英語(yǔ)聽(tīng)力文摘 動(dòng)物也愛(ài)散步？

When you’ve been to the zoo have you noticed how some of the animals pace around a lot?

Scientists think the problem might be that the animals miss the freedom to roam. That make sense. After all, a polar bear’s natural range is about the size of South Carolina. Right. And the typical zoo habitat is about one millionth of that.

Researchers in Oxford studied the pacing behavior of thirty-five captive species using data from over one thousand scientific articles published since the 1960s. When they analyzed this data–which represented more than five hundred zoos worldwide–they determined that the deciding factor for pacing was range size.

That also explains why stay-close-to-home species like snow leopards tend to thrive in zoos. So what happens now?

Well, one option is for zoos to build larger, more varied 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 captivity.

The problem is that this is a double-edged sword: these animals’ natural habitats are increasingly threatened as well.

你去動(dòng)物園的時(shí)候有沒(méi)有注意到，有些動(dòng)物喜歡到處走動(dòng)?

科學(xué)家認(rèn)為這可能是因?yàn)樗鼈儽粍儕Z了散步的自由。有道理。一只北極熊自然分布范圍為整個(gè)南卡羅萊納州。對(duì)。而一般動(dòng)物園的大小只是南卡羅萊納州百萬(wàn)分之一。

牛津的研究人員調(diào)查了從20世紀(jì)60年代發(fā)表了一千多篇科學(xué)論文里的數(shù)據(jù)，是關(guān)于35個(gè)圈養(yǎng)物種的散步習(xí)性。他們對(duì)這些數(shù)據(jù)研究后發(fā)現(xiàn)：這些數(shù)據(jù)代表了世界上500多個(gè)動(dòng)物園，他們因此確定散步習(xí)性的決定因素是動(dòng)物的分布范圍。

那就可以解釋：為什么留守家園附近的物種像雪豹在動(dòng)物園很多了?，F(xiàn)在呢?

一個(gè)選擇就是把動(dòng)物園建大一點(diǎn)，更多樣化和定期變換圍墻促進(jìn)動(dòng)物們散步。但還有一個(gè)更好的選擇就是將那些像北極熊的動(dòng)物走出動(dòng)物園，多關(guān)注那些能夠圈養(yǎng)的動(dòng)物。

問(wèn)題在于這是把雙刃劍：這些動(dòng)物的自然習(xí)性會(huì)受到很大的影響。