I guess I never really gave it much thought. I sort of believed the answer was pretty much like why leopards have spots. Now, researchers say they have finally discovered  the answer. The black-and-white pattern helps repel bloodthirsty, disease-carrying flies by disrupting their vision and making it difficult for the biters to land, according to a study by California scientists.

According to an article in USA Today, the purpose of the stripes are camouflage; they confuse predators; they manage the animals' body heat; they have an unknown social function; and they ward off tsetse and horseflies.