Are zebras white with black stripes or black with white stripes?


Zebras are iconic for their distinctive coats, but have you ever wondered if zebras are white with black stripes or black with white stripes?

According to African Wildlife Foundation.

These stripes are unique to each individual. There are three species of zebra today: the plains zebra (Equus quagga), the mountain zebra (E. zebra) and Grévy’s zebra (E. grevyi) – and each of these species also has a different stripe pattern. For some, the darker parts of their skin are black, while others have a browner coloration, and some have stripes only on the body but not on the legs. An extinct subspecies of the plains zebra called quagga (E. quagga quagga) had minimal scratches on the head, mane and neck, according to The Quagga project.

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Despite these different patterns and colors, all zebras have the same skin color: black, said Tim Caro, behavioral and evolutionary ecologist and conservation biologist at the University of California at Davis. However, that doesn’t answer the question of whether their fur is black with white stripes or vice versa. For this, we must turn to the melanocytes of the zebra, or the cells that produce the pigment in their fur.

Although zebras have black skin, different developmental processes determine the color of their fur, just like a light-skinned person can have dark hair, Caro said. In fact, zebras actually have more light hair than dark – their bellies are usually light – so it can appear that zebras are white with black stripes.

But this is not the case. Here’s why: Each strand of hair – both light and dark – grows from a follicle filled with melanocyte cells, according to a 2005 review 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 leads to darker colors, like dark brown or black, while less melanin leads to lighter colors, like hazelnut or blonde, Previously reported live science. The black fur of zebras is full of melanin, but the melanin is absent from the white fur, essentially, because the follicles that make up the stripes of white hair have “turned off” the melanocytes, which means that they do not produce. pigment.

The production of melanin from melanocytes is “prevented during the development of a white hair, but not a black hair,” Caro told Live Science in an email. That is, for zebras, the default state of animals is to produce black hairs, making them black with white stripes, according to Brittanica.

African striped mouse (Rhabdomys pumilio) have light and dark stripes along their hairy body. (Image credit: Utopia_88 via Getty Images)

The exact biological processes behind zebra stripes are not known, but in African striped mice (Rhabdomys pumilio), who have light and dark stripes along their hairy body, the gene Alx3 is more active along light bands than dark bands, according to a 2016 study in the journal Nature. Alx3 effectively shuts down a major regulatory gene responsible for melanocyte development, leading to light-colored hair, the researchers found.

So why is the zebra black with white stripes? This unique pattern can ward off biting flies, according to research by Caro and colleagues. In a study published in 2020 in the journal Proceedings of the Royal Society B, they found that African horseflies alighted less frequently on horses wearing striped or checkered blankets than on horses wearing plain blankets. These biting flies can carry deadly diseases to zebras.

“There are indeed very few mammals with contrasting stripes like a zebra,” Caro said. “The okapi has similar stripes on the rump, but other than that, no other species has really distinct black and white stripes. I guess the fly deterrent function is unique to equines as they are very susceptible to diseases carried by some biting flies in Africa. “

Originally posted on Live Science.


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