Scientists Uncover New Reason for Zebras' Stripes

Volodymyr Burdiak  Shuttestock

Volodymyr Burdiak Shuttestock

But what about a zebra's stripes?

There had been four main hypotheses about the advantages zebras accrued by evolving stripes: camouflage to avoid large predators; a social function like individual recognition; thermoregulation, with stripes setting up convection currents along the animal's back; and thwarting biting fly attacks.

Besides the costume changes-scientists dressed up horses and zebras in black, white, and black and white stripes-they also watched up close when flies tried to land on zebras and made detailed videos to record the flies' flight patterns when they cruised close to zebras.

Horse flies are a widespread problem for domestic animals so mitigating techniques, such as the development of anti-fly wear created to resemble zebra stripes, may, from this research, be an interesting outcome for animal health and wellbeing. Hoping to find out how flies interacted with the different species, the team conducted careful observations of the animals-and dressed the horses up in snazzy, zebra-print coats.

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.

Well, it appears stripes make awful landing strips, bamboozling the fierce blood-sucking flies that try to feast on zebras and carry deadly diseases.

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It just took one seriously obsessed scientist, some horses and a couple zebra parkas.

Study leader Professor Tim Caro, from the University of California at Davis, US, said: "Once they get close to the zebras... they tend to fly past or bump into them". "They don't want to break a leg or damage an eye".

Indeed, the flies landed on the zebras at an average of one-fourth of the rate they landed on the horses. He found horseflies had no problem spotting either group, but they were awful at landing on the striped horses.

According to Caro, he was doing the horses a favor.

Why, then, aren't all equids adorned with this dazzling pattern? However, the only explanation that has stood up to experimental verification suggests that the stripes serve to deter insects, which can sometimes carry deadly diseases.

This research provides new evidence for the theory that zebras evolved dichromatic striped coats to evade biting flies and has considerable implications for the horse industry. Now, a new study suggests that the stripes may have a different objective entirely. In their study, they write that the contrasting stripes might disrupt the insects' optic flow, or their sense of motion of the objects around them.

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