经济学人下载:动物行为 狡猾的冷血动物

Science and technology
科学技术

Animal behaviour
动物行为

Cold-blooded cunning
狡猾的冷血动物

Reptiles are more intelligent than previously thought
爬行动物的智商比人们之前想象的要高

IT IS no compliment to call someone lizard-brained.
如果某人被称为蜥蜴脑，那可不是什么恭维的说话。

The reptilian mind is usually equated in the human one with traits like aggression, dominance and sexual appetite.
爬行动物的头脑通常情况下与人脑相同，也具有侵略、支配和性欲的特性。

That analysis was given currency in the 1960s when Paul MacLean theorised that the human brain has three levels,
这种分析在20世纪60年代得到流行，当时保罗?麦克莱恩从理论上推断人脑具有三个层次，

the most basic—both functionally and literally—being the “reptilian” part, composed of structures called basal ganglia.
人脑最基本的层次—从功能和字面上理解与"爬行"动物相同，它由基底神经节结构组成。

MacLean's analysis is not much believed now by neuroscientists,
麦克莱恩的分析并不为现在的神经学家所认同，

but it has stuck in the popular imagination.
但它始终存在于大众的意识中，

And it has also, subliminally, affected research.
并一直对科学研究有着潜在的影响。

For, until recently, no one had actually thought to ask by experimentation just how intelligent reptiles really are.
直到最近，人们都没有真正想过要通过实验测得爬行动物的智商到底如何。

That omission has just been corrected by Manuel Leal and Brian Powell of Duke University, in North Carolina—and the result is intriguing.
北卡罗莱纳州杜克大学的Manuel Leal和Brian Powell对这一疏忽进行了纠正—其研究结果激发了人们浓厚的兴趣。

In a paper published in Biology Letters Dr Leal and Dr Powell suggest that lizards are at least as intelligent as tits, a group of birds that has been well examined in this respect.
Leal博士和Powell博士发表在生物学快报上的论文表明蜥蜴的智商绝对不比山雀低，研究人员在此方面曾对这组鸟类有过很好的研究。

In their study, the two researchers put a species called Anolis evermanni through a triathlon of cognitive tests of the sort used on tits.
在他们的实验中，两名研究人员让一个叫热带树蜥的动物成功通过一个三项全能的认知测试，这种实验曾用于山雀。

First, the reptiles had to learn how to extract a tasty grub from a container.
首先，爬行动物必须学会如何从容器中获取甜美的食物。

Then, they were taught to associate the grub with a particular colour.
然后教它们如何将食物与一种特定颜色相关联。

Finally, they were taught to dissociate it from that colour and learn that a different colour was the giveaway.
最后教它们将食物与那种颜色脱离联系并学会一种不同颜色代表的是免费美食。

The lizards were able to manage all three tasks with ease—matching the performance of tits in similar tests.
蜥蜴能轻松地完成三项任务—在相同测试中与山雀的表现不分伯仲。

Indeed, in getting at the grubs several of them worked out a form of behaviour never seen in nature,
实际上，在获取食物之时，有几只蜥蜴表现出的行为方式是在自然界中没出现过的，

employing their snouts as levers to lift an obstacle.
它们用鼻子作为手段将障碍物移走。

Having established that lizards are at least as clever as birds at such simple tasks, Dr Leal hopes to go on and explore the evolutionary forces behind lizard intelligence.
在确定了蜥蜴完成简单任务时至少和鸟类同等聪明之后，Leal博士希望将实验进行下去并探索蜥蜴智力背后的进化力量。

He does, however, have a problem—and it is one that might help to explain why, besides phylogenetic prejudice, the lizard mind has not been properly investigated before.
而他的确有一个疑问，这个疑问也许对解释以下问题有所裨益，那就是除去对物种的偏见之外，还有什么原因使得人们之前未展开适当的研究来测定爬行动物的智商。

Tits, being warm-blooded, have to eat a lot and thus have a strong incentive to collaborate with researchers in such experiments.
山雀属于温血动物，它必须吃大量的食物以维持身体的能量，这就使它们具有强烈的动机与研究人员配合进行这种实验。

The average lizard, by contrast, is happy to consume a single grub a day.
相比之下，平均每只蜥蜴一天中只乐意享受一次美食。

It may therefore be some time before the next paper appears on the subject.
因此，下一篇与此主题相关的论文可能需要很长时间才能发表。