The skulls of American black bears are broad, with narrow muzzles and large jaw hinges. In Virginia, the length of adult bear skulls was found to average .

Their claws are short and curved, being thickest at the base then tapering to a point, and most often black or grayish-brown in color. Claws from both hind and front legs are almost identical in length, though the curvature of foreclaws tends to be greater. The paws of the species are relatively large, with the forepaws measuring by and the hindpaws by , which is proportionately larger than other medium-sized bear species, but markedly smaller than those of large adult brown bears, and even more so, polar bears. The soles of the feet are black or brownish and are naked, leathery and deeply wrinkled.

The hind legs are relatively longer than those of Asian black bears. The typically small tail is . The ears are small and rounded, as well as being set well back on the head.

American black bears are highly dexterous, being capable of opening screw cap containers and manipulating door latches. They also have great physical strength; a bear weighing was observed flipping over flat rocks weighing with a single foreleg. They move with a rhythmic, sure-footed gait and can run at speeds of up to . American black bears have good eyesight and have been proven experimentally to be able to learn visual color discrimination tasks faster than chimpanzees and just as fast as domestic dogs. They are also capable of rapidly learning to distinguish different shapes, such as small triangles, circles and squares.

Size

thumb|left|260px|A cinnamon-colored American black bear in [[Yellowstone National Park, the U.S.]]

Adults typically range from in head-and-body length, and in shoulder height. Seasonal variation in weight is very pronounced: in autumn, their pre-den weight tends to be 30% higher than in spring, when black bears emerge from their dens. Bears on the East Coast tend to be heavier on average than their West Coast counterparts, although they typically follow Bergmann's rule regarding average size being inversely correlated with environment temperature, and bears from the northwest are often slightly heavier than the bears from the southeast.

In California, studies indicate that the average adult mass is in males and in females. In Great Smoky Mountains National Park, adult males averaged and adult females averaged per one study.

In one of the largest studies on regional body mass, bears in British Columbia averaged in 89 females and in 243 males. In Yellowstone National Park, a study found that adult males averaged and adult females averaged . Black bears in north-central Minnesota averaged in 163 females and in 77 males. In New York, the males average and females . It was found in Nevada and the Lake Tahoe region that bears closer to urban regions were significantly heavier than their arid-country dwelling counterparts, with males near urban areas averaging against wild-land males which averaged whereas peri-urban females averaged against the average of in wild-land ones. In Waterton Lakes National Park, Alberta, adults averaged .

The biggest wild American black bear ever recorded was a male from New Brunswick, shot in November 1972, that weighed after it had been dressed, meaning it weighed an estimated in life and measured long. Another notably outsized wild American black bear, weighing in at , was the cattle-killer shot in December 1921 on the Moqui Reservation in Arizona. The Pennsylvania state record weighed and was shot in November 2010 in Pike County. The North American Bear Center, located in Ely, Minnesota, is home to the world's largest captive male and female American black bears. Ted, the male, weighed in the fall of 2006. Honey, the female, weighed in the fall of 2007.

Pelage

thumb|upright=0.95|A white-colored [[spirit bear ]]

The fur is soft, with dense underfur and long, coarse, thick guard hairs. The fur is not as shaggy or coarse as that of brown bears. American black bear skins can be distinguished from those of Asian black bears by the lack of a white blaze on the chest and hairier footpads. Black coats tend to predominate in humid areas, such as Maine, New England, New York, Tennessee, Michigan and western Washington. Approximately 70% of all American black bears are black, though only 50% in the Rocky Mountains are black. Many in northwestern North America are cinnamon, blonde or light brown in color and thus may sometimes be mistaken for grizzly bears. Grizzly (and other types of brown) bears can be distinguished by their shoulder hump, larger size and broader, more concave skull.

In his book The Great Bear Almanac, Gary Brown summarized the predominance of black or brown/blonde specimens by location:

{| class="wikitable" style="float: left; width: 30rem;"

|+ Color variations of American black bears by location

! scope="col" style="width: 13rem;" | Location

! Color breakdown

|-

! scope="row" | Michigan

| style="padding-left: 1.25em;" | 100% black

|-

! scope="row" | Minnesota

| style="padding-left: 1.25em;" | 94% black, 6% brown

|-

! scope="row" | New England

| style="padding-left: 1.25em;" | 100% black

|-

! scope="row" | New York

| style="padding-left: 1.25em;" | 100% black

|-

! scope="row" | Tennessee

| style="padding-left: 1.25em;" | 100% black

|-

! scope="row" | Washington (coastal)

| style="padding-left: 1.25em;" | 99% black, 1% brown or blonde

|-

! scope="row" | Washington (inland)

