The surprising truth about bird brains, monkey minds, and more

Scrub jays can trick you, researchers say. Monkeys kick themselves for mistakes in judgment. And at least one parrot figured out something close to the mathematical concept of zero.

Animals can be remarkably devoted-as the stories on these pages prove. What's less obvious is how smart they are. In study after study over the past decade, they've shown abilities previously thought to exist only in humans.

Take the scrub jays. A few years ago, Cambridge University professor Nicky Clayton, PhD, found that these birds can be surprisingly devious, remembering not only what foods they've hidden but where, how long ago, and whether anyone else might have noticed. "If another bird was watching, they'd wait until that bird was gone and then move the food," Clayton says.

Even more interesting, not all jays protected their food that way-only those that had previously raided other birds' stores. "It takes a thief to know a thief," says Clayton. Another recent experiment hints that monkeys experience regret when they make the wrong choice and miss out on a treat: Researchers say brain scans suggest the animals were having "coulda, woulda, shoulda" thoughts.

"I knew monkeys were smart, but I didn't think they were that smart," says Michael Platt, PhD, the Duke University neurobiologist who led the study.

But perhaps no animal has done more to upend conventional notions than Alex, an African gray parrot. A 30-year research subject for scientist Irene Pepperberg, PhD, Alex whittled away at the belief that parrots were simple mimics. He was constantly being tested; when he tired of it, he would tell Pepperberg, "Wanna go back"-to his cage. If the request annoyed her, Alex would say, "Sorry." The parrot toyed with her relentlessly, and one afternoon, he showed an apparent grasp of something only humans and a few apes had been known to understand: the notion of zero.

Pepperberg had a tray of different-colored balls; she wanted Alex to count each group. Using their shorthand, she asked, "What color six? What color two?" Bored, Alex threw the balls on the floor instead. Then, finally, he said, "Five." And repeated it: "Five. Five." There were no five of anything on the tray. So Pepperberg asked, "Okay, smarty, what color five?"

Alex said, "None."

Not only had the bird figured out an abstract mathematical concept, he had manipulated Pepperberg into asking the question so he could prove it. "I nearly dropped the tray," she says.

关于鸟类大脑，猴子思维以及更多的惊人真相

研究者发现，灌木丛里的鸟儿也能把你骗到。猴子会因为自己判断失误而自我惩罚。至少已经有一只鹦鹉能够理解一些与"0"相近的数学概念。

动物可以非常忠诚--正如这些网页上的故事所证实的那样。但是它们的聪明伶俐就不是那么显而易见的了。过去十年间，一项又一项研究表明，动物表现出过去认为只有人类才具有的能力。

这里以灌木丛鸟作为例子。几年以前，哥伦比亚大学教授，Nicky Clayton发现这些鸟儿惊人的狡猾，它们不仅能记住自己藏了什么食物，而且记得何时，多久以前，是否会被其它动物发现。"如果被其它鸟儿看着，它们会耐心等待，直到那鸟儿飞走它们才会搬动食物。" Clayton 说。

更为有趣的是，不是所有的鸟都用这种方法保护它们的食物--只有那些曾经偷吃其它鸟的食物的鸟才会这样。"最了解小偷的人就是小偷。"Clayton说。另一个最新的实验则启示我们，猴子在因为自己错误的选择而错失食物后会感到后悔：研究者声称，脑扫描表明猴子们有"本可以，本来会，本应该"的想法。

"我知道猴子聪明，但我没想到它们是如此聪明。" 杜克大学的神经生物学教授Michael Platt说，他是上述研究的负责人。

但是，或许没有其它动物比Alex,一只非洲灰鹦鹉，更加颠覆了传统观念。对于科学家Irene Pepperberg博士来说，Alex,这只30岁的实验对象削弱了"鹦鹉只是简单的模仿生物"这一观念。Alex不断接受实验，当它厌倦时，它会告诉 Pepperberg博士："想要回去"--回到它的笼子里。如果实验要求令它不高兴了，Alex会说："对不起。"这只鹦鹉无所顾忌地与博士玩耍。一天下午，Alex表现出只有人类和少数猩猩才拥有的理解力：0的概念。

Pepperberg博士拿来一个盛着不同颜色的球的盘子。她要求 Alex数出每种颜色的球有多少个。Pepperberg博士用很短的句子提问："什么颜色有6个？什么颜色有2个？"Alex把球丢起来扔到地上，感到厌烦。最后，它说："5."之后一再重复："5,5."盘子上并没有5个同样颜色的球。于是Pepperberg博士问到："好的，你很聪明，什么颜色有5个？"

Alex 回答说："没有。"

Alex不仅理解了抽象的数学概念，而且还引导Pepperberg博士问出问题，好让它来解答。 "我几乎把盘子摔在了地上。" Pepperberg博士说。