Polar Bear vs Grizzly Bear

Overview

The polar bear, Ursus maritimus, and the grizzly bear, Ursus arctos, are both large northern bears. They can look broadly similar in silhouette, especially at distance, but their coat, head shape, paws, diet, and habitat tell a clearer story.

A polar bear is adapted to Arctic sea ice. Its long neck, relatively narrow head, thick blubber, water-repellent fur, and broad paws support travel over ice and swimming between it. A grizzly bear is adapted to land-based foraging, with a pronounced shoulder hump, long digging claws, and a diet that changes with season and place.

The two are close enough to hybridize where their ranges meet, but that biological fact should not erase the distinction between their normal ecological roles. A polar bear depends heavily on access to seals from sea ice; a grizzly bear uses a broad range of plants, fish, insects, and mammals on land.

Size

Polar bears measure about 6–9 feet and weigh 550–1,700 pounds. Grizzly bears measure roughly 5–8 feet and weigh 300–800 pounds. Adult polar bears can therefore reach a higher maximum mass, though individual size varies by sex, age, season, and local food supply.

Polar bears stand around 3.5–5 feet at the shoulder, compared with about 3–4 feet for grizzlies in the current profiles. The polar bear's longer neck and pale coat can make it look more elongated. A grizzly's shoulder hump is not fat; it is a mass of muscle that powers digging.

Both can move faster than most people expect over a short distance. The recorded top speed for a polar bear is up to 25 mph; the grizzly record reaches up to 35 mph in short bursts. Speed is not a safe basis for approaching or judging either animal.

Behavior

Polar bears are generally solitary hunters that travel across sea ice, wait near seal breathing holes, and swim long distances when conditions require it. Pregnant females use dens for birth, while other bears may range widely in search of ice-associated prey.

Grizzlies are also often solitary, but their behavior is structured around seasonal land foods. They may dig for roots, forage on berries, fish for salmon, eat insects, and build fat reserves before winter denning. Where concentrated food occurs, several grizzlies may tolerate one another at a distance without forming a permanent social group.

Both species scent-mark and raise cubs for an extended period. Their social lives are less group-centered than those of wolves or lions, but mothers and cubs remain closely connected.

Diet

Polar bears are carnivores whose recorded prey includes ringed, bearded, and harp seals, along with walrus calves and fish. Their role as a seal hunter links their survival to the timing and stability of sea ice, not merely to cold weather.

Grizzly bears are omnivores. Their profile includes berries, roots, salmon, insects, grasses, and small mammals. Some grizzlies take larger prey or scavenge, but the species is not a seal specialist and does not require sea ice to feed.

Diet is the most important ecological difference. A polar bear may look like a pale brown bear, but its core feeding system is marine. A grizzly is a land bear whose seasonal menu can be extremely varied.

Habitat

Polar bears occupy Arctic sea ice and adjacent coasts across North America and Europe in the WildlifeDB record. Sea ice functions as a hunting platform, a travel route, and access to important prey. Loss or earlier breakup of that ice can reduce feeding opportunity even when a bear remains on land.

Grizzlies use forest and other northern terrestrial habitats in North America. They need space, seasonal food, and secure denning areas. Their habitat may include mountains, river valleys, tundra edges, or coastal forests, but it is land-based rather than sea-ice dependent.

The polar bear is Vulnerable with a decreasing trend; the grizzly is Least Concern with a stable trend. Those global labels do not make every grizzly population secure, nor do they capture the speed of change in particular polar-bear regions.