Some animals use tools to get food. One kind of crow5 eats insects6 that live in the bark7 of trees. The crows come from New Caledonia（新喀里多尼亞島）， a group of islands east of Australia. These birds use sticks to dig food out of the bark. Sometimes the crows form straight sticks into hooks8. Now scientists know why. The crows can get food much faster using hooks！ That is very efficient. Most wild animals have to work hard to get food. Animals that can get food easily may live longer. Their babies are often strong and healthy.

有些動(dòng)物使用工具為自己獲取食物。有一種烏鴉吃樹(shù)皮上的昆蟲(chóng)。這種來(lái)自澳大利亞?wèn)|部新喀里多尼亞島的烏鴉們，不僅能使用樹(shù)枝挖出樹(shù)皮中的昆蟲(chóng)，還能將筆直的樹(shù)枝打磨成鉤子形狀，用它來(lái)釣取食物?？茖W(xué)家們解釋說(shuō)，烏鴉使用這種鉤狀工具，對(duì)其幫助很大，效率大大提升。在自然界，大多數(shù)野生動(dòng)物不容易獲取食物。此種能力往往決定著動(dòng)物的壽命與幼崽的健康程度。

Did you know？

A crow named Betty surprised scientists in 2002. She made a hook out of a piece of wire and used it to get food. Some wild crows know how to make hooks out of sticks. But Betty did not live with wild crows. No one showed her how to make hooks. She came up with this idea on her own！

研究小背景

2002年，一只名叫貝蒂的烏鴉驚艷了科學(xué)家。她將一根金屬絲彎成鉤子形狀，并用它取出了食物。盡管野生烏鴉能夠用樹(shù)枝做成覓食工具，但貝蒂并不是野生的，更沒(méi)有其他烏鴉教會(huì)她這一本領(lǐng)。這全部都是貝蒂自己的“原創(chuàng)”！