Polar Bears Are Starving Because of Global Warming, Melting Sea Ice, Study Shows - 0 views
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Because of melting sea ice, it is likely that more polar bears will soon starve, warns a new study that discovered the large carnivores need to eat 60 percent more than anyone had realized.
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Polar bears rely almost exclusively on a calorie-loaded diet of seals. To minimize their energy consumption the bears still-hunt, waiting for hours by seals’ cone-shaped breathing holes in the sea ice. When a seal surfaces to breathe the bear stands on its hind legs and smacks it on the head with both of its front paws to stun it. Then the bear bites it on the neck and drags it onto the ice.
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Climate change is heating up the Arctic faster than anywhere else, and sea ice is shrinking 14 percent per decade. Even today, in the middle of the bitter cold Arctic winter, satellites show there is about 770,000 square miles less sea ice than the 1981 to 2010 median (That's an area larger than Alaska and California combined). In the late spring, the ice is breaking up sooner and forming later in the fall, forcing bears to burn huge amounts of energy walking or swimming long distances to get to any remaining ice. Or they stay on land longer, spending the summer and, increasingly, the fall fasting, living off their fat from the seals they caught in the spring.
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The data showed the bears were active about 35 percent of the time and resting for the remainder, yet they burned through 12,325 calories a day, much of it from their body reserves. That’s about 60 percent more than previous studies had estimated. The videos revealed that four of the females weren’t able to catch a single seal. Measurements showed those animals lost 10 percent or more of their body mass.
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More swimming could lead to smaller bears, reduced reproduction rates, and even increased risk of death
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The farther the bears have to travel to get on the ice to hunt the more weight they lose. Eventually they start losing muscle, hurting their chances of hunting success, which can lead to a downward spiral. Bears are also doing a lot more swimming as the sea ice declines, said Derocher.
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“As the sea ice melts earlier and earlier, polar bears are forced to swim more and more, to reach seal populations,”
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Polar bears are considered endangered in the U.S. and are listed as “vulnerable” by the IUCN, because their sea ice habitat is under threat from climate change.
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There’s no doubt that as the sea ice declines more and more bears are going to starve to death, said Amstrup. “I don’t know if that poor bear in that video was starving. I do know that the only solution for the long-term survival of the polar bear is to address climate change.”