Ever wondered why Zebras have stripes? Fact 28

Well you better now if you haven't, as there is a fascinating story waiting for you... Researchers from the University of California at Davis went into figuring out the answer to this question with key data - that certain flies avoid Black and White surfaces. Could that be the very same reason for the Zebras? To tackle that question, the researchers examined the distribution of zebras and the locations of the best breeding grounds for the stripe-averse flies. Sure enough, they found that they overlap. The same was true for other animals in the horse family that had stripes on various parts of their bodies.

“I was amazed by our results,” said lead author Tim Caro, a wildlife biologist at UC-Davis. “Again and again, there was greater striping on areas of the body in those parts of the world where there was more annoyance from biting flies.”

The study published on the 1st of April, 2014, Nature Communications,  builds on a 2012 study by Swedish researchers of Lund University that used horse models painted black and white to test whether flies would avoid stripes.

But why are stripes anathema to flies? It turns out that flies find stretches of water to mate and lay their eggs in by looking for the horizontally polarized light it reflects. Zebra stripes, however, are vertical and reflect polarized light differently, which makes them unappealing to horseflies. Unlike other African mammals, zebras have shorter hair that flies may be able to penetrate more easily to bite into the skin.

Researchers have yet to test their bug repellent theory in the wild, however. Zebras have striped insect armor, but they also emit odors that may attract flies, potentially canceling out the benefits of their striped coats.