Why do zebras have stripes? To keep the flies off, say scientists

The animals' distinctive coats help them keep off the insects that try to feast on them and carry deadly diseases.

Researchers put striped coats on horses to see how many insects landed on them and compared the results with horses covered in plain, single-coloured coats.

They filmed the horse flies as they tried to prey on captive zebras and horses kept on a domestic farm in Somerset, and found that the insects approached the animals at similar rates.

But once they began to circle them, the flies managed to land on zebras less than a quarter as often as they did on the horses.

Researchers put a zebra stripe coat on a horse to compare the impact on insects trying to land on the animals

Tim Caro, lead author of the report which was published in the journal PLOS ONE, said on approach, the flies "fail to decelerate properly, and so fly past them or literally bump into them [zebras] and bounce off".

University of Bristol biologist and study co-author Martin How, said stripes may dazzle flies once they get close enough to see them with their low-resolution eyes - much like how pilots can become dazzled by the sun.