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Polar bear adapts to climate change by altering its diet patterns， study suggests北极熊是北极的最高级食肉动物，也是世界上最大的四足食肉动物。与其他熊类不同，它们是海洋哺乳动物，已适应了在地球上最极端的环境——北冰洋，繁衍生息。北极熊是现今存在的六个熊类中最新的一种，它们起源于15万年前，当时西伯利亚和阿拉斯加州的灰熊生活在北冰洋或周围地区。阿尔伯塔大学生物学教授兼国际自然保护联盟的北极熊专家组主席安德鲁·德洛契尔说，由于以海冰为食的熊类没有留下什么遗体（尸体可能已沉降到大洋底部），高等捕食者比其他低营养级的物种要少得多，加上北极熊的化石记录很难获得。研究表明，北极熊通过改变其饮食能够从冰层融化中生存下来，并适应新气候。人们通常认为北极熊是最容易受全球变暖现象影响的动物，但《国际财经时报》称，新研究表明，一旦北极熊无法获取它们喜爱的食物时，它们就会改变其饮食。研究人员发现，尽管海豹是它们的最爱，如果一时间寻觅不得，它们也会以驯鹿、雪雁、草籽和浆果等为食。该项研究的研究人员和共同作者琳达·戈莫扎诺（Linda Gormezano）说，“研究表明，北极熊的觅食策略非常灵活。”而这并未改变北极熊易受气候影响的事实，但的确表明，北极熊的饮食比我们之前认为的要灵活许多。《头条日报》和《环球新闻》称，尽管这一灵活性着实让人吃惊，也对北极熊大有裨益，但改变饮食很有可能无法完全帮助北极熊摆脱气候变化的厄运。由于全球变暖，不仅人口在减少，而且北极熊的食物也变得短缺。Polar bears are the Arctic’s apex predator， and the largest four-legged predator in the world. Unlike other bears， they are marine mammals， and have adapted to thrive in one of our planet's most extreme environments， the Arctic Ocean.Polar bears are the newest of the six bear species that exist today， arising about 150，000 years ago， when grizzly bears living in Siberia and Alaska adapted to living in and around the Arctic Ocean. Because bears that live on sea ice don't leave many remains （carcasses have a tendency to sink to the bottom of the ocean）， and top predators are much less abundant than species at lower trophic levels， piecing together a polar bear fossil record is tough， according to Dr. Andrew Derocher， professor of biology at University of Alberta， and Chair of the IUCN’s Polar Bear Specialist Group.Polar bears have shown that they will be able to survive the ice melting by changing their diet and adapting to the new climate.Polar bears are often thought as the animal that is most affected by global warming， but new research has shown that when the food they prefer is not available， the bears are willing to change their diet， according to the International Business Times. Though they prefer seal， in times when they are not available researchers have found they will eat caribou， snow geese， grass seed and berries."What our results suggest is that polar bears have flexible foraging strategies，" Linda Gormezano， and a co-author of the study said. This does not change the fact that polar bears are obviously affected by the climate， but it does show that polar bears are much more flexible in their diet than previously thought.Though this flexibility is certainly surprising and will have advantages for the bears， it is unlikely that this diet change will completely save the polar bears from the changing climate， according to Headlines and Global News. Global warming is still causing population decrease as well as a scarcity of food for polar bears. （Source： Ecology news， monitoring， celebritycafe）