26 February 2012 by Julienne du Toit

Why zebras have stripes

Ever wondered about why zebras have stripes? There are many weird and wonderful theories on this. But have you ever considered horseflies?

Up until February 2012, people were pretty vague about why zebras have stripes.

A fair thing to fret at, though. I mean, why would a giraffe have splotches, why would a cheetah and leopard (and baby lions) have spots, and why would a sable have a solid coat?

The theories on zebras ran from the reasonable to the silly. Camouflage was a favourite – it made them blend into the background, apparently. Then there was the theory that each zebra foal identified with the animated pin code that was its mother. Some people also postulated that the stripes made it difficult for predators to pick out individual zebras to prey upon.

Of course, there were ludicrous theories. And it pains me to say that tourists have been mercilessly teased on this subject. Game rangers are certainly not above telling you with a straight face that males are white with black stripes and females are black with white stripes.

Now comes credible news, published in Scientific American, that horseflies caused the stripes. Scientists went to a farm that was infested with horseflies and hung up skins that were dark, light and striped.

Game rangers are certainly not above telling you with a straight face that males are white with black stripes and females are black with white stripes.

Polarising light reflected off solid hides has a certain frequency that attracts these flies, which have painful bites. Striped pelts have a different frequency that doesn’t attract the flies. So horseflies might have provoked this interesting evolution towards stripes.

So when will the dark-coated sable evolve stripes, one wonders. And do splotched giraffe coats also boggle horseflies?

Category: Wildlife

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