Zebra Stripes Could Be Pest Control

It can be tricky to pin down just why an animal’s coat looks a certain way, and scientists have a few ideas about why zebras evolved to have their trademark black and white stripes — they might act as thermoregulation, or as a unique, confusion-based kind of camouflage, to name just a couple of examples. But one of the more promising, consistent theories — although scientists are still ultimately divided — is that the striped pattern keeps dangerous flies away.

After finding that zebra stripes are more pronounced in areas of Africa with more horseflies and tsetse flies (which can transmit deadly diseases among equines), an evolutionary biologist assembled a team for a new experiment. They observed horses, some dressed up in zebra-striped coats, next to some especially tame zebras, and found that while flies hovered around all of them, they rarely landed on zebras or the striped horses compared to the horses without coats. When flies would approach zebra-striped surfaces, they would behave as if they couldn’t find a good spot to land.