Researchers from the University of California, Davis have finally unlocked the answer to the question; why do zebras have stripes?
Before, scientists Alfred Russel and Charles Darwin proposed five explanations as to why zebras have stripes. Their stripes may be a camouflage, a mechanism to regulate temperature, a body part which initiates social functions, a weapon to visually confuse predators, and a way of avoiding attacks from parasites, such as biting flies.
To find out the answer, the team made a map of the geographic distributions of various horse, asses, and zebra species. They noted important characteristics such as thickness of mane, locations where they thrive, and the intensity of the stripes found on the zebra's bodies. They also compared the data with other factors such as the presence of predators, temperature levels, and the presence of glossinid (tsetse flies) and tabanid (horse flies).
Analysis of the data showed that zebras developed their stripes as a defense mechanism against blood-sucking flies.
In Africa, the distribution of tabanids is unknown and to find out where they thrive, the researchers created a map showing the best breeding conditions for the tabanids. They discovered that these breeding conditions are closely associated with the natural evolution of the zebras to having stripes.
"I was amazed by our results," UC Davis professor of wildlife biology and lead author Tim Caro said in a press release."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."
Furthermore, they discovered that zebras were the only species to develop stripes due to the presence of biting flies because their hair is shorter than the fly's mouthpart. The zebra's shorter hair makes them more susceptible by the irritation caused by the fly's bite.
Although this study answered an imperative question, it gave birth to another one: Why do flies stay away from striped surfaces? Caro explained in a press release that more studies should be conducted to know the answer to this question.
Further details of the study were published in the April 1 issue of Nature Communications.
