Horses helping solve mystery of zebras’ stripes

Credit : School of Biological Sciences, University of Bristol

Monday 25 February - 16h18 | Ian Clayton

Horses helping solve mystery of zebras’ stripes

Why do zebras have stripes? An experiment involving horses is providing new clues into the age-old question.

 - Horses helping solve mystery of zebras’ stripes

As several media outlets have reported regarding a UK research study on this issue, possible explanations for zebras’ stripes have ranged from them being camouflage, to social signalling, to keeping the animals cool. But a team from the University of Bristol in Great Britain decided to test another theory by going to a farm and dressing up a group of horses in zebra-print coats.

Observing horses and zebras out in the fields, the researchers wanted to see whether the stripes might deter flies from landing on the animals. Brigit Katz
described the issue on

“Just like when you’re flying on an airplane, a controlled landing is extremely important for flies,” 
Tim Caro, lead study author and behavioral ecologist at UC Davis, tells Popular Science’s Jessica Boddy. “They don’t want to break a leg or damage an eye. So when a fly comes in looking for a blood meal they need to slow down. Somehow stripes are preventing that from happening.”

As part of their research, the researchers outfitted the horses in different solid-coloured coats as well as a striped zebra coat. "Fewer flies landed on the striped jacket, compared to the black and white ones," Katz added. "But the stylish zebra-striped attire did not stop flies from landing on the horses’ unadorned heads."

As a study co-author noted in the Smithsonian report however, more work remains to be done: "“I wouldn’t want to suggest that horse-wear companies sell striped livery for their riders yet,” he said.

Further reading...