July 19, 2024, 5:14 am | Read time: 3 minutes
Is a zebra black with white stripes, or is it actually the other way around? This question fascinates more than just researchers. PETBOOK has therefore set out in search of clues and explains what is known about why these animals have this characteristic look in the first place.
Whether zebras are actually white- or black-striped has fascinated scientists ever since this horse-like animal species was first discovered. The reason zebras have this highly visible and striking pattern has long been the subject of research. You would think that they would be particularly conspicuous to predators. However, the opposite seems to be the case, as scientific studies have shown. However, there are many other theories about one of the most famous patterns in the animal kingdom.
Zebras must produce black pigments for their stripe pattern
The central question of whether zebras are white- or black-striped can be easily answered by looking at the animals’ skin. This is mainly found around the eyes and snout of the zebra, and it is black. This provides the first indication of the true color of these animals.
This is how the English-language encyclopedia Britannica describes it in an article, going right down to the root of the animal’s hair. The entire coat of a zebra, whether black or white, grows from follicles containing melanocyte cells. These produce pigments, in the case of the zebra, this is eumelanin, which produces black fur. The white coat, on the other hand, represents the absence of this pigment. According to Britannica, chemical messengers in zebras determine which melanocytes release the pigment to which part of the coat, resulting in the black and white pattern of the zebra. Since white stripes only exist because they lack pigment, black is considered the “standard color” of a zebra.
Dr. Greg Barsh from the HudsonAlpha Institute for Biotechnology in the US state of Alabama also confirms this in the podcast. The expert on the genetics of color variations gives the unequivocal answer that zebras are mostly black. As to the reason for his conviction, he says: “The reason we know this is that some of the early work we did on zebras was in collaboration with a zebra owner. We visited her once and asked her the exact same question.” The collaborator shaved off some hair and then realized that zebras have completely black skin.
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Stripe patterns in zebras are a biological mystery with many possible explanations
However, despite many years of research, there is no definitive explanation as to why zebras have this particular appearance. There are scientific studies and theories in many directions. These include, for example, the assumption that a certain stripe pattern promotes social cohesion. Or that it creates a camouflage effect so that predators cannot see them properly.
In 2015, scientists believed they had found the definitive answer to this question. They examined patterns in a wide variety of zebra distribution areas. Using 29 geographically and locally occurring stripes, they showed that they adapt to climatic conditions. In other words, zebras are more black in warmer areas and more white in colder areas. This had an effect on stripe thickness and expression on the legs and rump alike.1
Another well-studied theory was confirmed in 2020. This theory states that zebras are less frequently approached by biting flies due to their stripes. This is because the stripes disrupt the optical flow patterns that flying insects need to land on. This hypothesis has already been proven on horses painted with stripes.2 In the end, there is probably no single explanation for the black and white stripes on zebras, even if scientists are of course still looking for one.