Summertime dips in activity and body temperature may not be enough to protect bears from challenges of climate change
Polar bears’ normal summertime energy-saver mode is called “walking hibernation.” But it may not be drastic enough to compensate for lengthening warm seasons — and accompanying food shortages — as climate changes, researchers say.
What happens to summertime bears is more like fasting than like winter hibernation, says ecologist John Whiteman of the University of Wyoming in Laramie.
Biologists suspected a general slowdown of the bears’ metabolism when the springtime seal-hunting bonanza ends as sea ice recedes, but measurements have been sparse. Using data-collecting collars and implants, Whiteman and colleagues showed that polar bears following the receding ice out to sea, as well as the left-behinds onshore, were less active in summer.