American Black Bear

The American black bear (Ursus americanus) is a medium-sized bear found only in North America. It is the continent's smallest and most widely distributed bear, and mostly lives in forested regions, though it may wander beyond the trees in search of food.

Adults are typically 120 to 188 cm long and 63 to 103.5 cm tall at the shoulder. Males usually weigh 60 to 300 kg, while females are lighter at 40 to 150 kg. They have broad skulls, narrow muzzles, small rounded ears, a short tail and short, curved claws.

Despite the name, the coat varies from white, blonde, cinnamon and brown to jet black. About 70% are black. Silvery-grey bears occur along parts of coastal Alaska and British Columbia, and the white Kermode bear lives on islands of western Canada.

American black bears are not closely related to brown bears or polar bears. Genetic studies suggest those three lines split from a common ancestor about 5 million years ago. The closest relative is the Asian black bear, and the two separated about 4 million years ago.

An early small bear called Ursus abstrusus may be the direct ancestor, and the American black bear evolved in North America. Early fossils from Pennsylvania look much like the Asian species.

They shared the continent with giant short-faced bears and other specialised bears that died out at the end of the Pleistocene. The American black bear's flexible, omnivorous habits are thought to be one reason it survived.

Historically they lived across most of North America's forested regions. Today they are mostly found in sparsely settled, forested areas, though they have been expanding into some new areas in recent decades.

American black bears are generally territorial and solitary, though they may gather at rich food sources such as spawning salmon. They mark territories by rubbing on trees and clawing the bark. Their sense of smell is about seven times more sensitive than a domestic dog's.

They are strong swimmers and good climbers, although climbing ability declines with age. They can be active at any time but mostly forage at night or around dawn and dusk. They can run at 25 to 30 mph and are very dexterous, able to open screw-top containers and door latches.

They communicate with tongue-clicking, grunting, a rumbling hum when at ease, and jaw-clicking or lip-popping as a warning.

Up to 85% of the diet is plants, along with insects, honey, fish and carrion. In autumn feeding becomes almost a full-time task. In cold regions they spend 3 to 8 months in dens, living off body fat. Females give birth there in late winter, usually to two or three cubs.

They usually avoid people and rarely attack, typically making mock charges and blowing noises. Most attacks happen where bears have grown used to people and food.

The average lifespan in the wild is about 18 years, and it is quite possible for wild bears to survive past 23. The oldest wild bear recorded reached 39 years, and the oldest in captivity 44.

Survival varies. Only about 60% of cubs survive their first year, and subadults have a lower chance of surviving than adults. Cubs can fall prey to animals such as bobcats, coyotes, cougars, wolves and other bears, and flooded dens may kill newborns.

Adults have few natural predators. Most deaths are caused by people, through legal hunting, poaching and road collisions. In one Nevada study, annual mortality was 0% in wilderness but 83% in developed areas.

Bears have notable hibernation physiology. Their bone mass does not change during hibernation, they lose muscle strength more slowly than inactive animals that do not hibernate, and they become temporarily insulin resistant in winter.

This is general awareness only, not veterinary advice. If you find an injured or unwell wild animal, contact a vet or a wildlife rescue.

Are American black bears always black?

No. Coats range from white and blonde to cinnamon, brown and jet black. About 70% are black, but only about half in the Rocky Mountains.

How long do American black bears live?

The average in the wild is about 18 years. Some live beyond 23, and the oldest wild record is 39 years.

Do American black bears really hibernate?

Yes. They den for 3 to 8 months depending on climate, and live off stored fat. Their body temperature stays around 35 degrees C, and they remain somewhat alert. In the warmest southern areas only pregnant females and mothers with yearlings den.

What do American black bears eat?

They are omnivores. Up to 85% of the diet is vegetation, such as shoots, berries and nuts, plus insects, honey, fish and carrion. Near people they may eat rubbish, birdseed and crops.

Are American black bears dangerous?

They typically avoid people and rarely attack. They are capable of killing a human, but serious injury is rare compared with brown bear encounters.

How can you tell an American black bear from a grizzly?

Grizzlies have a shoulder hump, larger size and a broader, more concave skull. Pale American black bears are sometimes mistaken for grizzlies.

A 54 kg American black bear was seen flipping rocks weighing over 140 kg with one foreleg.

They can learn visual colour tasks faster than chimpanzees and as fast as domestic dogs.

The largest wild American black bear on record was a New Brunswick male from 1972, estimated at about 500 kg in life.

White Kermode bears catch salmon about 30% more successfully than black-furred bears.

The fertilised eggs of a female do not implant until November, so cubs arrive in late winter inside the den.

The teddy bear gained popularity after a story about Theodore Roosevelt refusing to shoot a black bear cub, and Winnie-the-Pooh was named after a black bear cub called Winnipeg.