Grizzly Bear vs Polar Bear: What’s the Difference?
The main difference between grizzly bears and polar bears is that polar bears are marine hunters of the Arctic sea ice that eat mostly seals, while grizzlies are inland omnivores that eat roots, berries, insects, fish and meat. Polar bears are larger on average, with white-looking fur and a long neck. Grizzlies are brown with a shoulder hump and hibernate through winter.
| Grizzly Bear | Polar Bear | |
|---|---|---|
| Scientific name | Ursus arctos horribilis | Ursus maritimus |
| Lifespan | 20–25 years in the wild | 15–18 years typical in the wild; some reach 25–30 |
| Weight | 130–360 kg (290–790 lb) | 150–700 kg (330–1,540 lb) |
| Size | 0.9–1.1 m (3–3.6 ft) (shoulder height) | 1.0–1.6 m (3.3–5.2 ft) (shoulder height) |
| Top speed | 56 km/h (35 mph) | 40 km/h (25 mph) |
| Gestation / incubation | 180–250 days (6–8 months), including delayed implantation | 195–265 days (about 8 months), including delayed implantation |
| Diet | Omnivore | Carnivore |
| Family | Ursidae | Ursidae |
| Habitat | Mountain forest, Alpine meadow, Tundra, River valley, Prairie edge | Sea ice, Arctic coast, Tundra |
| IUCN status | Least Concern | Vulnerable |
Figures shown are for the grizzly bear (Ursus arctos horribilis) and the polar bear (Ursus maritimus).
Key differences
Diet
The polar bear is the most carnivorous of all bears. It depends on the fat of ringed and bearded seals, caught at breathing holes or on the ice. The grizzly eats almost anything: grasses, roots, berries, pine nuts, moths, salmon, carrion and the occasional elk calf. In many areas, plants make up most of its diet.
Habitat
Polar bears live around the Arctic Ocean, in Alaska, Canada, Greenland, Norway's Svalbard and Russia, and spend so much time on sea ice that they are classed as marine mammals. Grizzlies, a North American subspecies of the brown bear, live inland in forests, mountains and tundra from Alaska and western Canada to the northern Rockies.
Fur and skin
A polar bear's fur is not truly white. The hairs are transparent and hollow and scatter light, so the coat looks white or yellowish, while the skin underneath is black. Grizzly fur ranges from blond to nearly black, often with pale tips on the back and shoulders that create the 'grizzled' look.
Body shape
Grizzlies have a prominent hump of muscle over the shoulders that powers digging, a dished face and long, gently curved claws. Polar bears have no hump. They have a longer neck, a narrower head with a straight 'Roman' nose, smaller ears, and huge, partly webbed paws with shorter, sharper claws that grip ice.
Winter behavior
Grizzlies spend the cold months in a den, living off stored fat without eating or drinking. Most polar bears stay active all winter, because that is when seal hunting is best. Only pregnant females dig snow dens, where they give birth and nurse their cubs until early spring.
Conservation
The polar bear is listed as Vulnerable on the IUCN Red List, mainly because warming is shrinking the sea ice it needs for hunting. The brown bear as a species is of Least Concern globally, but grizzlies were wiped out across most of the contiguous United States and survive there in only a few protected populations.
How to tell them apart
- White or cream fur means polar bear; brown fur, often with silvery tips, means grizzly.
- Look for the shoulder hump. Grizzlies have one, and polar bears do not.
- A long neck and a narrow, straight-profiled head indicate a polar bear; a round, dished face indicates a grizzly.
- A bear on sea ice or an Arctic shoreline is almost certainly a polar bear.
What they have in common
Grizzlies and polar bears are very close relatives in the genus Ursus. Polar bears evolved from brown bear ancestors relatively recently in evolutionary terms. Both are huge, solitary animals with an extraordinary sense of smell, both can stand upright, and mothers of both species raise their cubs for more than two years. Both are surprisingly fast runners and capable swimmers.
Frequently asked questions
Who would win a fight, a grizzly or a polar bear?
It is uncertain. Polar bears are larger on average, but grizzlies are stockier and famously aggressive. Where the two meet at whale carcasses on Alaska's Arctic coast, observers have reported polar bears frequently giving way to grizzlies, though these encounters rarely become real fights.
Can grizzlies and polar bears interbreed?
Yes. The two produce fertile hybrids, nicknamed 'pizzly' or 'grolar' bears. A wild hybrid was first confirmed by DNA testing in the Canadian Arctic in 2006, and several more have been identified since. As grizzlies move north and sea ice declines, the two species meet more often.
Which is bigger, a grizzly or a polar bear?
The polar bear is bigger on average and is often called the largest land carnivore. Adult male polar bears typically outweigh inland grizzlies by a wide margin. The big coastal brown bears of Alaska and Kodiak Island, however, can match polar bears in size.
Which bear is more dangerous to humans?
Both are dangerous. Polar bears are more likely to view people as prey, but they live in remote areas, so attacks are rare. Grizzly attacks are more frequent because far more people hike in grizzly country; most are defensive, involving surprised bears or mothers with cubs.