英语听力文摘 English Digest 406、动物真的会数数？（在线收听）

Can Animals Count?
动物会数数？

Can animals count? People count easily, from the time we are little kids and learn our one-two-threes. But what about other species? Careful observations in the wild support the idea that some can.

The American coot is a duck-like North American bird. Sometimes a coot will try and sneak one of its eggs into a neighbor’s nest. Some coots recognize the deception, and roll the stranger’s egg out again. Others don’t catch on, and raise the stranger’s egg as their own.

Researcher Bruce Lyon at the University of California, Santa Cruz, and his team observed a series of coot nests for four seasons, noting which birds could spot a stranger’s eggs and which couldn’t. Then they compared how many eggs each kind laid.

Their finding? The coots that couldn’t tell when a stranger’s egg had been stuck into their nest laid that many fewer of their own–sneak one in, the coot lays one fewer.

Sneak two in, the coot lays two fewer. Coots that successfully spotted intruders knocked them out again and then laid the same number they normally would.

If the number of eggs laid were independent of how many the coot sees in its nest, coots that allow a stranger’s egg should wind up with one egg extra. But they don’t.

Lyon argues that, along with egg recognition, the coots must therefore be doing some version of “I see I have nine eggs here–time to stop laying now.” And that means coots count.

Other researchers aren’t convinced. But though the debate goes on, the case for animal counting just got stronger…by the weight of one coot.

动物会数数吗？对于人来说，数数很简单。当我们还是小孩的时候就学会数数了。但是其它生物呢？通过在自然环境下的一些仔细观察发现有的动物能数数。

美洲白骨顶是一种鸟，它们生活在北美并且长得像野鸭。有时白骨顶尝试把自己的蛋偷偷放到相邻巢穴中。有的白骨顶能识破诡计，把这个不明来路的蛋挑出来。其它白骨顶根本认不出，就把它当作自己的后代抚养长大。

研究人员，加利福利亚大学的布里斯里昂，在圣克鲁斯和他的团队观察了很多的白骨顶巢，并且是在不同 的季节。他们记录下了哪些鸟能认出陌生的鸟蛋，哪些不能认出。然后他们比较了这些鸟各生了多少蛋。

结果呢？发现那些不能认出陌生蛋的鸟，它们巢穴里的陌生蛋越来越多，而自己的蛋越来越少。

多出两个陌生蛋，它们就会少生两个蛋。而那些认出闯入者的鸟则会将其赶走，然后生产通常相同数量的蛋。

如果生产蛋的数量与巢里蛋的数量是独立的，那么白骨顶就会算上陌生蛋，不再生蛋。可是他们它们不会。

里昂认为，有识别蛋能力，所以白骨顶可能在想“已经有了九个蛋，可以停止产蛋了”。那就意味着它们能数数。

其他研究人员并不相信这一理论。虽然争论还在继续，但动物会数数的事例越来越靠谱，因为一只白骨顶。