on an average of 4 lbs. of body fat, to get them through the seven months during which they do not eat. During this time, their heart rate drops from 98 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 hibernation, and the waste buildup would poison them if it were not removed, 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. While they do not eat, drink, defecate, or urinate during hibernation, they do not hibernate in the same manner as smaller mammals. Their body temperature does not drop significantly (It stays around 35 degrees Celsius) and they remain somewhat alert and active. If the winter is mild enough, they may not enter hibernation at all. The footpads peel off while they sleep, making room for new tissue. After emerging from their winter dens in spring, they 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. 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 and rivers as travel corridors.

Interspecific predatory relationships

In some areas, Black Bears share their range with brown bears. Due to their smaller size, Black Bears are at a competitive disadvantage against brown bears in open, non-forested areas. Although displacement of black bears by Brown Bears has been documented, actual interspecific killing of Black Bears by brown bears has only occasionally been reported. The diurnal Black Bear's habit of living in heavily forested areas as opposed to the largely nocturnal brown bear's preference for open spaces usually ensures that the two species avoid confrontations in areas where they are sympatric.

Black Bears are also sympatric with cougars and may compete with them over carcasses. Like Brown Bears, they will sometimes steal kills from cougars. One study found that both bear species visited 24% of cougar kills in Yellowstone and Glacier National Parksmarker, usurping 10% of carcasses. However, Black Bears and cougars rarely engage in violent combat with each other and usually try to scare each other with bluff charges, growls, swipes, etc.

Black Bear interactions with wolves are much rarer than with Brown Bears, due to differences in habitat preferences. The majority of Black Bear encounters with wolves occur in the species' northern range, with no interactions being recorded in Mexico. Despite the black bear being more powerful than a single wolf, packs of wolves have been recorded to kill Black Bears on numerous occasions without eating them. Unlike Brown Bears, Black Bears frequently lose against wolves in disputes over kills. Wolverines have challenged Black Bears over carcasses, but the much larger bear will sometimes kill the wolverine if the conflict turns to violence. The American Alligator has been recorded as preying on Black Bears, mainly cubs, on rare occasions. When possible, adult Black Bears (especially large males) are typically avoided by non-bear predators, especially if the confrontation takes place face-to-face. However, Black Bears themselves are usually timid and prefer to flee rather than fight.

Relationships with humans

Black bear at a garbage dump.

Livestock and crop damage

Livestock depredations by black bears occur mostly in spring. A limitation of food sources in early spring and wild berry and nut crop failures during summer months are probably major contributing factors. black bears can do extensive damage in some areas of the northwestern states by stripping the bark from trees and feeding on the cambium.

Though black bears will attack adult cattle and horses, they seem to prefer sheep, goats, calves, and pigs. They normally kill by biting the neck and shoulders, though they may break the neck or back of prey with blows from the paws. Evidence of a bear attack includes claw marks and is frequently being found on the neck, back, and shoulders of larger animals. Surplus killing of sheep and goats are relatively common. Bears have been known to frighten livestock herds over cliffs, causing injuries and death to many animals; whether or not this is intentional is not known.

Attacks on humans

Like many animals, they seldom attack unless cornered, threatened, wounded or to protect their young. They are less likely to attack humans than grizzly bears and typically flee for cover as soon as they identify a human visitor. Deaths by black bear, though, are most often predatory, while the more numerous grizzly fatalities on humans are often defensive. This makes feigning death when a black bear attacks ineffective. Although 16 North Americans have been killed since the year 2000, it is estimated that there have been only 56 documented killings of humans by black bears in North America in the past 100 years.

History and controversy

Irish Guards, wearing bearskins
Because little of their behavior has been understood until recently, Black Bears have been feared and hated. Before the 20th century, these bears were shot intermittently as vermin, food, and trophies, being seen as either a vicious beast or an endless commodity; until recently, in many areas, bounties were paid for Black Bears. Despite conservationists' demands to the contrary, the bearskin hats made of Black Bear fur are still used by regiments of many nations, including the five infantry regiments of the British Army's Brigade of Guards Foot Guards.

Paradoxically, Black Bears have also been portrayed as harmless and cuddly. For example, the teddy bear owes its existence to a young Black Bear cub Theodore Roosevelt refused to shoot, and Christopher Robin Milne named his teddy Winnie-the-Pooh after Winnipeg, a Black Bear which he and his father often saw at London Zoomarker. Today, Black Bears are as much an important game species as they are a point of debate across the continent, especially when many bears are finding life in the suburbs quite comfortable. Given their relatively low reproductive rate, Black Bear hunting must be carefully controlled and is probably inappropriate in areas where populations are feeble or where habitat is no longer intact.

