Forget about what you’ve learned in school. According to a new study, zebras are not equipped with stripes to fool predators. In fact, the black-and-white patterns’ sole function is to shield the animals from biting flies, the new research suggests.
Amanda Melin, lead author of the study and researcher with the University of Calgary, in Canada, explained that previous studies that had linked the stripes to a camouflaging function were biased from start because they had based their conclusions on what the human eye can perceive.
In the new study, researchers made estimates of what the eyes of African predators such as lions and hyenas can see. Measurements were made during daylight, night, and twilight.
For the new research, Melin teamed up with UC Davis’ Tim Caro, who has been conducting other studies on zebra stripes and their function. In a study published last year, Caro concluded that the stripes protect the herbivores from pesky, blood-sucking insects.
Study authors argue that zebra stripes play no role in camouflaging the creatures because predators usually rely more on hearing and their sense of smell than vision to track down the animals. Past studies had suggested that the stripes help zebras blend in with the environment by blurring their outline against the natural background.
Caro said that he and his colleagues found zero evidence to back the camouflage function hypothesis. He noted that even Charles Darwin and British naturalist Alfred Russell Wallace engaged in hot debates over the issue.
The recent study was published Jan. 22 in the online journal PLOS ONE.
The research team based their conclusions on digital imagery and computer models of what a zebra may look like to a pair of predator eyes. Researchers also measured the light contrast, width, and brightness of the black-and-white patterns to estimate the distance from which stripes would be visible to humans and predators.
The findings revealed that in full daylight, predators have a real hard time to see stripes beyond 164 feet. Nevertheless, from the same distance stripes were visible to the human eye. Same thing happened at twilight (predator’s favorite part of the day to hunt) from a 98-foot distance.
At night, both predators and humans were unable to distinguish the stripes beyond 30 feet. Past research had found that on moonless nights, the stripes help herbivores to camouflage in woodland areas where black stripes were taken for tree trunks and white stripes were mistaken for shafts of light through those trunks.
Image Source: Pixabay