| style="padding-left: 1.25em;" | 21% black, 79% brown or blonde

|-

! scope="row" | Yosemite National Park

| style="padding-left: 1.25em;" | 9% black, 91% brown or blonde

|}

Behavior and life history

Their keenest sense is smell, which is about seven times more sensitive than a domestic dog's. They are excellent and strong swimmers, swimming for pleasure and to feed (largely on fish). They regularly climb trees to feed, escape enemies and hibernate. Four of the eight modern bear species are habitually arboreal (the most arboreal species, the American and Asian black bears and the sun bear, being fairly closely related). Their arboreal abilities tend to decline with age. They may be active at any time of the day or night, although they mainly forage by night. Bears living near human habitations tend to be more extensively nocturnal, while those living near brown bears tend to be more often diurnal. They mark their territories by rubbing their bodies against trees and clawing at the bark. Annual ranges held by mature male bears tend to be very large, though there is some variation. On Long Island off the coast of Washington, ranges average , whereas on the Ungava Peninsula in Canada ranges can average up to , with some male bears traveling as far as at times of food shortages. American black bears often mark trees using their teeth and claws as a form of communication with other bears, a behavior common to many species of bears.

Reproduction and development

Sows usually produce their first litter at the age of 3 to 5 years, with those living in more developed areas tending to get pregnant at younger ages. The breeding period usually occurs in the June–July period, though it can extend to August in the species' northern range. The breeding period lasts for two to three months. Both sexes are promiscuous. Males try to mate with several females, but large, dominant ones may violently claim a female if another mature male comes near. Sows tend to be short-tempered with their mates after copulating.

The fertilized eggs undergo delayed development and do not implant in the female's womb until November. The gestation period lasts 235 days, and litters are usually born in late January to early February. Litter size is between one and six cubs, typically two or three. At birth, cubs weigh and measure in length. They are born with fine, gray, down-like hair and their hind quarters are underdeveloped. They typically open their eyes after 28–40 days and begin walking after 5 weeks. Cubs are dependent on their mother's milk for 30 weeks and will reach independence at 16–18 months. At 6 weeks, they attain , by 8 weeks they reach and by 6 months they weigh . They reach sexual maturity at 3 years and attain their full growth at 5 years.

Longevity and mortality

thumb|A female with cubs in [[Parc Omega, Quebec]]

The average lifespan in the wild is 18 years, and it is quite possible for wild individuals to survive for more than 23 years. while that in captivity was 44 years. The average annual survival rate is variable, ranging from 86% in Florida to 73% in Virginia and North Carolina. Cubs tend to be more vulnerable to predation than adults, with known predators including bobcats, coyotes, cougars, gray wolves, brown bears and other bears of their own species. Flooding of dens after birth may also occasionally kill newborn cubs. Bear fatalities are mainly attributable to human activities. Seasonally, thousands of black bears are hunted legally across North America, and some are illegally poached or trapped unregulated. Auto collisions also may kill many black bears annually. The physiology of American black bears in the wild is closely related to that of bears in captivity. Understanding the physiology of bears in the wild is vital to the bear's success in captivity.

The bears enter their dens in October and November, although in the southernmost areas of their range (i.e. Florida, Mexico, the southeastern United States), only pregnant females and mothers with yearling cubs will enter hibernation.

Hibernating bears spend their time in hollowed-out dens in tree cavities, under logs or rocks, in banks, caves, or culverts, and in shallow depressions. Although naturally-made dens are occasionally used, most dens are dug out by the bear. The bear keeping track of the changing days allows it to awaken from hibernation at the appropriate time of year to conserve as much energy as possible.

The hibernating bear does not display the same rate of muscle and bone atrophy relative to other nonhibernatory animals that are subject to long periods of inactivity due to ailment or old age. A hibernating bear only loses approximately half the muscular strength compared to that of a well-nourished, inactive human. The bear's bone mass does not change in geometry or mineral composition during hibernation, which implies that the bear's conservation of bone mass during hibernation is caused by a biological mechanism. During hibernation American black bears retain all excretory waste, leading to the development of a hardened mass of fecal material in the colon known as a fecal plug. Leptin is released into the bear's systems to suppress appetite. The retention of waste during hibernation (specifically in minerals such as calcium) may play a role in the bear's resistance to atrophy.

The body temperature does not drop significantly, like other mammalian hibernators (staying around ) 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, American black bears consume 25–40% of their body weight. Researchers have found that bears have adaptive reversible insulin resistance. During their fattening phase bears become hypersensitive to insulin but in the winter they switch and become more insulin resistant, as well as activating anti-inflammatory genes to resist kidney damage.

Many of the physiological changes an American black bear exhibits during hibernation are retained slightly post-hibernation. Upon exiting hibernation, bears retain a reduced heart rate and basal metabolic rate. The metabolic rate of a hibernating bear will remain at a reduced level for up to 21 days after hibernation. After emerging from their winter dens in spring, they wander their home ranges for two weeks so that their metabolism accustoms itself to the activity. 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.

