Polar Bears Forced To Hunt On Land For New Prey As Arctic Ice Shrinks
Faced with Arctic ice that melts earlier and freezes later every year, polar bears are switching up their diets. In the Hudson Bay, polar bears are increasingly consuming plants and land-based prey, as their favorite foods--seals and marine animals--are unavailable to them as ice melts. The polar bears' shifting diets are detailed in a series of studies written by scientists from the American Museum of Natural History.
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"There is little doubt that polar bears are very susceptible as global climate change continues to drastically alter the landscape of the northern polar regions," said Robert Rockwell, a research associate in the museum's Department of Ornithology. "But we're finding that they might be more resilient than is commonly thought."
Polar bears hang around gaps in sea ice waiting for seals to prey on. When ice melts, polar bears move to land to get their food, and now, with shrinking Arctic ice, polar bears are spending more time on land than ever before. They're shifting to land-based foods to make up for having fewer seals in their diet. Snow geese, eggs and caribou are now all on the menu, which also includes vegetarian options like mushrooms and berries.
In one study, the scientists videotaped polar bears in the Hudson Bay, while revealed them to be killing and eating snow geese. Another study looked at remnants of snow geese in polar bear scat, from an analysis done from 1968 to 1969, when drastic climate change had yet to occur. The scientists found fewer snow geese remnants in the 1960s scat as compared to that of modern times. Modern scat also contained caribou and goose eggs, which wasn't found in the older scat.
The good news from these studies is that polar bears are adapting to climate change. The bad news is that because eating blubbery seals fattens up polar bears, the fewer fatty seals polar bears can consume, the less fat they can put on to see them through the winter. Turning to new foods, as the polar bears are doing, is helping them to survive, but in the long run it might be enough, the scientists believe. "We can't say for sure that the amount of calories in this food will compensate for lost seal hunting opportunities," said Gormezano.
"Some of these things could buy some individual bears a bit more time," said Steven C. Amstrup, a researcher with Polar Bears International, who wasn't involved in the studies. "But the bottom line is that there is no evidence that any alternate foods will benefit polar bears at the population level."
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