A polar bear swam continuously for over nine days, covering 687km (426 miles), a new study has revealed.
Scientists studying bears around the Beaufort sea, north of Alaska, claim this endurance feat could be a result of climate change.
Polar bears are known to swim between land and sea ice floes to hunt seals.
But the researchers say that increased sea ice melts push polar bears to swim greater distances, risking their own health and future generations.
In their findings, published in Polar Biology, researchers from the US Geological Survey reveal the first evidence of long distance swimming by polar bears (Ursus maritimus).
“This bear swam continuously for 232 hours and 687 km and through waters that were 2-6 degrees C,” says research zoologist George M. Durner.
“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.”
Although bears have been observed in open water in the past, this is the first time one’s entire journey has been followed.
By fitting a GPS collar to a female bear, researchers were able to accurately plot its movements for two months as it sought out hunting grounds.
The polar bear is the largest terrestrial carnivore, being more than twice as big as the Siberian Tiger. It shares the title of largest land predator (and largest bear species) with the Kodiak bear. Adult males weigh 350–680 kg (770–1500 lbs) and measure 2.4–3 m (7.9–9.8 ft) in length. Adult females are roughly half the size of males and normally weigh 150–249 kg (330–550 lb), measuring 1.8–2.4 metres (5.9–7.9 ft) in length. When pregnant, however, they can weigh as much as 499 kg (1,100 lb).
Polar Bear swimming underwater at San Diego Zoo.
As of 2008, the World Conservation Union (IUCN) reports that the global population of polar bears is 20,000 to 25,000, and is declining. In 2006, the IUCN upgraded the polar bear from a species of least concern to a vulnerable species. It cited a “suspected population reduction of >30% within three generations (45 years)”, due primarily to global warming. Other risks to the polar bear include pollution in the form of toxic contaminants, conflicts with shipping, stresses from recreational polar-bear watching, and oil and gas exploration and development. The IUCN also cited a “potential risk of over-harvest” through legal and illegal hunting.