It’s a question that has been debated since the time of Darwin, and now a Calgary researcher is one step closer to answering the age old puzzle: “Why do zebras have stripes?”
Contrary to popular belief, zebra stripes are not for camouflage, a University of Calgary study has found.
The researchers, from the University of Calgary, University of California and Japan’s Kyushu University, passed digital images taken in the field in Tanzania through filters simulating how zebras appear to their main predators. They also measured the widths and light contrasts of zebras to estimate the longest distance at which they could be spotted by predators.
“We were able to estimate the distances at which lions and spotted hyenas, as well as zebras, can see zebra stripes under daylight, twilight, or during a moonless night,” said the study’s lead author Amanda Melin, an assistant biological anthropology professor at the U of C.
The researchers found that in the open, treeless areas where zebras usually hang out, lions could see zebras just as easily as they can see other potential prey. And in wooded areas, stripes are hard for predators to make out, indicating they don’t help zebras hide.
So, why the stripes? Before taking part in this study, UC Davis wildlife biology professor Tim Caro published research with others suggesting that the zebra’s stripes provide an evolutionary advantage by discouraging biting flies, which are natural pests.