The time that American black bears emerge from hibernation varies. Factors affecting this include temperature, flooding, and hunger. In southern areas, they may wake up in midwinter. Further north, they may not be seen until late March, April, or even early May. Altitude also has an effect. Bears at lower altitudes tend to emerge earlier. Mature males tend to come out earliest, followed by immature males and females, and lastly mothers with cubs. Mothers with yearling cubs are seen before those with newborns.

Dietary habits

Generally, American black bears are largely crepuscular in foraging activity, though they may actively feed at any time. During summer, the diet largely comprises fruits, especially berries and soft mast such as buds and drupes.

During the autumn hyperphagia, feeding becomes virtually the full-time task. Hard mast becomes the most important part of the diet in autumn and may even partially dictate the species' distribution. Favored mast such as hazelnuts, oak acorns and whitebark pine nuts may be consumed by the hundreds each day by a single bear during the fall. American black bears are also fond of honey and will gnaw through trees if hives are too deeply set into the trunks for them to reach it with their paws. Once the hive is breached, the bears will scrape the honeycombs together with their paws and eat them, regardless of stings from the bees. Other fish, including suckers, trout and catfish, are readily caught whenever possible. Although American black bears do not often engage in active predation of other large animals for much of the year, the species will regularly prey on mule and white-tailed deer fawns in spring, given the opportunity. Bears may catch the scent of hiding fawns when foraging for something else and then sniff them out and pounce on them. As the fawns reach 10 days of age, they can outmaneuver the bears, and their scent is soon ignored until the next year. American black bears have also been recorded similarly preying on elk calves in Idaho and moose calves in Alaska.

Predation on adult deer is rare, but it has been recorded. They may even hunt prey up to the size of adult female moose, which are considerably larger than themselves, by ambushing them. They will readily consume eggs and nestlings of various birds and can easily access many tree nests, even the huge nests of bald eagles. Bears have been reported stealing deer and other game from human hunters.

Interspecific predatory relationships

Over much of their range, American black bears are assured scavengers that can intimidate, using their large size and considerable strength, and if necessary dominate other predators in confrontations over carcasses. However, on occasions where they encounter Kodiak or grizzly bears, the larger two brown subspecies dominate them. American black bears tend to escape competition from brown bears by being more active in the daytime and living in more densely forested areas. Violent interactions, resulting in the deaths of American black bears, have been recorded in Yellowstone National Park.

American black bears do occasionally compete with cougars 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 the carcasses. Another study found that American black bears visited 48% of cougar kills in summer in Colorado and 77% of kills in California. As a result, the cats spend more time killing and less time feeding on each kill.

American black bear interactions with gray wolves are much rarer than with brown bears, due to differences in habitat preferences. The majority of American black bear encounters with wolves occur in the species' northern range, with no interactions being recorded in Mexico. Despite the American black bear being more powerful on a one-to-one basis, packs of wolves have been recorded to kill black bears on numerous occasions without eating them. Unlike brown bears, American black bears frequently lose against wolves in disputes over kills. Wolf packs typically kill American black bears when the larger animals are in their hibernation cycle. Anecdotal cases of alligator predation on American black bears have been reported, though such cases may involve assaults on cubs. At least one jaguar (Panthera onca) has been recorded to have attacked and eaten a black bear: "El Jefe", the jaguar famous for being the first jaguar seen in the United States in over a century.

Relationships with humans

In folklore, mythology and culture

thumb|upright|[[Harry Colebourn and Winnipeg, the bear from which Winnie-the-Pooh got his name]]

thumb|right|A tame bear on a leash

Indigenous

Black bears feature prominently in the stories of some of North America's indigenous peoples. One tale tells of how the black bear was a creation of the Great Spirit, while the grizzly bear was created by the Evil Spirit. In the mythology of the Haida, Tlingit and Tsimshian people of the northwest coast, mankind first learned to respect bears when a girl married the son of a black bear chieftain. In Kwakwa̱ka̱ʼwakw 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 children. 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.

Sleeping Bear Dunes in Michigan is named after a Native American legend, where a female bear and her two cubs swam across Lake Michigan to escape a fire on the Wisconsin shore. The mother bear reached the shore and waited for her cubs, but they did not make it across. Two islands mark where the cubs drowned, while the dune marks the spot where the mother bear waited.

Anglo-American

Richard Steiff, the creator of the teddy bear, made the toy in 1902 under Margarete Steiff's felt goods company. The toys were brought to the US and gained mass popularity after a newspaper told the story of Theodore Roosevelt refusing to shoot a black bear cub tied to a tree.

