Horse flies and tsetse flies were responsible for the evolution of the zebra's white and black stripes, according to University of California - Davis researchers.
Is a zebra black with white stripes or white with black stripes? While the answer to this century-long riddle remains a mystery, researchers from University of California - Davis have at least solved the mystery behind the origin of these strips.
Researcher found that biting flies like horse and tsetse flies were responsible for the evolution of the zebra's white and black stripes, according to a press release. The zebra uses its stripes for various purposes like camouflaging itself, disrupting predatory attack by visually confusing carnivores, as a heat management tool and to avoid ectoparasite attacks.
"I was amazed by our results," said lead author Tim Caro, a UC Davis professor of wildlife biology in a press statement. "Again and again, there was greater striping on areas of the body in those parts of the world where there was more annoyance from biting flies."
For the study, researchers analyzed the geographical location of seven different species of zebras, horses and asses, and of their subspecies, noting the thickness, locations and intensity of their stripes on several parts of their bodies. They then compared this data with different influencing factors including woodland areas, ranges of large predators, temperature, and the geographic distribution of glossinid (tsetse flies) and tabanid (horseflies) biting flies.
All the factors were ruled out but one - avoiding biting flies. This gave rise to other questions. Why did only zebras and not other hooved animals living in the same geographical location develop the stripes? Researchers explained this dilemma saying zebra hair is shorter than the mouthpart length of biting flies, so zebras may be particularly susceptible to biting flies.
"No one knew why zebras have such striking coloration," Caro said. "But solving evolutionary conundrums increases our knowledge of the natural world and may spark greater commitment to conserving it."
One solved mystery led to the development of another. Why do biting flies avoid striped surfaces? Caro said that further studies need to be conducted to understand this phenomenon better.
A previous study conducted last December offered similar findings that suggested the stripes create an optical illusion that dazzles predators and masks movement
The study was published in the online journal Nature Communications.
