英语听力文摘 English Digest 539、为什么斑马身上有条纹？

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　　For many animals, camouflage¹ is an important part of survival. A leopard’s spotted² coat and a polar bear’s white fur help them blend into their respective environments. But a zebra’s bold stripes can’t help to disguise it in its natural habitat, the open plains of Africa.or can they?

 

　　Why Zebras Have Stripes? On this moment of science.

 

　　The zebra’s bold markings can also help to conceal³ it. In 1844, naturalist⁴ Francis Galton pointed⁵ 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 predator⁶ sees a zebra.

 

　　The zebra’s bold markings draw the viewer’s 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 herd⁷, 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 deer’s 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. When mating, adult zebras use stripes to recognize members of their own species.

 

　　As one nineteenth century breeder discovered, a female zebra will object vehemently⁹ to mating with a male ass⁸. But when the rejected suitor was disguised with hand-painted stripes, the female zebra happily accepted him.

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