American black bear: north american black bear, fact about the american black bear

The American Black Bear (Ursus americanus) is the most common bear species native to North America. It lives throughout much of the continent, from northern Alaska south into Mexico and from the Atlantic Ocean to the Pacific Ocean. This includes 41 of the 50 U.S. states, all Canadian provinces except Prince Edward Island, and some of Mexico. 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 2 MYA. 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.^[1] It is a close relative of the Asiatic Black Bear with which it is thought to share a European common ancestor.^[2]

Description

The American Black Bear usually ranges in length from 150 to 180 cm (5 to 6 feet) and typically stands about 76 to 91 cm (2.5 to 3 feet) at the shoulder.^[3] Standing up on its hind feet, a Black Bear can be up to 7 feet tall (2.12 m).^[4] Males are 33% larger than females.^[5] Females weigh between 40 and 180 kg (90 and 400 pounds); males weigh between 115 and 275 kg (250 and 600 pounds) [4]. Adult black bears can reach 300 kg (660 pounds) [5], but exceptionally large males have been recorded from the wild at up to 240 cm (95 inches) long and at least 365 kg (800 pounds). The biggest American Black Bear ever recorded was a male from North Carolina that weighed 881 lbs (400 kilograms).^[6] At the other extreme, very small adult bears can weigh as little as 39 kg (85 lbs) in females and 47 kg (103 lbs) in males.^[7] Cubs usually weigh 200 to 450 g (between 7 ounces and 1 pound) at birth. The adult has small eyes, rounded ears, a long snout, a large body, and a short tail. It has an excellent sense of smell. 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 Canada, the border being between Manitoba and Ontario). They occasionally have a slight V-shaped white chest blaze. The tail is 4.8 inches (12.12 cm) long.^[5]

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.^[8] Each paw has five long, strong claws used for tearing, digging, and climbing. When necessary, they can run at speeds up to 30 miles per hour (48 km/h) and are good swimmers.^[9] The ears of a black bear are larger and more erect than those of the brown bear, and it lacks a prominent shoulder hump. ^[10]

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. Black bears typically "hibernate" during winter in hollowed-out dens in tree cavities, under logs or rocks, in banks, caves, or culverts, and in shallow depressions. Dens are normally not reused from one year to the next. While they do not eat, drink, defecate, or urinate during hibernation, it is not the true hibernation of smaller mammals since their body temperature does not drop significantly and they remain somewhat alert and active. Females give birth and nurse their young while hibernating.

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.

Reproduction

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 5-7 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 4-5 years old (they have to be large enough to win fights with other males and be accepted by females). Mating is generally during summer, from mid-June to mid-August with some variation depending on latitude, but with 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 do not develop.

The cubs are generally born in January or February. They are very small, about 10-14 ounces, 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 bears start leaving their dens, the cubs are fur-balls of energy, inquisitive and playful. By this time, they are about 4 to 8 pounds (2-4 kg). When their mother senses danger, she grunts to the cubs to 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.

Cub survival is totally dependent on the skill of the mother in teaching her cubs what and where to eat, how to forage, where to den, and when and where to seek shelter from heat or danger.

Diet

Black bears are omnivores whose diet includes plants, meat, and insects. They are apex predators in North America, with the exception of areas where they coexist with the brown bear. The black bear eats a wide variety of foods, mainly herbs, nuts and berries. 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.^[11] They also commonly feed on spring acorns in Massachusetts.^[12]

They feed on carrion 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^[13] and the state of New York,^[14] black bears prey on white-tailed deer fawns. In addition they have been recorded preying on elk calves in Idaho^[15] and moose calves in Alaska.^[16]

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.^[17]

Interspecific predatory relationships

In some areas, Black Bears share their range with the Brown Bear. 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.^[18]

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 Parks, usurping 10% of carcasses.^[19] However, Black Bears and cougars rarely engage in violent combat with each other and usually try to scare each other with bluff changes, 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. 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.^[20] Black Bears are generally timid and prefer to flee rather than fight.

Relationships with humans

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.^[17]

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 are being frequently found on the neck, back, and shoulders of these 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.^[17]

Attacks on humans

Like many animals, they seldom attack unless cornered, threatened, or wounded. 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.^[21] This makes feigning death when a Black Bear attacks ineffective. Although 15 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

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 Queen of England's 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 Zoo. 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.

Their tendencies 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 States. An excellent example is the state of New Jersey. In New Jersey, 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 Pennsylvania and New York, that number increased to an estimated 3,529 by 2003. The result is that the residents increasingly encounter bears near their homes and workplaces. Education and precaution are needed, especially in areas such as New Jersey where bear encounters are a fairly new phenomena in recent history. Fear of bear attacks is a common concern for these residents. Attacks can happen when a bear has lost its fear of humans and has come to associate people with food. This is a cause for concern among civilians and scientists alike. 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.^[22] 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.

Taxonomy and subspecies ranges

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:

Legal status

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 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 (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.

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, Ontario is home to about 100,000 bears, with at least as many in neighboring Quebec, while the Upper Midwest has a very healthy population with 30,000 bears in Minnesota alone. In contrast, nearby places like Iowa, Kansas, and Illinois have virtually none. Many Midwestern states have not had a native breeding population of bears since the turn of the 19th century or earlier.^[23]^[24]^[25]

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 North Carolina there were 11,000 bears at last count in 2004, Pennsylvania estimates 15,000 bears currently, New Jersey (a heavily urbanized state) estimated 3,529 in 2003, and even tiny Rhode Island has seen evidence of bears moving into areas where they haven't been in decades. The Florida Black Bear has also seen increases in numbers in recent decades; in 2004, the Florida Fish & Wildlife Commission estimated over 2,400 bears were in the state. Unfortunately, not all is well. 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 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 Grande.^[26]

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. The American Black Bear is also protected by legislation in the affected states (Louisiana, Mississippi, and Texas), 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.

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