Polar Bear
Ursus maritimus
A bear that officially counts as a marine mammal — because it lives on the sea.
The polar bear is the biggest bear alive, and it's classed as a marine mammal, just like the whales and seals on this site. That's because it depends on the ocean: it lives on the floating sea ice of the Arctic and hunts seals from it. Its scientific name, Ursus maritimus, means sea bear.
On the conservation status
Listed as Vulnerable by the IUCN, mainly because the sea ice it hunts from is shrinking as the Arctic warms. The United States lists it as Threatened for the same reason.
- Length
- Males 2.4–3 m (8–10 ft)
- Weight
- Males 270–540 kg; females 180–320 kg
- Lifespan
- About 25 years
- Diet
- Mostly ringed and bearded seals
- Population
- About 26,000, in 19 groups
- Range
- The sea ice all around the Arctic
The good stuff.
Officially a marine mammal
Polar bears depend on the sea ice over the Arctic Ocean, so in the United States they're protected by the same law as whales and seals: the Marine Mammal Protection Act. The agency that looks after them also looks after walruses, sea otters and manatees.
Waiting at the breathing hole
Ringed seals are their main food. Seals keep holes open in the ice so they can come up to breathe, and a polar bear catches them by waiting beside one.
Not fussy when it's hungry
Besides ringed seals, polar bears eat bearded seals, walruses and even beluga whales. When none of those are around, they'll eat dead animals they find, and sometimes plants.
Built for ice and water
Compared with other bears, polar bears have longer necks, narrower heads and smaller ears. Their huge feet are almost covered in fur, which helps them paddle and grip the ice.
Tiny cubs, born in a den
Cubs are born in December or January weighing just 0.5–1 kg (1–2 lb), usually as twins. They don't come out of the den until late March or April, when they weigh about 9–11 kg, and they stay with their mother until they're about two.
The long swim
In 2008 scientists tracking a female polar bear watched her swim non-stop for 687 km over nine days, then keep walking and swimming another 1,800 km across the ice. They found long swims like hers happen most in years when the summer sea ice has melted far back.
Wait, really?
- ✦
There are 19 separate groups of polar bears, spread across Canada, the United States, Greenland, Norway and Russia.
- ✦
Its coat can look white or yellowish. It's water-repellent hair on top of a thick, dense undercoat.
- ✦
It's the largest bear species alive.
What it sounds like
Mostly quiet. Mothers and cubs chuff softly to each other, and an angry bear hisses, snorts and growls.
We haven't found a recording we're allowed to share yet, so for now this one is a description.
Where you might see one
Churchill, on Canada's Hudson Bay, and the Svalbard islands in Norway — always from a safe tour vehicle or boat.
The trouble
- Sea ice shrinking as the Arctic warms — the ice they hunt from
- Oil and gas drilling and more shipping in the Arctic
- Pollution building up in the Arctic food chain
One real thing
The biggest threat to polar bears is a warming planet melting their sea ice. Saving energy at home, and walking or biking instead of driving, are small steps in the right direction.
More ways to help