Polar bears are excellent swimmers, but their preferred habitat is on top of the ice that covers the arctic seas much of the year. That is where they mate, hunt and rear their young.
Life on sea ice
Sea ice is vital to polar bears. It provides a platform for them to hunt, live, breed, and in some cases, create maternal dens.
But sea ice is more than a simple platform: it is an entire ecosystem inhabited by plankton and micro-organisms, which support a rich food chain that nourishes seals, that in turn become prey for polar bears.
It is the very foundation and defining characteristic of the Arctic marine ecosystem.
Life off the sea ice
As sea ice decreases at a rate of about 4.6% a decade, some polar bears at the southern edges of the species' range are spending five to six months on land, with very few seals to eat.
Without sea ice and seals, polar bears are left to search for other food sources. This can lead them into communities, where garbage dumps, sled dog yards and human food storage offer easy pickings. Bears in communities often create conflict between bears and people – bears threaten the safety of people and their property. Communities, government and WWF are working together to keep both bears and people safe.
What's happening to sea ice?
As the climate warms, Arctic sea ice is disappearing. Almost every summer, the amount of remaining ice gets smaller. The oldest ice has essentially disappeared.