A recent study brings more grim news for polar bears and the people striving to save them from extinction. University of Wyoming researchers found that a theory released in the 1980s stating that the furry beasts can survive the scarce food conditions in summertime by entering a “walking hibernation state” is plain wrong.
Polar bears in the Arctic need the sea ice to hunt for seals, but as global warming advances the sea ice shrinks leaving the bears certain candidates for starvation death, researchers argue. And the situation can get a lot worse during summertime.
But some studies led in the early ’80s concluded that polar bears have a special ability of surviving with no food for prolonged periods of time. Those studies claimed that some markers in the animal’s blood samples revealed they could go into a “walking hibernation” state until they were able to find new sources of food.
Walking hibernation means that the animals are wide awake but their metabolic processes are significantly reduced so they can save as much energy as possible. Back in the 1980s, scientists argued that this type of adaptation can help the creatures survive without food especially in summer when the sea ice is reduced and hunting is so difficult.
The scientific community bought the theory and believed in it for more than three decades. But a paper published July 16 in the journal Science challenges the walking hibernation theory with evidence gathered from more than two dozens specimens.
The new study’s authors tranquilized and captured the bears, and equipped them with GPS and body temperature trackers. During the research, scientists monitored both shore and ice bears.
The team said that they wanted to test whether the walking hibernation theory was correct. If indeed it had been valid, the bears would have lowered their activity and body heat levels to the ones detected during their genuine hibernation, researchers noted.
Merav Ben-David, lead author of the study and wildlife ecology expert at the University of Wyoming, said that his team didn’t see any significant metabolic changes in the bears to confirm the theory. Their body temperature was supposed to drop to 35 degrees C and stay like that over the entire “hibernation” time, but it didn’t.
Scientists observed only moderate metabolic changes that are perfectly natural for polar bears and any animal that tries to survive on low food.
“If you went into an extended fast, your body temperature would decline too. It’s a normal mammalian response to fasting and losing […] losing weight,”
Image Source: Picslist