American black bear

Name and taxonomy

The scientific name Ursus americanus means simply American bear. It sits in the family Ursidae and the order Carnivora, though most of its food is plant matter. GBIF lists Baribal as a second English name, along with the Spanish oso negro americano and the French ours noir. A group of bears is sometimes called a sloth or a sleuth, though wild black bears probably rarely form one.

Sixteen subspecies have been named by tradition. A 2015 genetic study found no support for several of them, including the Florida black bear. The white Kermode bear of coastal British Columbia is a colour form of one subspecies, not a separate species. The black bear is not a close relative of the brown bear or the polar bear, even though all three share the continent.

Evolution and relatives

The black bear line split from the brown bear and polar bear line about 5.05 million years ago. Its nearest living relative is the Asian black bear, and the two parted about 4.08 million years ago. Before that, their shared ancestor had left the sun bear line about 4.58 million years ago. A small early bear, Ursus abstrusus, is the oldest member of the genus in North America, at 4.95 million years.

The earliest fossils of the species, from Port Kennedy in Pennsylvania, look much like the Asian species. Later Pleistocene animals grew as large as grizzlies. The black bear shared the continent with the giant short-faced bear and the Florida spectacled bear. Those bears died out at the end of the last ice age, while the black bear survived, probably because it ate almost anything. In 1859 a black bear and a brown bear produced three cubs at London Zoo, but none reached adulthood.

Appearance

The black bear has a broad skull, a narrow muzzle, small rounded ears set well back, and a short tail of 7.7 to 17.7 centimetres. The face runs straight or slightly convex from the forehead to the nose. A grizzly has a dished face, a shoulder hump and a larger body, which is the easiest way to tell the two apart. The claws are short, curved and dark, and the front claws curve more than the hind ones. The soles are bare, black and deeply wrinkled.

Head and body length runs from 120 to 188 centimetres, and shoulder height from 63 to 103.5 cm. Males weigh 60 to 300 kilograms, and females weigh about a third to a half less, 40 to 150 kg. Weight swings with the season: a bear enters its den about 30% heavier than it leaves it. The largest wild male on record, shot in New Brunswick in 1972, weighed 409 kg after dressing and was 2.41 metres long.

The fur is soft, with dense underfur under long guard hairs. About 70% of black bears are black, but only half of those in the Rocky Mountains are. Cinnamon, brown and blonde bears are common in the northwest, and they are often mistaken for grizzlies. A blue-grey form lives on the Alaskan coast, and white Kermode bears live on the islands of British Columbia. Many bears carry a pale muzzle, and some carry a white spot on the chest.

Habitat and range

The species ranges from northern Alaska across Canada to Newfoundland, and south through the United States into central Mexico. It once lived in nearly every forested part of the continent. Today it holds most of its Canadian range, the whole Appalachian chain, the northern Midwest, the Rockies, the West Coast and Alaska. Bears have returned to Ohio, Illinois, Indiana and Nebraska in recent decades, and one settled in Iowa in 2019.

Black bears want three things from a place: rough ground, thick undergrowth and plenty of nuts or berries. In the lower 48 states they mostly live in wooded mountains between 400 and 3,000 metres. In the southwest that means chaparral and pinyon-juniper woodland, with trips into the open for prickly pear. In the southeast it means oak-hickory forest in the hills and swampy hardwoods on the coast. In the northeast, beech, maple and birch give food, and white cedar swamps give cover.

The taste for dense cover probably dates from a time when bigger bears and sabre-toothed cats held the open country. In Labrador, with no brown bears about, black bears live in open tundra and hunt caribou. Bears also live at the edge of towns wherever bins, bird feeders and orchards offer easy food.

Diet and feeding

Up to 85% of the diet is plant matter. In spring a bear leaves its den thin and looks for winter-killed carcasses, new grass and wetland shoots. In summer it turns to berries and other soft fruit. In autumn it eats almost without pause, and hazelnuts, acorns and pine nuts go down by the hundred each day. It raids squirrel nut stores and takes huckleberries and buffalo berries by the mouthful.

Most of the animal food is insects: ants, bees, wasps, beetles and their grubs. A bear will tear open a tree trunk to reach a hive and eat the comb through the stings. Coastal bears fish for salmon, mostly at night, because the fish spot a black shape by day. The white Kermode bears catch salmon 30% more often than their black neighbours.

The black bear is not a keen hunter, but it takes deer fawns in spring by scent while the fawns still lie hidden. After about 10 days the fawns can dodge a bear, and the bears lose interest. Young elk in Idaho and young moose in Alaska go the same way. Near people, bears eat rubbish, birdseed, corn, apples and honey from hives.

Behaviour and social life

Black bears live alone, except for mothers with cubs, mating pairs in summer and crowds at a rich food source. Where salmon run or a dump is open, many bears gather and a pecking order forms, with the largest males at the best spots. They are most active at dawn and dusk, but feed at any hour. Bears near towns turn nocturnal, and bears near brown bears turn diurnal.

A male's annual range can be small or huge. On Long Island in Washington it averages 13 square kilometres, and on the Ungava Peninsula up to 2,600 square kilometres. One male covered 11,260 square kilometres in a year of food shortage. Bears mark their ground by rubbing against trees and raking the bark with claws and teeth. They climb well, swim well and can open screw-top jars and door latches.

In October or November the bear enters a den it has usually dug itself, under a log, a rock or in a bank. Its heart slows from 40 to 50 beats per minute to about 8, and its metabolic rate can fall to a quarter of normal. Body temperature stays near 35 degrees Celsius, so the bear can wake and move if disturbed. It neither eats, drinks nor passes waste for the whole 3 to 8 months, and loses 25 to 40% of its weight. Its muscles and bones do not waste away as a resting human's would, which interests medical researchers.

