How the Zebra Got its Stripes

How the Zebra Got its Stripes

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If there was a ‘Just So’ story for how the zebra got its stripes, Rudyard Kipling certainly would have come up with an amusing and entertaining camouflage explanation. But would he have come up with the explanation that zebra’s stripes stave off blood-sucking insects?

According to a study, published in The Journal of Experimental Biology, horseflies, which deliver nasty bites, carry disease and distract grazing animals from feeding, are attracted to horizontally polarized light because reflections from water are horizontally polarized and aquatic insects use this phenomenon to identify stretches of water where they can mate and lay eggs. However, blood-sucking female horseflies are also guided to victims by linearly polarized light reflected from their hides. Explaining that these insects are more attracted to dark horses than to white horses, the team also points out that developing zebra embryos start out with a dark skin, but go on to develop white stripes before birth. The team wondered whether the zebra’s stripy hide might have evolved to disrupt their attractive dark skins and make them less appealing to voracious bloodsuckers, such as horseflies.