The combination of bears' tendency to follow their stomachs and habitat encroachment by humans have created human-bear conflicts. This is especially true in areas where they may have been uncommon or absent for a long time, as in many parts of the eastern United Statesmarker. In New Jerseymarker, now the nation's most densely populated state, bears were quite common before the modern era. Because so much land was cleared for homes and farming and as a result of poor policies regarding hunting and forestry, by 1970 only about 100 bears remained. However, because of changes in land use, management, and bear population increases in neighboring Pennsylvaniamarker and New Yorkmarker, that number increased to an estimated 3,529 by 2003. In recent years, residents have increasingly encountered bears near their homes and workplaces. Attacks can happen when a bear has lost its fear of humans and has come to associate people with food. Similar events have unfolded in other states and in Canada. The rate of contact between Black Bears in search of food and humans rose to record levels in the western United States in autumn 2007. State, provincial, and federal agencies are working to address the issue with trap-and-release programs, limited hunting, and hazing bears with rubber bullets, other aversion techniques, and dogs. In agricultural areas, electric fences have been very effective.

Legal status

Captive Black Bears at a zoo in Florida
Today, a major threat to the American Black Bear is poaching, or illegal killing, to supply Asian markets with bear galls, hearts, and paws, considered to have medicinal value in Chinamarker, Japanmarker, and Koreamarker. The demand for these parts also affects grizzly and polar bears. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (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. Perpetrators caught poaching or smuggling either item out of the United States or Canada may face very serious legal ramifications, and park rangers within both countries are charged with the protection of the bears under their jurisdictions up to and including arrest.

Bear parts from American Black Bears may wind up illegally in Chinese markets like the heart depicted above as native Asian bears' numbers decline.


Black Bears are abundant in most of the western states and in most of Canada, but its presence in the Midwest is uneven by comparison. For example, Ontariomarker is home to about 100,000 bears, and neighboring Quebecmarker contains at least as many. The Upper Midwest similarly has a healthy population; Minnesotamarker and Michiganmarker have populations of 30,000 and 20,000, respectively. However, the species is virtually absent from some of the other states in the region, such as Iowamarker, Kansasmarker, and Illinoismarker. Many Midwestern states have not had a native breeding population of bears since the turn of the 19th century or earlier.

Most populations east of the Mississippi River are seeing a marked, steady increase in population: bears are moving back into places where they typically have been absent for over a century as suitable habitat has returned. In eastern states with heavily wooded areas, populations are growing rapidly; in Pennsylvaniamarker, for instance, the bear population has reached 15,000, and in North Carolinamarker it has reached 11,000. The Florida Black Bear has also increased its numbers in recent decades; in 2004, the Florida Fish & Wildlife Commission estimated that 2,400 bears resided in the state. However, continued development may reduce connectivity between the already separated populations in Florida. The Louisiana subspecies continues to be at critically low levels, although several successful reintroduction projects have added bears to new areas of the state.

In 1992, the U.S. Fish and Wildlife Service listed the Louisiana Black Bear subspecies as "threatened" under the Endangered Species Act, meaning it could be in danger of extinction throughout all or a significant portion of its range in the near future. This threatened status includes the historic range of Louisiana, southern Mississippi and eastern Texas so all American Black Bears in this area, no matter their genetic make-up, are also protected by legislation owing to its close resemblance to this subspecies. The Florida Black Bear was denied protection under the Endangered Species Act in 1998 and 2004 due to its adequate protection and management by the State of Florida.

In Mexico, the indigenous Black Bear population is listed as endangered and is mostly limited to increasingly fragmented habitat in the mountainous northern parts of the country. Individuals from this area seem to have naturally recolonized parts of southern Texas and along the Rio Grandemarker.

