Polar Bear Metabolism Cannot Cope With Ice Loss

Polar bears' metabolism does not slow very much during the summer months when sea ice melts and food becomes scarce. With the Arctic warming faster than the global average, the finding does not bode well for the bears, who use the ice as a hunting ground. According to a study by wildlife ecologist Merav Ben-David, the Arctic ice is melting earlier each summer and freezing later each winter, limiting the animals' chances to catch seals. With no way to save energy, polar bears are unlikely to survive the continued sea-ice loss caused by rising temperatures. The research suggests that the bears do not use a strategy known as walking hibernation — a state of lowered activity and slowed metabolism—to survive summer fasts as some had suspected. Instead, they show a smaller decrease in their metabolic rate, similar to that seen in any mammal with a restricted diet.