Polar Bears: Life on the Ice

Last updated: October 25, 2026

Most bears live in forests and mountains. The polar bear lives on frozen ocean. It hunts, travels and often raises its cubs on the Arctic sea ice, and it's built for that life from nose to paws.

A bear of the sea ice

Polar bears depend on Arctic sea ice to survive. They use it as a platform to hunt, find mates, travel and sometimes make their dens. They spend so much of their lives on the ice and in the water that, under US law, they count as marine mammals, along with whales, seals, walruses and sea otters.

Wild polar bears live in just five countries: Canada, the United States (Alaska), Russia, Greenland and Norway. About two-thirds of them live in Canada.

And no, they don't hunt penguins. Polar bears live in the Arctic, while wild penguins live almost entirely in the Southern Hemisphere. The two only meet in cartoons.

A big, big bear

Polar bears are among the largest bears in the world. Adult females usually weigh about 330 to 640 pounds (150 to 290 kg). Big males can weigh over 1,300 pounds (600 kg), roughly twice as much as females. Only the biggest brown bears, like the Kodiak bears of Alaska, come close.

How a polar bear hunts

Polar bears live mostly on seals, especially ringed and bearded seals, not on fish. What they really want is the fat. A polar bear can eat more than 100 pounds (45 kg) of blubber in one sitting.

Their nose does a lot of the work. Ringed seals rest in dens hidden under the snow on top of the sea ice. Researchers found that polar bears often walk across the wind so they can catch the scent of seals and track them down. Bears also wait at holes in the ice where seals come up to breathe.

Built for the cold

• Two layers of fur. A polar bear's fur keeps it so warm that adult males can quickly overheat when they run. That's one reason polar bears usually walk slowly.
• Fur that isn't really white. Each hair is transparent and hollow inside. It scatters light, which makes the fur look white.
• Black skin. Under all that fur, a polar bear's skin is black.
• Non-slip paws. The pads of the paws are covered in small, soft bumps that grip the ice and keep the bear from slipping.

Champion swimmers

In the water, a polar bear's big front paws work like paddles, and its back paws steer like rudders. They can swim very long distances. One polar bear was tracked swimming 427 miles (687 km) over about nine days.

Living off fat

When the sea ice melts and seals are hard to reach, polar bears live off the fat they've stored. Some can go for months without eating. Pregnant females in Canada's Hudson Bay have been found to fast for up to eight months.

Winter: who sleeps and who doesn't

Most polar bears don't hibernate. Males and females that aren't pregnant stay active and keep hunting through the Arctic winter.

Only pregnant females settle into snow dens. Snow covers the den's entrance, and the mother's body heat can keep it up to about 45°F (25°C) warmer than the air outside. Read more about winter dens in Do Bears Really Hibernate?

Cubs in the snow

Polar bear cubs are born in the den in winter, weighing only about 1 pound (500 g). Their mother's milk is the fattiest of any land animal, about 31 percent fat, so they grow fast. By two to three months, they weigh about 24 to 31 pounds (11 to 14 kg).

The family stays in the den until around March, when the cubs see sunlight for the first time and head out onto the ice with their mother.

Why the melting ice matters

Because polar bears hunt from the sea ice, they need it to get enough food. As the Arctic warms, the ice is melting earlier and forming later, and that's the biggest problem polar bears face. Less ice means less time to hunt seals and longer stretches of living off their fat.

Quick facts

My cousin up north eats nothing but seal fat and still looks great. Don't ask him for his secret. He'll just say "the ice."