Study: Polar bears swimming more as sea ice retreats

SAN DIEGO, April 20 (UPI) -- Polar bears rely on sea ice -- using it as a place to rest and hunt. Unfortunately, there seems to be less and less of it every year.

Scientists with the University of Alberta, Climate Change Canada and the Zoological Society of San Diego tracked the movements of polar bears in the Beaufort Sea and Hudson Bay. The data suggests the predators tend to swim greater distances as ice disappears.

Arctic sea ice always melts in the summer, but increasingly, more of it is melting than usual. The sea ice minimum at the height of the summer season is getting smaller as the planet warms.

The telemetry data from the polar bear collars in the latest study suggests that reality is necessitating longer, more frequent swims.

In 2012, sea ice in the Arctic hit a record low. That year, the majority of adult females being tracked in the Beaufort Sea logged at least one swim longer than 31 miles.

Researchers published their data in the journal Ecography.

Polar bears are excellent swimmers, but life in the Arctic is hard and the name of the game is caloric conservation. The more energy a bear uses, the more food he or she has to hunt and eat.

"Recent studies indicate that swimming may be energetically costly to polar bears," study author Nicholas Pilfold, a postdoctoral fellow at San Diego Zoo Global, said in a news release. "Given the continued trend of sea ice loss, we recognize that an increased frequency in the need to engage in this behavior may have serious implications for populations of polar bears living around the Arctic Basin."