Zebras are iconic with their distinctive decoration, but have you ever wondered if zebras are white with black stripes or black with white stripes? The stunning black and white coloration of the zebra’s skin stands out in stark contrast to the dry, brown-sandy pastures and forests of the savannas of their homelands in East and South Africa. These stripes are unique to each individual. Today, there are three species of zebras – the flat zebra (Equus quagga), the mountain zebra (E. zebra) and the zebra zebra (E. grevyi) – and each of these species also has a different pattern of stripes. For some, the darker parts of their skin are black, while others are browner, and some have streaks only on the body but not on the legs. An extinct subspecies of the plain zebra, called the quagga (E. quagga quagga), had minimal streaks on its head, mane and neck, writes The Quagga Project. Despite these different patterns and coloring, all zebras have the same skin color: black, says Tim Caro, a behavioral and evolutionary ecologist and conservation biologist at the University of California. However, this does not answer the question of whether their fur is black with white stripes or vice versa. For this we need to look at the zebra melanocytes or the cells that produce pigment for their fur.
Although zebras have black skin, various developmental processes determine the color of their hair, just as a fair-skinned person can have dark hair, Caro said. In fact, zebras have more light bristles than dark ones – their bellies are usually light – so zebras may appear to be white with black stripes. But this is not because every piece of hair – both light and dark – grows from a follicle full of melanocyte cells, wrote in 2005 in the Journal of Investigative Dermatology. These cells produce a pigment that determines the color of hair and skin. This pigment is known as melanin; a lot of melanin results in darker colors, such as dark brown or black, while less melanin results in lighter colors, such as hazelnut or blond. The black fur of zebras is full of melanin, but melanin is missing in white fur, essentially because the follicles that make up the stripes of white hair have “turned off” the melanocytes, which means they don’t secrete pigment. The exact biological processes behind the zebra stripes are not known, but in African striped mice that have light and dark stripes, the Alx3 gene is more active in the light stripes than the dark stripes, according to a 2016 study in the journal Nature. Alx3 effectively stops the main regulatory gene responsible for the development of melanocytes, which leads to blonde hair, the researchers found. So why is the zebra black with white stripes? This unique coloring pattern can keep away biting flies and mosquitoes. A study published in 2020 in the Proceedings of the Royal Society B found that African horseflies landed less often on horses wearing striped or checkered rugs than on horses wearing one-color rugs. And these biting flies can transmit diseases that are fatal to zebras.
