Unlike other mammals who enjoy feasts during summer months, summer heralds famine for polar bears living in the Arctic. Rather than going into a state of hibernation to conserve energy, polar bears go into starvation, researchers have found.
While it has been known that polar bears are endangered due to their melting habitat, scientists have learned that their plight is even worse than previously thought.
Scientists used to believe that polar bears entered a state of “walking hibernation” when they were deprived of their usual diet of seals. To test the theory, scientists surgically inserted tracking devices in more than two dozen bears in the Beaufort sea, which is north of Alaska.
The implants tracked the bears’ movements and physiological indicators. It turns out polar bear aren’t like hibernating bears. Instead, the polar bears kept moving and starved when food was scarce.
The results of the study were published Friday in the journal Science.
“Their metabolism is very much like a typical food-limited mammal rather than a hibernating bear,” said lead researcher John Whiteman from the University of Wyoming to the BBC. “If you or I were to be food-limited for weeks on end we would look like the bears’ data.”
These large carnivores hunt on the Arctic ice and when the ice disappears, so does their ability to hunt seals, their main source of food.
Research zoologist George Durner at the U.S. Geological Survey told the Standard Daily, polar bears are living in a part of the Arctic that is always subject to extensive sea ice loss. Either the polar bears adapt to land situations or be forced to hunt under ice that can go as deep as 5,000 meters or more.
Polar bears cannot hunt for seals in waters deeper than 5,000 meters because seals are better divers, more agile, and can stay under water longer than the bears.
One glimmer of good news was discovered about polar bear physiology. Researchers found that the bears have an incredible adaptation to swimming in cold water. The bears’ outer body cools and this reduction in energy use allows the vital inner organs to remain warm.
These bears are physically capable of taking marathon-like swims from shore to reach an ice floe that may yield food. The researchers related a story of how a female bear had survived a nine-day, 400-mile swim from shore to ice. The swim and lack of food took a toll of her body, having lost 22 percent of her body mass.
These findings are bad news for the polar bears who face starvation in spring and summer. As the sea ice continues to melt more, these animals are in grave danger of starving to death.
