If you thought the purpose of the zebra’s stripes was to camouflage them from the dangers of the bush, science has proved you wrong!
In a new study, researchers from the University of Calgary and UCDavis have discovered that the stripes in fact have nothing to do with protecting the creatures from predators or helping them blend into surroundings, because by the time predators have actually identified the stripes, its distinctive scent or sound would already have made the hunter aware of the creature’s presence.
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In previous studies, UC Davis professor of wildlife biology, Tim Caro and his team of scientists have provided evidence to suggest the zebra’s stripes are an evolutionary advantage as they deter biting flies, which are natural pests of zebras.
“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, assistant professor of biological anthropology at the University of Calgary and lead author of the study.
Scientists can’t agree on whether a zebra’s stripes keep the flies away, regulate body temperature, or act as camoflage.
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“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,” she adds.
Scientists found that beyond 50 metres (164ft) in daylight or 30 metres (98ft) at twilight, when most predators hunt, stripes are distinguishable for humans but are hard to spot among the zebra’s main predators. They also found that on moonless nights, all species find it difficult to see beyond 9 metres (29ft); this suggests that stripes do not provide camouflage within wooded areas, as it was originally thought that the black stripes imitate tree trunks while the white blends in with shafts of light through the trees.
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In open, treeless environments, researchers found that lions could identify zebra just as easily as other prey, discrediting the idea that the striping disrupts the visible outline of the creature on the plains, where the zebra is known to spend the majority of its time.
In addition to disproving the camouflage hypothesis, researchers are yet to find any proof that the stripes serve a social purpose by allowing fellow zebras to recognise each other at a distance. The scientists note that many other species are able to recognise their own kind from far away despite not wearing a distinctive pattern on their fur.
“no support at all for idea that zebra’s stripes provide anti-predator camouflaging effect” https://t.co/nl08evmJ2D
— Wilmie Burton (@wilemientjie) January 26, 2016
“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 Caro. “Instead, we reject this long-standing hypothesis that was debated by Charles Darwin and Alfred Russell Wallace.”
Findings from the study are published in the scientific journal, PLOS ONE.
Additional reporting by R&D Mag.
Image via Shutterstock.