【英语时差8,16】天生爱游荡

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When you've been to the zoo have you noticed how some of the animals pace around a lot? In this Moment of Science Don and Yaël discuss one explanation for this behavior.   

D: Yaël, I went to the zoo yesterday, and boy, the polar bear just kept pacing in circles, and don't even get me started about the lions. I guess they must really miss hunting, huh?

Y: You know, Don, that's what scientists used to think too, and so zoos worked hard to compensate¹ for this by focusing on stimulating² hunting behavior. But now scientists think the problem might be that the animals miss the freedom to roam.

D: That makes sense. After all, a polar bear's natural range is about the size of South Carolina.

Y: Right--and the typical zoo habitat is about one millionth of that.

D: No wonder some animals spend about a quarter of their time pacing. But how did scientists figure out that this was the problem?

Y: Well, researchers at Oxford³ studied the pacing behavior of thirty-five captive species using data from the over one thousand scientific articles published since the 1960s. And when they analyzed⁴ this data--which represented more than five hundred zoos worldwide--they determined⁵ that the deciding factor for pacing was range size. That also explains why stay-close-to-home species like snow leopards⁶ tend to thrive in zoos.

D: So what happens now?

Y: Well, one option is for zoos to build larger, more varied⁷ habitats, and switch enclosures periodically to simulate roaming. But a better option might be to phase animals like polar bears out of zoos, and focus instead on those animals that do well in captivity⁸. The problem is that this is a double-edged sword: these animals' natural habitats are increasingly threatened as well.

D: Depressing.

Y: No kidding.  

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