How many miles can a polar bear swim without stopping?

A 6-year-long study recently found that polar bears can swim for great distances. GPS collars were attached to 20 female bears, some with cubs. The swims documented lasted from 17 hours to nearly 10 days and covered between 33 and 427 miles (54 and 687 kilometers) in the southern Beaufort Sea above Canada and Alaska.

There are no earlier studies on polar bear swims, but there has not been enough open water in recent years for bears to swim such distances.

Polar bears rely on sea-ice in the Arctic to hunt their prey, seals, but this ice is melting earlier every year. Scientists fear that cubs especially will not survive long swims. Twelve of the 20 bears had cubs when the collars were fitted, but when 10 of the 12 were recaptured a year later, only 6 still had cubs.

U.S. Geological Survey (link below).