乌鸦自制钩状工具

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（新喀里多尼亚岛）， 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.

有些动物使用工具为自己获取食物。有一种乌鸦吃树皮上的昆虫。这种来自澳大利亚东部新喀里多尼亚岛的乌鸦们，不仅能使用树枝挖出树皮中的昆虫，还能将笔直的树枝打磨成钩子形状，用它来钓取食物。科学家们解释说，乌鸦使用这种钩状工具，对其帮助很大，效率大大提升。在自然界，大多数野生动物不容易获取食物。此种能力往往决定着动物的寿命与幼崽的健康程度。

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，一只名叫贝蒂的乌鸦惊艳了科学家。她将一根金属丝弯成钩子形状，并用它取出了食物。尽管野生乌鸦能够用树枝做成觅食工具，但贝蒂并不是野生的，更没有其他乌鸦教会她这一本领。这全部都是贝蒂自己的“原創”！