I was catching up on my reading during my recent trip to California, and I ran across a blurb in the July 2016 issue of National Geographic magazine entitled “Patterns Puzzle Predators”. It begins by saying —
“If a zebra zigs, with its stripes make a predator zag? That’s the idea behind motion dazzle, a century-old hypothesis about why some animals sport high-contrast patterns. Unlike camouflage, which allows prey to blend into surroundings, motion dazzle may mask movement, confusing predators about direction and speed.”
This makes sense to me. Humans tried the same thing during World War I by painting ships with zebra-like patterns.
But a team at the University of California at Davis may have found a different reason for stripes. Their January, 2016 study agrees that the purpose is not camouflage — “The results from this new study provide no support at all for the idea that the zebra’s stripes provide some type of anti-predator camouflaging effect,” says Tim Caro, one of the study’s collaborators. They also rule out social reasons.
So why the stripes? In earlier studies, this same team found evidence suggesting the stripes provide an evolutionary advantage by discouraging biting flies, which are natural pests of zebras.
Why didn’t they just ask a zebra?
The abstract of the January, 2016 study is at https://www.ucdavis.edu/news/zebra-stripes-not-camouflage-new-study-finds . The pictures are from Google.