Thursday, July 21, 2011

Longest Polar Bear Swim Recorded—426 Miles Straight, cubs drown along way

A female polar bear swam for a record-breaking nine days straight, traversing 426 miles (687 kilometers) of water—equivalent to the distance between Washington, D.C., and Boston, a new study says.

The predator made her epic journey in the Beaufort Sea (see map), where sea ice is shrinking due to global warming, forcing mother bears to swim greater and greater distances to reach land—to the peril of their cubs.

The cub of the record-setting bear, for instance, died at some point between starting the swim and when the researchers next observed the mother on land. She also lost 22 percent of her body weight.

"We're pretty sure that these animals didn't have to do these long swims before, because 687-kilometer stretches of open water didn't occur very often in the evolutionary history of the polar bear," said study co-author Steven Amstrup, chief scientist for the conservation group Polar Bears International. Amstrup is also the former project leader of polar bear research for the U.S. Geological Survey (USGS), which led the new study.

Another female bear in the study swam for more than 12 days, but appears to have found places to rest during her journey. (more)