How Long Do Bears Live? Lifespan of Black, Brown and Polar Bears

Bear lifespans at a glance

Bears are long-lived for their size, and their slow breeding depends on it: a female may raise only a handful of litters in her life, so she needs many years to replace herself. The table gives commonly cited ranges for the three bears of North America.

These figures describe what is possible, not what is typical. In most wild populations, the average age at death is far lower than the maximum because so many bears die as cubs or young adults.

How long do black bears live?

American black bears can live more than 30 years, but in hunted populations the average age at death is often about 10 years. Animal Diversity Web notes that more than 90% of black bear deaths after the age of 18 months are caused by people, through hunting, vehicle collisions, illegal killing and the removal of bears that cause problems near homes.

Where bears are protected, they live much longer. The oldest known wild black bear was a radio-collared female in Minnesota that lived to about 39 years. In captivity, black bears commonly reach their late 20s or 30s.

How long do brown and grizzly bears live?

Brown bears, including the grizzly bears of North America and the brown bears of Europe and Asia, have a naturally long life. In lightly hunted populations, adults commonly live 20–30 years, and wild females have been seen raising cubs at 28, the oldest known age for a wild bear to reproduce. The oldest recorded wild brown bear was nearly 37.

In zoos and sanctuaries, brown bears often live into their 30s. The longest lifespans reported for any bear, about 47–50 years, come from captive brown bears, including a male called Andreas who lived at a bear sanctuary in northern Greece.

How long do polar bears live?

Polar bears can live 25–30 years in the wild, but few do. Adult survival is high in good years, yet young bears that have just left their mothers often struggle to catch seals and may starve. The oldest known wild polar bears were in their early 30s.

Captive polar bears have lived beyond 40. In the wild, climate change is making life harder: when sea ice breaks up earlier in summer, bears must survive longer on land without hunting seals, and this lowers survival, especially for cubs and older bears.

How do scientists tell a bear’s age?

Biologists usually age a bear by counting growth rings in a tooth. Each year a thin layer of cementum, a bone-like tissue, builds up around the tooth root, and summer and winter layers look different. When researchers capture a bear, they often remove a tiny premolar behind the canine that the bear barely uses, then slice it thinly and count the rings under a microscope.

Other clues, such as tooth wear, body size, scars and a grizzled muzzle, give only rough estimates. Long-term studies of radio-collared bears, where an animal is followed from cubhood to death, provide the most reliable lifespan records.

What kills bears in the wild?

The riskiest time in a bear’s life is its first year. Cubs die from starvation when food is scarce, from accidents and disease, and from attacks by adult male bears, which sometimes kill cubs so that the mother will breed again. Wolves, cougars and other predators take some cubs, too. Across North America, roughly 60% of black bear cubs survive their first year, and survival is often lower for brown bears. Find out more in what is a baby bear called?

Young bears that have just left their mothers face a second dangerous period. They must find their own range, often near people, and many are hit by cars or get into conflicts. Adult bears have few natural enemies, so for adults the main causes of death are usually human-related: legal hunting, poaching, vehicle collisions and removal of bears that become used to human food. In old age, worn teeth and poor condition make bears more likely to starve during a bad year or to lose fights with younger rivals.