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为什么斑马身上有条纹?

2021-04-19

阅读与作文(英语初中版) 2021年3期
关键词:白点斑纹条纹

For many animals, camouflage is an important part of survival. A leopards spotted coat and a polar bears white fur help them blend into their respective environments. But a zebras bold stripes cant help to disguise it in its natural habitat, the open plains.

The zebras bold markings can also help to conceal it. In 1844, naturalist Francis Galton pointed out that stripes can help disguise zebras in the dim, grayish light of an African night. Fifty years later, an artist named Abbot Thayer suggested that stripes could help actually change the way a predator sees a zebra.

The zebras bold markings draw the viewers attention to the stripes themselves, not the shape of the animal. So when a predator looks at a zebra, it sees stripes first, and then the zebra. This split second of recognition gives the fleet-footed zebra a chance to escape.

To other zebras in the herd, the flash of stripes they see when one zebra starts to flee from an approaching lion is a “follow me” signal. Like the white flash of a deers tail, it alerts the entire herd to danger. The approaching lion, on the other hand, often loses his initial target in the confusing mass of moving stripes.

Stripes also allow young zebras in search of a meal to identify their mothers. And adult zebras use stripes to recognize members of their own species.

對于很多动物来说,伪装是生存的重要部分。猎豹的花斑和北极熊的白毛都能帮助它们融入各自的生存环境当中。而斑马醒目的条纹却不能帮助它们融合到自己所生活的开阔平原当中。

斑马醒目的斑纹也可以把自己隐藏起来。1844年,自然学家Francis Galton指出,这些条纹可以帮助斑马在非洲夜晚那灰暗的微光下伪装自己。五十年后,一位名叫Abbot Thayer的艺术家提出这些条纹可能会改变猎食者看到的斑马形象。

斑马醒目的斑纹把观察者的注意力吸引到斑纹本身,而不是动物的轮廓。因此,当猎食动物看斑马时,它先注意到的是斑纹,然后才是斑马。这不到一秒的时间给了动作很快的斑马逃脱的机会。

当一匹斑马开始逃避正在靠近的狮子时,斑马群中的其他斑马看到的闪动条纹对它们来说意味着“跟我来”的信号。跟鹿尾后闪动的白点一样,这对整群动物来说是危险警报。而另一方面,对正在靠近的狮子来说,在一团令人眼花缭乱的移动斑纹之中经常会找不到最初定位的目标。

斑纹也可以帮助正在找食的小斑马辨别自己的母亲。成年斑马则可以通过斑纹来识别自己的同类。

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