Zebra Black and White Stripes May Not be Used for Camouflage After All

Zebra stripes are not for camouflage. Scientists have found that a zebra's stripes don't act as protection against predators. Instead, it could be that the stripes are for communication.

"The most longstanding hypothesis for zebra striping is crypsis, or camouflaging, but until now the question has always been framed through human eyes," said Amanda Melin, one of the researchers, in a news release. "We, instead, carried out a series of calculations through which we were able to estimate the distances at which lions and spotted hyenas, as well as zebras, can see zebra stripes under daylight, twilight, or during a moonless night."

In this latest study, the researchers found that the stripes simply couldn't be involved in allowing zebras to blend into the background of their environment or in breaking up the outline of the zebra. This is because at the point at which predators can see zebras, they probably already have heard or smelled the zebra prey.

"The results from this new study provide no support at all for the idea that the zebra's stripes provide some type of anti-predator camouflaging effect," said Tim Caro, one of the researchers. "Instead, we reject this long-standing hypothesis that was debated by Charles Darwin and Alfred Russell Wallace."

The researchers found that beyond 164 feet in daylight or 98 feet at twilight, stripes can be seen by humans but are hard to zebra predators to distinguish. The stripes are particularly difficult for all species to distinguish beyond 29 feet. This suggests that stripes don't provide camouflage in woodland areas, where it had earlier been theorized that black stripes mimicked tree trunks. The researchers also found that in open, treeless habitats, lions could see the outline of striped zebras just as easily as similar-sized prey with fairly solid-colored hides.

The findings reveal that stripes are not for camouflage. Instead, they're possibly used socially by zebras.

The findings are published in the journal PLOS One.

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