The Zebra's Stripes

Are zebra stripes just a random creation of nature? If not: What is their function? Which evolutionary advantage do they confer?

This hypothesis has since been tested and could not be confirmed. Zebras are often caught by lions. Also, most mammalian predators see at least as well as humans, and can smell and hear much better. Good supporting evidence was not found. A camouflage effect does not seem to be a likely explanation for the zebra's stripes.

In 1981, almost 110 years after Darwin's und Wallace's hypothesis, another scientist (Dr. Waage) developed a new hypothesis: Tsetse flies and horseflies are vectors of dangerous diseases, e.g. the nagana pest which is often deadly for zebras. Flies have very different eyes than mammalian predators and fewer neurons to process the visual information. Could zebra’s stripes be effective in evading these disease-carrying flies? And indeed: In the past 35 years a number of experiments have confirmed this. Animal models painted with zebra stripes attracted far fewer horseflies than those painted uniformly black, brown, gray or white. Furthermore, it could be shown that the spacing of zebra stripes was in a range optimally confusing the horseflies.

Not quite. Some scientists doubt the evidence in favour of flies and found evidence that the spacing and density of zebra stripes is correlated with average temperatures of their habitats, supporting a thermoregulation hypothesis. Although protection against tse-tse and horseflies seems to be the best explanation at the moment, the case is not closed. Scientists must continuously review, doubt, and – where necessary – revoke existing answers. There is more than enough work for the next generation of young scientists. ––– PS: Not all zebra camouflage experiments are published – see this image of zebra paintings on a street in Portugal.