The fictional character Winnie-the-Pooh was named after Winnipeg, a female cub that lived at the London Zoo from 1915 until her death in 1934.

A cub, who in the spring of 1950 was caught in the Capitan Gap Fire, was made into the living representative of Smokey Bear, the mascot of the United States Forest Service.

Terrible Ted was a de-toothed and de-clawed bear who was forced to perform as a pro wrestler and whose "career" lasted from the 1950s to the 1970s.

Clark's Bears, previously named Clark's Trading Post, is a visitor attraction in Lincoln, New Hampshire known for its trained bear shows since 1949.

The American black bear is the mascot of the University of Maine and Baylor University, the latter of which houses two live bears on campus.

Attacks on humans

thumb|left|upright|There were fewer bear attacks in parks and campgrounds after the introduction of bear-resistant garbage cans and other reforms.

Although an adult bear is quite capable of killing a human, American black bears typically avoid confronting humans. 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.

American black bears rarely attack when confronted by humans and usually only make mock charges, emit blowing noises and swat the ground with their forepaws. The number of attacks on humans is higher than those by brown bears in North America, but this is largely because black bears considerably outnumber brown bears. Compared to brown bear attacks, aggressive encounters with black bears rarely lead to serious injury. Most attacks tend to be motivated by hunger rather than territoriality and thus victims have a higher probability of surviving by fighting back rather than submitting. Unlike female brown bears, female American black bears are not as protective of their cubs and rarely attack humans in the vicinity of the cubs.

The majority of attacks happened in national parks, usually near campgrounds, where the bears had habituated too close to human proximity and food. It is not recommended to use unleashed dogs to deter bear attacks. Although large, aggressive dogs can sometimes cause a bear to run, if pressed, angry bears often turn the tables and end up chasing the dogs in return. A bear in pursuit of a pet dog can threaten both canid and human lives.

Hunting

The hunting of American black bears has taken place since the initial peopling of the Americas. The first piece of evidence dates to a Clovis site at Lehner Ranch, Arizona. Partially calcined teeth of a 3-month old black bear cub came from a roasting pit, suggesting the bear cub was eaten. The surrounding charcoal was dated to the Early Holocene (10,940 BP). Black bear remains also appear to be associated with early peoples in Tlapacoya, Mexico. Native Americans increasingly utilized black bears during the Holocene, particularly in the late Holocene upper Midwest, e.g., Hopewell and Mississippian cultures.

Some Native American tribes, in admiration for the American black bear's intelligence, would decorate the heads of bears they killed with trinkets and place them on blankets. Tobacco smoke would be wafted into the disembodied head's nostrils by the hunter that dealt the killing blow, who would compliment the animal for its courage.

He wrote that black bears were difficult to hunt by stalking, due to their habitat preferences, though they were easy to trap. Roosevelt described how, in the southern states, planters regularly hunted bears on horseback with hounds. General Wade Hampton was known to have been present at 500 successful bear hunts, two-thirds of which he killed personally. He killed 30 or 40 bears with only a knife, which he would use to stab the bears between the shoulder blades while they were distracted by his hounds. In 1992, untanned, fleshed and salted hides were sold for an average of $165.

In Canada, black bears are considered as both a big game and furbearer species in all provinces, save for New Brunswick and the Northwest Territories, where they are only classed as a big game species. There are around 80,900 licensed bear hunters in Canada. Canadian black bear hunts take place in the fall and spring, and both male and female bears can be legally taken, though some provinces prohibit the hunting of females with cubs, or yearlings. A Fairleigh Dickinson University PublicMind poll found that 53% of New Jersey voters approved of the new season if scientists concluded that bears were leaving their usual habitats and destroying private property. Men, older voters and those living in rural areas were more likely to approve of a bear hunting season in New Jersey than women, younger voters and those living in more developed parts of the state.

Meat

Bear meat had historically been held in high esteem among North America's indigenous people and colonists. According to the second volume of Frank Forester's Field Sports of the United States, and British Provinces, of North America:

Theodore Roosevelt likened the flesh of young American black bears to that of pork, and not as coarse or flavorless as the meat of grizzly bears. The most favored cuts are concentrated in the legs and loins. Meat from the neck, front legs and shoulders is usually ground into minced meat or used for stews and casseroles. Keeping the fat on tends to give the meat a strong flavor. As American black bears can have trichinosis, cooking temperatures need to be high in order to kill the parasites.

Bear fat was once valued as a cosmetic article that promoted hair growth and gloss. The fat most favored for this purpose was the hard white fat found in the body's interior. As only a small portion of this fat could be harvested for this purpose, the oil was often mixed with large quantities of hog lard.

Sources

Further reading

  • Wildlifeinformation.org: American Black Bear Conservation Action Plan