科学美国人60秒 SSS Climate Change Fires Up Polar Bear Treadmill（在线收听）

Climate Change Fires Up Polar Bear Treadmill

气候变化害苦了北极熊

Polar Bears spend most of their time roaming the sea ice in search of seals. And seals spend most of their time underneath that ice, avoiding the top predator. But climate change is giving polar bears additional challenges in their searches for food.

北极熊大部分时间都在海冰上漫游，寻找海豹。而海豹大部分时间则都呆在冰层下，避开冰层上的捕食者。但气候变化给北极熊觅食带来了额外的挑战。

“Sea ice is now drifting faster.” George Durner is a research zoologist with the United States Geological Survey Polar Bear Research Program. He and colleagues compared sea ice conditions from 1987-1998 with those from 1999 to 2013.

“海冰现在漂得更快了。” 乔治·德纳——美国地质调查局北极熊研究项目组的一名研究动物学家。他和他的同事们将1987年至1998年的海冰状况与1999年至2013年的海冰状况进行了对比。

\“And what we found was ice drift at the locations used by polar bears increased 30% in the Beaufort sea and 37% in the Chukchi sea.” That’s a problem because polar bears are homebodies—they prefer to stay in a specific range.

“我们发现，在波弗特海地区北极熊使用的漂冰增长了30%，而在楚科奇海地区则增长了37%。”这是一个问题，因为北极熊是居家型物种——它们喜欢呆在一个特定的范围内。

“Throughout their range, they seem to have a sense of place. And … here we have a situation where the general pattern of ice drift is westward, so to remain in your traditional range, it means you have to constantly be walking eastward to compensate for that westward drift.”

“在它们的生活范围内，它们似乎会有一种归属感。然而……这里面临的情况是，漂冰一般是向西漂流的模式，所以留在它们本来生活的范围内，就意味着它们必须不断的向东行走，以弥补漂冰的向西运动。”

The result: a large-scale polar bear treadmill. And all that walking requires extra fuel. On average, a single bear eats between 31 and 33 seals per year. But the metabolic consequence of the treadmill effect means they have to eat on average one to three more. The study is in the journal Global Change Biology.

结果就是：大规模的北极熊徒步迁徙。而这种徒步迁徙需要额外的能量。平均来说，一只北极熊每年会吃掉31到33只海豹。但徒步迁徙带来的代谢后果意味着它们平均要多吃一到三只海豹。这项研究发表在《全球变化生物学》杂志上。

And not only is the ice drifting faster—it’s also melting more, giving the bears less of the platform they use to pursue their prey. So they need more seals but have a tougher time tracking them. All of which puts polar bears on a slippery slope.

然而海冰不仅漂流得更快了，它融化的也更多了。这使得北极熊可用的用来追捕猎物的平台变得更少了。因此，北极熊需要捕猎更多的海豹，但追踪海豹却变得更加困难了。所有这些都使北极熊的境地越来越糟糕。