Melting Arctic ice makes polar bears take long voyage, which kills half of offspring, the scientists from the U.S. Geological Survey (USGS).
"Climate change" knocks "the ice under the feet of a bear, forcing them to swim farther in search of food and suitable habitat" — said of the research, an expert on polar bears in the WWF Jeff York (Geoff York) in an interview with Washington Post .
A team of researchers led by USGS biologist Anthony Pagano (Anthony Pagano) has provided 68 bears collared with satellite transmitters and GPS-collected information about their movements in the period from 2004 to 2009.
Comparison with maps of routes bears ice in the Arctic has shown that the retreat of the ice causes the bears to make the long voyage to the detriment of the population: five of the 11 bears that had to sail away with the Cubs lost offspring.
Moreover, 20 of the 50 bears had to swim about 50 miles at a time. The largest recorded distance swimming is 685 miles, and the longest swim with only a few brief respite on the ice floes lasted about 13 days.
In the world there are 20 to 25,000 polar bears, this species is listed in the Red Book of the Arctic states and protected.