Stripes did not deter flies from a distance as they circled horses and zebras at similar rates.

The researchers videoed horse flies as they tried to prey on captive zebras and domestic horses at a livery in North Somerset, England.

'Most biologists involved with research on mammal coloration accept that this is the reason that zebras have stripes.'Īfrican horse flies carry diseases such as trypanosomiasis (which cause fever, headaches, joint pains and itching and can later on include behavioural changes, confusion and poor coordination) and African horse sickness that causes wasting. 'We showed that horse flies approach zebras and uniformly coloured horses at similar rates but that they fail to land on zebras - or striped horse coats - because they fail to decelerate properly, and fly past them or literally bump into them and bounce off,' he said.įlies manage to land on zebras less often than horses. In one experiment, the researchers put cloth coats bearing striped patterns on horses and observed that fewer flies landed on them than when the same horses wore single-colour coats.īehavioural ecologist Tim Caro of the University of California-Davis, who is the lead author of the research published in the journal PLOS ONE, said that only the fly attack hypothesis stands up to scrutiny.

thermoregulation, with stripes setting up convection currents along the animal's back.

a social function like individual recognition.

There had been four main hypotheses to explain why zebras have their stripes: Their stripe patterns vary among individuals, with no two alike. Close cousins to horses and donkeys, the world's three zebra species roam Africa's savannas eating a variety of grasses.

Zebra with no stripes