After visiting the zoo or watching an animal documentary, you may find yourself pondering this classic conundrum: Are zebras black with white stripes or white with black stripes? Though it may sound like a philosophical query, it is possible to answer this question with science. To do so, we need to take a look at the microbiology of the hairs that give zebras their dual-colored pattern.
Zebras have black skin beneath their fur, but that doesn't mean that their stripes are necessarily white on black. The majority of a zebra's hairs are white—including the ones that grow on their bellies and inner legs, where their stripes appear to end. This suggests that the quadrupeds are white with black stripes, but according to Live Science, this is still the wrong way to look at the question.
The true answer lies in a class of cells called melanocytes. Melanocytes are responsible for producing a pigment called melanin, which gives zebra hairs—and the hair and skin of all animals—their color.
When a zebra grows fur, melanocytes in their follicles dictate whether a strand will be light or dark depending on where it is on their body. In their normal state, these cells create the high-melanin black fur that makes up half of a zebra's signature coat. White zebra hairs contain no melanin, and they come from melanocytes that have been "turned off."
Genetically speaking, zebras grow black hair by default, which makes the animals black with white stripes.
While that solves one part of the zebra stripe mystery, scientists still don't know why they sport their striking stripes to begin with. One commonly held belief is that the busy pattern confuses predators trying to pick a single zebra out of the herd. Research from 2014 supports the theory that the stripes deter insects by disrupting the polarization of reflected light, which is known to attract biting horse flies. The stylish look is just a bonus.
[h/t Live Science]