Zebra’s stripes aren’t a camouflage hiding them from predators, a recent study has established, generating more confusion regarding what use the patterns might have after all.
The surprising findings have been featured in the journal PLOS ONE, on Friday, January 22. They were based on research led by Tim Caro, professor of wildlife biology at the University of California at Davis, and Amanda Melin, evolutionary ecologist and biological anthropologist affiliated with the University of Calgary, Canada.
Previously, Caro had determined that zebras’ stripes might be an effective way of protecting them against blood-sucking tabanid flies.
Basically, the thinner the stripes in their patterns, the more unappealing the herbivores become to insects, due to the way that the light is reflected by their coats.
Now, researchers wanted to see if the markings may also serve as an effective camouflage as speculated by prior studies, which had suggested the black and white lines perfectly resemble the trees and the beams of light peering through them, thus allowing the zebras to effectively conceal themselves.
The long-held belief was that the patterns can render animals virtually undetectable in their surroundings, and therefore less at risk of being attacked by potential predators, but study authors wanted to investigate the hypothesis more thoroughly.
With this purpose in mind, they used digital photos showing zebras in one of their natural habitats (Tanzania’s grasslands) and applied various filters to those images, in order to mimic the way the equine creatures would be perceived by other zebras, as well as by predatory animals (such as hyenas and lions).
By assessing how broad the zebras’ stripes were, and how luminous their coats appeared to be, researchers were able to discover the greatest distance that the animals could be standing at, in order to have their patterns still discernible by other members of the same species or by would-be predators.
Allegedly, when the zebras are in areas completely devoid of trees, they can be spotted by carnivores just as effortlessly as other quarry having the same size, but more plain coloring (like topi and waterbuck).
In addition, at distances surpassing 164 feet during daytime and 98 feet during nighttime, the stripes can no longer be seen by predators, although they can be easily identified by humans. In fact, when it’s pitch dark, the zebras could be standing a mere 29 feet away, without their coat markings being noticed by any other animals.
Basically, this proves that while observations made by the human eye may suggest otherwise, zebras’ stripes don’t actually play any role in allowing members of this species to blend in more easily with their surroundings.
That’s because at distances where these markings would be seen, zebras would already make their presence felt because of their noises or scent.
The same researchers also investigated the possibility that the patterns might assist the herbivores in interacting with each other more easily.
They discovered that despite the fact that the stripes can be distinguished from greater distances by other zebras than by their predators, they don’t actually play any role when it comes to bonding.
Apparently, other equine animals without such patterns can identify their peers just as easily as zebras do, so the markings don’t provide a social advantage after all.
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