Since the time of Charles Darwin and Alfred Russel Wallace, researchers were always curious to find out why the zebra evolved to have coat with such stripes, which does not help to camouflage in the environment like the stripes of other animals do. There are many theories supporting the function like signaling during social communication or disguising during the dawn or dusk time in tall grasses. The most convincing reason of all, supporting the stripes of the zebra says it was evolved to dazzle the big predators as well as small insects.
In a recent study researchers have using computer simulation, finally explained how the stripes present on the zebra coat confuse the approaching predators. When the zebra moves its stripes establish an optical illusion and make difficult for the predator to concentrate and losing the target. To validate this theory both researchers from University of London Dr How and colleague Prof Johannes Zanker, inspected various photographs and videos of zebras. On preparing a simulation model based on motion algorithm found that the zebra stripes creates motion signals giving deceitful optical message in the brains of approaching predators irrespective of its size.
The researcher said that the antagonistic visual information is blending of two noted optical illusions: the barber pole illusion and the wagon wheel effect. During the barber pole effect the stripes on the barber pole appears to be moving spiraling upwards as it moves. Whereas in wagon wheel motion the wheel appears to be moving clockwise however after reaching a certain speed the wheel appears to be moving in anti clock wise direction. Thus the stripes of zebra take advantage of these two type illusion to defend itself as the attacking animals get confused which part of it is which especially while observing more than just one zebra.
Dr How further added that the broad stripes on the zebra flank and the narrow one on the neck and back provides the herd of zebras, with astonishing motion signals which easily confuses the predators. The predator or pest inaccurately calculates the direction of the moving zebra and leading to an inept attack.
Researchers believe that the other animals with similar patterns like snakes and humbug damselfish, is benefited using the same effect. On better understanding of these patterns, similar dazzle effect can be an added advantage for implementation by the soldiers during wartime to camouflage their tanks and battleships.
Source: BBC News