Why zebras have stripes? Scientist shed light to the century old question

The African savanna is a very unforgiving place to live without a herd...Few moments in my life made me reflect on the strength that comes from living within a community than the one I witnessed at the Ngorongoro Crater, in Tanzania. The Ngorongoro Crater, is the world's largest inactive, intact and unfilled volcanic caldera. The crater was formed when a large volcano exploded some 2 million years ago, leaving a wealth of nutrients that makes this place particularly rich in wildlife.

It was there, during a cold early morning that I saw a dazzle of zebras staring at a pride of lions feasting on a zebra that they had killed overnight. I could not help but to feel compassion for the zebras as they stared together in line, some 100 meters from the lions. It is of course the circle of life and you never feel more alive than in nature… But this experience got me thinking whether the stripped coat of the zebras actually offers protection against predators out in the plains.

There are over 18 different theories that aim to explain why zebras have stripes. Some are more creative than others, but the most accepted ones are:  

1. Protection from predators: Lions and other predators are colour blind, which could help explain how the stripped pattern can work as a disguise during the night which is when predators are most active.

2. Protection from the heat: Under the sun, the black stripes are up to 12-15 Celsius warmer than the white stripes, creating a sort of “mildly turbulent air”. Researchers have found stronger stripping patterns in warmer areas where zebras receive more sunlight.

3. Protection from flies: Tsetse flies and horseflies transmit diseases like sleeping sickness, African horse sickness and equine influenza which can prove to be fatal. This year, a group of evolutionary biologists from the University of California published the results of an experiment that they conducted to support the disease protection theory. For the experiment, they dressed up horses with zebra coats and placed them along other horses and zebras. They observed how horseflies hovered around zebras and horses, but far fewer flies landed on zebras – or horses with striped coats. It seemed that flies have trouble landing on stripped patterns! (I will certainly consider wearing a zebra pattern next time I am on safari)

At last, protection from disease transmitted by flies seems to be the leading hypothesis at the moment. But despite the increase in rigorous scientific research, scientist are having trouble agreeing on one single theory...So perhaps stripes evolved to solve multiple problems???