Researchers Discover Why Zebras Have Stripes

According to research published in the Journal of Experimental Biology, zebra fur is thinly striped and sharply outlined to thwart horsefly attacks. “These characteristics specifically eliminate the outline of large monochrome dark patches that are attractive to horseflies at close distances,” adds Phys.Org. “The team theorizes that the thin back stripes serve to minimize the size of local features on a zebra that are appealing to the biting flies.” From the report: The team found that tabanid horseflies are attracted to large dark objects in their environment but less to dark broken patterns. All-gray coats were associated with by far the most landings, followed by coats with large black triangles placed in different positions, then small checkerboard patterns in no particular order. In another experiment, they found contrasting stripes attracted few flies whereas more homogeneous stripes were more attractive. […]

The team found little evidence for other issues that they tested, namely polarization or optical illusions confusing accurate landings such as the so-called “wagon-wheel effect” or “the barber-pole effect.” Now the team want to determine why natural selection has driven striping in equids — the horse family — but not other hoofed animals.