Why did zebras lose their stripes as they became quagga? No one knows. Perhaps a better question is: Why did zebras develop stripes in the first place? To protect them from the tsetse fly, say some biologists—oddly enough, the insect can't see stripes. In the Great Karroo, unlike other parts of Africa, there aren't many tsetses. So the theory is that the quagga's coat evolved to mimic the surrounding plains and better evade another annoyance of African life: lions.