Land-based foods won’t float polar bears through ice declines

This web exclusive appeared on hcn.org April 1, 2015:

The polar bear is the most carnivorous and gigantic of the ursids. No grizzly documented in Yellowstone has weighed more than 900 pounds. The largest male polar bears? In excess of 1,700 pounds. No wonder United States Geological Survey wildlife biologist Karyn Rode describes collecting samples and measurements from tranquilized polar bears as “surreal.” And yet, it wasn’t the bears per se that most captured her imagination when she arrived on the southern Beaufort Sea by helicopter in 2007 for her first field season. It was the fact that they manage to eke out their existence on such a vast, featureless white expanse of ice, floating on the ocean. “I was like: ‘Seriously, you live here? How do you figure it out?’ ” she recalls now. “It’s just phenomenal.” More…