Already facing warmer summers, diminishing habitat and possible pollution-related health problems, the polar bear may not be physiologically equipped to deal with a warming climate, experts say.
With these heightened risk factors, the snow-dwelling bruin is not going into a "hibernation" mode in the hotter months when food is harder for them to come by, according to a study in the journal Science.
Polar bears were thought to enter a hibernation-like state in the summers because "such a strategy could partially compensate for the loss of on-ice foraging opportunities caused by climate change," researchers said in the study published in July.
"That means they use more energy than we thought they were, at the same time they do not acquire any," said Merav Ben-David, professor of zoology and physiology at the University of Wyoming who led the study on polar bear metabolism.
"They are sensitive to the lengthening of the ice melt period in summer," Ben-David told CNBC. In other words, the already-threatened polar bear won't be able to hibernate in order to avert starvation.