Scientists finally figure out why zebras have stripes

How the zebra got its stripes has been puzzling scientists for centuries, but new research suggests those bands of black and white are designed to deter disease-carrying flies.

Camouflage, cooling, or an optical illusion to confuse predators. All of these have been theories explaining why stripes adorn zebras, but scientists, including Charles Darwin, just couldn’t settle on a solid hypothesis. Compare zebras to the other grazing animals and it doesn’t add up. If its stripes are for camouflage, why do they spend all day in the open plains, where you will find no black and white grass?

The latest study, from biologists at the University of California, may have solved the riddle by suggesting the monochrome effect is to deter biting flies. The likes of the tsetse fly can carry deadly diseases, and the dazzling array of black and white stripes is supposedly something they strive to avoid.

Places on the zebra such as the legs and face have a very narrow array of stripes, and it is suggested these are the places where deadly flies are most likely to land to deliver a bite — particularly as it lowers its head to graze.

It might sound like biologists are winging it, but for the study, vast ranges of data were collected — from where striped equid groups, such as horses, zebras and asses, live to where biting flies are found. The results showed striped species and flies overlap.


What’s even more interesting is how this theory could be applied to help humans deter mosquitoes. If the stripy hypothesis holds up, we could be seeing a lot more monochrome-clad people around the BBQ.

But before science can breathe a sigh of relief, there’s more research to be done. It’s still not known why flies steer clear of stripes, and scientists haven’t actually observed this in the wild as they are unable to get close enough to the animals to see if flies do a U-turn when they see black and white.

So while the riddle continues to smolder, we’ll leave you with another: Is a zebra white with black stripes or black with white stripes?

This article originally appeared in

Filed under