Mammals · Ursids

Bears

Family Ursidae

Six of eight species threatened

Bears are mammals of the family Ursidae — large, stocky-legged animals with a long snout, shaggy hair, plantigrade paws carrying five non-retractile claws, and a very short tail. Diet spans the extremes of the order: the polar bear is almost entirely carnivorous, the giant panda eats almost nothing but bamboo, and the other six species are broad omnivores.

Classification

Kingdom: Animalia

Phylum: Chordata

Class: Mammalia

Order: Carnivora

Suborder: Caniformia

Family: Ursidae

Genera: Ursus, Ailuropoda, Melursus, Tremarctos, Helarctos

Living species: 8

Nearest relatives: Pinnipeds, mustelids

Species

Eight living species: American black bear, Asiatic black bear, brown bear, polar bear, giant panda, sloth bear, spectacled bear and sun bear.

Size

Sun bear around 60 lbs and 4 ft; polar and Kodiak brown bears exceed 1,500 lbs and stand over 9 ft upright.

Habitat

Every continent except Antarctica and Australia — Arctic tundra, boreal and temperate forest, dense rainforest and high mountains.

Description

Massive bodies, coarse heavy fur, relatively short limbs and an almost rudimentary tail. Thick fur insulates against the severe cold most species face.

Coat patterns

Polar, brown and American black bears have solid coats. Sun, sloth, spectacled and Asiatic black bears carry dark coats with pale chest and face markings.

Diet

Omnivorous, with the balance varying sharply by species — the polar bear is mostly carnivorous, the giant panda almost entirely herbivorous.

Senses

An acute sense of smell — among the keenest of any land mammal — paired with strong natural curiosity.

Paws

Plantigrade: bears walk on the soles of their feet, with five non-retractile claws on each paw.

Gestation

Roughly 6–9 months depending on species, extended by delayed implantation.

Birth & Litter Size

Typically 1–3 cubs, born tiny and helpless in a winter den — a newborn polar bear weighs about 1 lb.

Social Structure

Typically solitary, apart from courting pairs and mothers with cubs.

Life Span

Most species average around 25 years in the wild.

Did You Know?

Bears walk plantigrade — flat on the soles of their feet, like humans — which is why their tracks look startlingly human and why they can rise and stand upright with ease.

Did You Know?

The giant panda is a true bear, but it has almost entirely abandoned the family diet: bamboo makes up roughly 99 percent of what it eats, and it must eat 20–40 lbs of it a day.

Did You Know?

Polar bear fur is not white. Each hair is hollow and transparent, scattering light — and the skin underneath is black, to absorb what warmth the Arctic sun offers.