Twelve polar bear facts, fact-checked
The polar bear (Ursus maritimus) is the largest land carnivore and the only bear classified as a marine mammal. Full profile in our polar bear guide.
1. Their fur is not white
Each hair is transparent and hollow. The coat looks white because the hairs scatter visible light.
2. Their skin is black
Black skin beneath absorbs solar heat once light reaches it.
3. They are marine mammals
Polar bears are legally and biologically classified as marine mammals because their entire life cycle depends on sea ice.
4. They smell seals over 30 km away
They can also detect a seal in a breathing hole under a metre of compacted snow.
5. Males can exceed 700 kg
Large males reach around 3 m standing, making this the largest land carnivore alive.
6. They are strong swimmers
One tracked bear swam continuously for nine days across more than 600 km of open water — a journey that becomes more common, and more costly, as ice retreats.
7. They do not hibernate
Only pregnant females den through winter. Other bears remain active year-round.
8. Seal blubber is the whole diet
Ringed and bearded seals supply the fat a polar bear needs. Terrestrial food cannot replace it — a bear on land is losing condition.
9. Their liver is toxic to humans
Vitamin A concentrations are high enough to cause serious poisoning, a hazard long known to Arctic peoples.
10. Cubs are born tiny
Around 600 g at birth, in a snow den, emerging in spring at roughly 10–12 kg.
11. They can overheat easily
Insulation is so effective that polar bears overheat when running, which is why they move deliberately and hunt by waiting.
12. Sea ice loss is the threat
Less ice means a shorter hunting season and longer fasting. The species is Vulnerable, and the mechanism is unusually direct.
Read the full polar bear wildlife guide for IUCN status, population context and sources — or donate to WARN to help fund the partner teams protecting wildlife on the ground.