Communication and senses

Smell is the bear's sharpest sense, about seven times keener than a dog's. Its eyesight is good, and in tests it learned to tell colours apart faster than chimpanzees and as fast as dogs. It can also learn to tell a triangle from a circle or a square.

Bears talk with sound, posture, touch and scent. Tongue clicks and grunts are friendly sounds, used with cubs, other bears and sometimes people. A relaxed bear gives a loud rumbling hum, and a nervous one moans, huffs or blows. Jaw clicks and lip pops are warnings, and a real threat brings a pulsing guttural call like a growl. Cubs squeal or bawl when upset and hum like a motor when they nurse. Claw and tooth marks on trees carry messages to the next bear that passes.

Reproduction and life cycle

Mating runs from June into July, and into August in the far north. Both sexes take several partners, though a big male may drive rivals off a female by force. The fertilised eggs do not implant until November, so gestation lasts about 235 days in all. Cubs arrive in late January or February, in the den, while the mother is still torpid. A litter holds 1 to 6 cubs, usually 2 or 3.

A newborn weighs 280 to 450 grams and is 20.5 centimetres long, blind and almost hairless. For its size, it is the smallest newborn of any placental mammal. The eyes open after 28 to 40 days, and the cub walks at about five weeks. By 8 weeks it weighs 2.5 kilograms, and by 6 months 18 to 27 kg. Cubs nurse for about 30 weeks and stay with their mother through a second winter, until 16 to 18 months.

A female first breeds at 3 to 5 years and then has cubs every second year if food allows. Males mature at 3 to 4 years but keep growing until 10 to 12, when size alone wins them fights. The average wild lifespan is about 18 years, and the wild record is 39. One captive bear reached 44 years.

Predators and threats

An adult black bear has few natural enemies, apart from a brown bear or a wolf pack. Wolves sometimes kill hibernating bears and leave them uneaten. In the far south a jaguar can ambush a bear, and the famous jaguar El Jefe ate one. Cubs face bobcats, coyotes, cougars, wolves, brown bears and other black bears, and one golden eagle took a yearling. About 60% of cubs survive their first year.

People are the main killer. ADW reports that over 90% of deaths after 18 months of age come from guns, traps or vehicles. A Nevada study found no adult deaths in wilderness but 83% annual mortality in developed areas. Roughly 18,000 bears were shot each year in the United States between 1988 and 1992. Flooded dens drown some newborn cubs.

Population and conservation

The IUCN lists the black bear as Least Concern, one of only two bears not thought to be at risk worldwide. A 2011 estimate put the United States population between 339,000 and 465,000, without Alaska and four other states. Canada held 396,000 to 476,000 bears in seven provinces in the mid 1990s. Surveys from 35 states in the early 1990s showed stable or rising numbers everywhere except Idaho and New Mexico.

California had 25,000 to 35,000 bears in 2017, the most of any of the lower 48 states. Great Smoky Mountains National Park held about 1,500 in 2020. Western North Carolina went from about 3,000 bears in the early 2000s to over 8,000 in the 2020s. Mexico is the one country that lists the species as endangered. The species sits on CITES Appendix II, which controls trade in its parts.

Relationship with humans

People have hunted black bears since the first Americans. A roasting pit at Lehner Ranch in Arizona held the teeth of a cub, with charcoal dated to 10,940 years ago. Quebec exported 192,000 bear skins in 1799. Today 28 states run bear seasons, and over 481,500 licences sell each year. Canada has about 80,900 licensed bear hunters.

The bear itself rarely attacks. It bluff charges, blows and slaps the ground, then usually leaves. ADW counts fewer than 36 deaths from black bears in the whole 20th century. The worst case came in May 1978, when one bear killed three teenagers in Algonquin Park, Ontario. Most attacks are about food, so fighting back beats playing dead. In the Great Smoky Mountains, 1,028 aggressive incidents from 1964 to 1976 caused 107 injuries, almost all where tourists fed bears.

Bears raid corn, oats and apples, strip bark from timber in the northwest, and kill sheep, goats and pigs in spring. Closing dumps and ending handouts cuts trouble almost every time. Moving a problem bear rarely works, because it walks home. Research into bear torpor is helping doctors treat kidney failure, gallstones and burns.

In culture and myth

In one Native American tale, the Great Spirit made the black bear and the Evil Spirit made the grizzly. In Haida, Tlingit and Tsimshian tradition, people learned respect for bears after a girl wed the son of a black bear chief. In Kwakwaka'wakw tradition, Grizzly Bear Woman killed Black Bear Woman for laziness, and the children took revenge. The Navajo prayed to the Big Black Bear, chief of the bears of the four directions, for protection on raids. Many nations treat the bear as a medicine animal, and the Cherokee see it as an elder and a guide.

Sleeping Bear Dunes in Michigan takes its name from a mother bear who swam Lake Michigan and waited for two cubs that drowned. Some tribes decorated the head of a killed bear, blew tobacco smoke into its nostrils and praised its courage.

The teddy bear began in 1902, after a newspaper told how Theodore Roosevelt refused to shoot a tethered black bear cub. Winnie-the-Pooh took his name from Winnipeg, a black bear cub at London Zoo from 1915 to 1934. Smokey Bear's living model was a cub rescued from the Capitan Gap Fire in 1950. Two universities, Maine and Baylor, use the black bear as their mascot, and Baylor keeps two live bears on campus.