I can remember that even as a child I wondered about zebras. They look like horses in just about every way except the stripes. Why do zebras have stripes?
When I raised that question in my high school biology class, I was told it was for camouflage. That explanation satisfied me until I was in the army where I was taught how to camouflage myself in combat. Our combat uniforms were striped. The leaders told us that the stripes would only work if there were movement around us, and if there wasn’t, we should stand perfectly still. Watching zebras in the wild, to me the stripes seemed like a flag saying “here I am.” I realized that a striped deer in the Michigan woods wouldn’t last very long during hunting season.
A good friend sent me a clipping of an AP report published in the February 23, 2019 issue of The Herald Bulletin in Anderson, Indiana. It finally answered my question of why do zebras have stripes? The article told about research by scientists at the University of Bristol and the University of California at Davis. They dressed horses in white striped coats. The striped horses had significantly fewer horseflies landing on them than the ordinary horses. The striped coats apparently disrupted the visual system of the horseflies. The leader of the research team said that when flies get close to the stripes, they tend to fly past them or bump into them.
In much of Africa, there is a fly that carries a parasite that causes “sleeping sickness” or Trypanosomiasis. The parasite is transmitted to humans and animals by a blood-sucking insect, the tsetse fly. For a zebra, the tsetse fly is the number-one enemy. A healthy zebra can outrun a lion, and most other threats to their survival are of minimal efficiency. Getting away from flies is virtually impossible.
The stripes are a design feature of zebras. In northern areas tsetse flies don’t exist, so deer and horses don’t have stripes. An animal’s external appearance is a genetically determined feature. Why do Zebras have stripes? They are a classic example of how a change in appearance can protect against various kinds of enemies.
This new area of research shows one more example of God’s design in producing a genome that allows animals and plants to survive in a world of constant change.
–John N. Clayton © 2019
