From EarthWatch Radio: Too Far to Swim

by Bradford Lystra
"Polar bears are great swimmers, and part of their typical routine involves swimming between land and ice that's floating on the Arctic Ocean. The ice cover in the Arctic is shrinking as temperatures rise, and polar bears in some places are at the limits of their ability to swim long distances. A scientist with the U.S. government recently reported on four bears that drowned. It was the first time he'd seen that in 20 years of Arctic research." More at EarthWatch Radio.

Based on Charles Monnett's research, published in Polar Biology, and available on the OhioLINK Electronic Journal Center:
Monnett, Charles.  2006.  Observations of mortality associated with extended open-water swimming by polar bears in the Alaskan Beaufort Sea.
Polar Biology, vol. 29, no. 8 (July 2006): 681-687.

The World of the Polar Bear, by Robert Nosing, is a beautiful pictorial work with text and bibliography, now on the new book shelf. [photo of mom and cub is from Nosing's book]