When researchers painted a mannequin with zebra-like patterns, similar to those that adorn the skin of some tribal communities, they found that there were ten times fewer horsefly bites than on unstriped models.
Behavioural 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.
They found that the stripes don't deter horse flies from a distance, with both zebras and domestic horses experiencing the same rate of circling from the flies.
That stripes act to deter landings of biting flies has been suspected for over 75 years, the study team noted in their paper.
Professor Tim Caro, Dr Martin How and colleagues have been investigating the behaviours of tabanid horse flies around captive zebras and domestic horses at a livery in North Somerset, using video analysis techniques.
The study took place on a United Kingdom horse farm in Somerset that keeps both domestic horses and zebras. While there was no difference in the rate at which the flies landed on the horses' exposed heads, they touched and landed on the zebra coat far less often than either the black or white garment.
It's one of nature's more intriguing and enduring mysteries: Why do zebras have stripes? Be that as it may, video investigations uncovered contrasts in approach speed, with horse flies neglecting to back off on way to deal with zebras, which is fundamental for a successful landing.
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The answer is "very", but joking aside, scientists have recently conducted an experiment doing just that to find out why zebras have stripes. They also covered the horses with three different coats, one black, one white, and one striped (pictured) much like a zebra. Researchers used high-resolution cameras to record insects' flight trajectories as they cruised close to zebras.
Horses, however, primarily twitch and occasionally swish to ward off flies.
Flies approach the animal with the intention of landing and eating the zebra's blood.
As additional protection, zebras swish their tails nearly continuously to keep flies off, the study found.
The goal of the black-and-white markings has always been a mystery.
Together with the striped patterns findings, this anxiety suggests that zebras evolved sophisticated defense mechanisms in order to avoid infectious diseases carried by biting flies.