Melting Arctic Ice Forces Polar Bears to Swim Long Distances Without Rest
The rapid melting of sea ice in the arctic due to global warming is causing polar bears to undertake lengthy and dangerous long-distance swims in search of food, new study shows.
The study, which was published in the journal Ecography, shows that 70 percent of the polar bears being observed have covered a minimal distance of 49 kilometers swimming in 2012, a 25 increase in the number of bears who covered miles in 2004.
For the study, researchers observed 100 polar bears in Hudson Bay and Beaufort Sea between 2007 and 2012 to determine the migratory response of the polar bears to climate change.
The researchers, led by Canadian biologist Andrew Derocher, the co-author of the study, have observed a female polar bear swimming over 400 kilometers without rest for nine days in 2009. The polar bear was with her cub during the journey, but unfortunately the young and vulnerable cub didn't make it.
Another polar bear recorded over 700 kilometer of swimming resulting to a 20 percent loss of her body weight.
In a report from Washington Post, Derocher told the news site through a phone interview that "Ice is changing so quickly that we're finding the bears are getting caught in places where they're finally coming to the realization, 'I just can't stay here.'"
"These kinds of long-distance swims are not what they evolved to undergo," Derocher added.
According to a report from NH Voice, polar bears are naturally good swimmers, but they are not used to swimming for hours covering hundreds of kilometers. They can only swim about 2 kilometers per hour. This means that a 30-mile marathon swim would take them about 24 hours to finish.
Extensive swimming can also greatly affect polar bears. Adult polar bears can lose significant amount of body weight during their journey. Cubs and older polar bears are also at risk of having hypothermia resulting to their deaths.