"Polar bears are capable of swimming vast distances, a potential survival skill needed in an Arctic environment where summer sea ice is vanishing, a study led by the U.S. Geological Survey showed on Tuesday."
"The study, published in the Canadian Journal of Zoology, tracked 52 female polar bears in the southern Beaufort Sea off Alaska. Between 2004 and 2009, a period of extreme summer-ice retreat, about a third of those bears made swims exceeding 30 miles in distance, according to the study results.
The 50 recorded ultra-marathon swims averaged 96 miles, and one bear was able to swim nearly 220 miles, according to the study results. The duration of the long-distance swims lasted from most of a day to nearly 10 days, according to the study.
The bears' movements were tracked using global positioning system collars. All the animals in the study were females because male polar bear necks are too thick for GPS-equipped collars, said Karen Oakley, a supervising biologist at the USGS Alaska Science Center."
Yereth Rosen reports for Reuters May 2, 2012.