LONDON: Scientists studying bears around the Beaufort Sea, north of Alaska, have revealed that a polar bear swam continuously for over nine days, which could be the result of climate change.

Scientists from the US Geological Survey revealed the first evidence of long distance swimming by polar bears after observing one that swam continuously for over nine days.

"This bear swam continuously for 232 hours and 687 km and through waters that were 2-6 degrees C," the BBC quoted research zoologist George M. Durner as saying.

"We are in awe that an animal that spends most of its time on the surface of sea ice could swim constantly for so long in water so cold. It is truly an amazing feat," he said.

Scientists were able to accurately plot a female bear's movements for two months by fitting a GPS collar to it, and as it sought out hunting grounds, they were able to determine when she was in the water through the collar data and a temperature logger implanted beneath her skin.

The data collected showed that the epic journey came at a very high cost to the bear.

"This individual lost 22 percent of her body fat in two months and her yearling cub. It was simply more energetically costly for the yearling than the adult to make this long distance swim," he explained.

Durner went on to say that conditions in the Beaufort Sea, north of Alaska, have become increasingly difficult for polar bears.

"In prior decades, before 1995, low-concentration sea ice persisted during summers over the continental shelf in the Beaufort Sea," he stated.

"This means that the distances, and costs to bears, to swim between isolated ice floes or between sea ice and land was relatively small.

"The extensive summer melt that appears to be typical now in the Beaufort Sea has likely increased the cost of swimming by polar bears," he said.

Polar bears live within the Arctic Circle and eat a calorie-rich diet of ringed seals to survive the frozen conditions, and they hunt for their prey on frozen sea ice.

"This dependency on sea ice potentially makes polar bears one of the most at-risk large mammals to climate change," Durner added.

The findings have been published in Polar Biology.