Researchers solve the mystery behind the striped fur of zebras

According to a study that refutes a belief which dates back to Darwin. The characteristic black and white striped fur of zebras do not help the animals to stay cool in the hot sun.

A discussion has taken place among researchers on why zebras have their signature black and white stripes which suggests that it keeps them cool in the sunshine.

The black stripes get warmer than the white areas, and the theory states that this creates small vortexes when the hotter air above the dark fur meets the cooler air above the white fur. According to the theory these vortexes works as a fan to cool the body.

To test this theory, researchers from Lund University in Sweden filled big metal barrels with water and covered them with skin imitations in different colours such as black and white stripes, black, white, brown and grey.They then placed the barrels in the sun and later recorded the temperature in each barrel.The black one was the hottest and the white one the coolest. The striped and grey barrels were similar, and in these the temperature did not go down.

"The stripes didn't lower the temperature. It turns out stripes don't actually cool zebras," said Susanne Akesson, from Lund University.Eight years ago Susanne and her colleagues from Hungary and Spain presented another theory, in which they claim that the bright fur works as an optical protection against blood-sucking horse flies and other insects that bite.

Horseflies are attracted towards polarised light, the kind of light that appears when sunbeams are reflected on a dark surface. If the sunbeams are reflected on a white surface there will be no polarised light which results in protection.