Polar bears really need marine food, and if they are forced off the sea ice and moved inland they might not be able to survive for long, a recent study concluded. A team of scientists sounded the alarm on this matter as more and more polar bears are reported to be hunting on land in areas affected by climate change.
Wildlife biologists with the U.S. Geological Survey monitored a few polar bears who turned inland in search for food since they were no longer able to use the ocean’s frozen surface to hunt. Normally, their diet relies heavily on fat marine mammals, such as seals, and scientists fear they will not get the energetic value they need out of land food.
When reports started coming about polar bears changing their hunting patterns, scientist initially overjoyed. They thought the endangered species was showing that it can adapt to climate changes and might have no trouble surviving. But the latest study conducted by a group of wildlife researchers based in Anchorage, Alaska put things into another perspective.
“There is evidence that some bears are using terrestrial sources in a place such as Hudson Bay, but there’s been no evidence that it’s contributing a significant amount to their energy requirements,” lead author of the study Karyn Rode believes.
Although one group of polar bears, consisting of a handful of specimens, did manage to get enough value out of food like bird eggs or berries, the study suggests they are an exception and changing their diet would not be a solution for polar bears as a species. “Terrestrial foods can’t offer polar bears what they need at a population level,” Rode warned.
The scientific community is currently divided on the matter, as there are some biologists who argue there is enough data to conclude that even larger groups of polar bears can adapt to inland conditions. Robert Rockwell, ecologist with the City College of New York, has been monitoring wildlife in Hudson Bay for almost half of century. He claims to have seen polar bears thrive on goose eggs and caribou calves. “I find it hard to believe they’re going to get nothing out of it,” Rockwell said.
Polar bears have been on the list of threatened species since 2008. There are currently 19 polar bear populations across the planet, massed in four regions. In Hudson Bay, one of the four regions, polar bears showed they can survive without marine food for longer periods of time. But this is owed in part to the fact that Hudson Bay only has seasonal sea ice.
In the other three regions, the polar bears normally stay on sea ice all year long, and their diet is mostly includes fat marine mammals and fish. According to the authors of the study, they are much larger in size than Hudson Bay bears and running around in search of berries or caribou is not feasible.
“This paper establishes in no uncertain terms that polar bears are very unlikely to be able to make a living on land, and that if we don’t save the sea ice, polar bears will indeed be gone,” co-author Steven Amstrup argues.
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