Miscellaneous

  • There has been considerable evidence of Black Bear activity that seems to suggest that the population may be extending its range back into historical territories in Ohio, Kentucky, Texas, and other areas where bears were eradicated and have not been present for a considerable amount of time. It is suspected that adolescent males seeking new territory are wandering far and wide, literally hundreds of miles, by following natural and manmade corridors (rivers and highways) back into their ancestral lands. It has generally been recent policy that if the animal does not become a nuisance, is not a danger, or is not in any imminent peril, that it be allowed to exist unmolested and without hindrance. Most cases remain out of the general public's knowledge until there has been a significant human-bear encounter. Note that while dispersing male bears wander far, females generally stay near where they were born. Because of this, although bears may show up in unexpected places, reproducing populations are slower to expand from core areas.
  • The sports teams of the University of Mainemarker are known as Black Bears; it is also the mascot for Baylor Universitymarker where two bears are kept on campus.
  • Ursus americanus kermodei, commonly known as the spirit bear, is a rare white (not albino) subspecies found in temperate rain forests on the Pacific coast of North America. Native tradition credits these animals with supernatural powers.
  • Smokey Bear, mascot of the United States Forest Service is based on an actual Black Bear cub found in New Mexicomarker after a forest fire. The Black Bear is also the state animal for New Mexico.
  • In August 2004, several news media outlets reported that a wild Black Bear was found passed out after drinking about 36 cans of beer in Baker Lake, Washingtonmarker, USA. 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 but one Buschmarker beer unconsumed.
  • The North American Bear Center, located in Ely, Minnesotamarker, is home to the world's largest captive male and female black bears. Ted, the male, weighed in the Fall of 2006. Honey, the female, weighed in the Fall of 2007. Both bears have a high protein diet.
  • Winnie-the-Pooh was named after Winnipeg the Bear, an orphaned black bear cub originally from the Canadian township of White River, Ontariomarker. During World War I, the bear was adopted by (then) Lieutenant Harry Colebourn, a member of The Royal Winnipeg Rifles of the Canadian Infantry. It later became the mascot for the company and was moved to London Zoomarker where it was seen by A. A. Milne and his son.
  • The Black Bear, a two-part 2/4 march, is a famous traditional tune played by Pipe bands around the world; it is the traditional march for Scottish soldiers returning to barracks at the end of the day. It is traditionally played at the end of each performance of the Edinburgh Military Tattoo.
  • The Black Bear is sometimes pursued by smaller animals. In newspapers on June 11, 2006, the Associated Press ran a photograph from West Milford, New Jerseymarker, of a Black Bear treed by a woman's cat, a 15-pound tomcat named Jack. After she called the cat home, the bear descended from its perch, about 25 feet up in the tree, and ran off.
  • Black bears can be observed and photographed at the Vince Shute Wildlife Sanctuary in Orr, Minnesota. The sanctuary is run by the American Bear Association and is a seasonal home to more than 70 bears.
  • "Crooked Tree" is a novel by Robert C. Wilson about black-bear attacks in Michigan.
The average life span of American black bears is approximately 32 years. The famous Smokey the Bear lived to be 27 years old.

See also



References

  1. Bears of the World by Lance Craighead, Publisher: Voyageur Press, 2003, ISBN 0896580083, 9780896580084, 132 pages
  2. Hidden World of Black Bears, North American Black Bear Center
  3. http://scholar.lib.vt.edu/theses/available/etd-02698-201736/unrestricted/etd.pdf
  4. Efficacy of Black Bear Supplemental Feeding to Reduce Conifer Damage in Western Washington, Georg J. Ziegltrum, The Journal of Wildlife Management, Vol. 68, No. 3 (Jul., 2004), pp. 470-474
  5. Effects of Spring acorn availability on Black Bear diet, milk composition, and cub survival, John E. McDonald Jr.A, B and Todd K. Fuller, Journal of Mammalogy Article: pp. 1022–1028
  6. Ozoga, J. J., and R.K. Clute. 1988. Mortality rates of marked and unmarked fawns. Journal of Wildlife Management 52:549-551.
  7. Mathews, N. E., and W. F Porter. 1988. Black bear predation on white-tailed deer neonates in the central Adirondacks, Canadian Journal of Zoology 66:1241-1242.
  8. Schlegal. M. 1976, Factor affecting calf elk survival in north central Idaho. Western Association of State Game and Fish Commission 56:342-355.
  9. Franzmann. A. W. C. C, Schwartz and R.O. Peterson, Moose calf mortality in summer at Kenai Peninsula, Alaska. Journal of Wildlife Management 44:764-768
  10. http://www.nrmsc.usgs.gov/products/Predation_Papers.pdf
  11. Problems and Control - FAQ
  12. 403 Forbidden
  13. http://www.iowadnr.com/wildlife/pdfs/bear%20log%202003%20complete.pdf
  14. http://www.nps.gov/bibe/naturescience/bears.htm88
  • Bears, consulting editor Ian Stirling, Fog City Press, 1993.


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