Zebras have stripes to repel bugs, such as biting flies. A research team from the University of California found that biting flies that normally attack animals like zebras avoid the black and white stripes.

The research team studied several species of zebra, observing the location, thickness and intensity of the stripes on the animals' bodies. They noted the geographical location, temperature and predators of the animals. The team noticed a large amount of biting flies in the regions where zebras lived. Curiously, the zebras weren't affected by the blood-sucking parasites. Bites from the flies in the area had the potential to cause weight-loss, lack of milk production, sleeping sickness, equine anemia, equine influenza and blood loss in their hosts.

Before these findings, scientists and researchers theorized that a zebra's stripes could be a means of communication, a way to confuse carnivores, or a form of heat management. Since the 1800s, researchers were hard at work to solve the puzzle. Although many theories existed, they could never prove any of them. The evolutionary stripes of zebras allow them to repel the parasites naturally. However, scientists face another conundrum: why biting flies avoid striped surfaces. Researchers plan to continue their studies about the habits of the biting flies and the dangers they present to other animals in the wild.