Today’s Wonder of the Day was inspired by Isaac. Isaac Wonders, “Why are zebras black and white?” Thanks for WONDERing with us, Isaac!
Although most people tend to think of the zebra as a white animal with black stripes, scientists have discovered that the zebra is actually a black animal with white stripes. Much like a fingerprint, the stripes on a zebra are unique. No two animals have the same pattern. But why do they have stripes at all?
Whether roaming around the zoo or running across the Serengeti, the zebra is an animal that sticks out. The zebra's black and white striped pattern could not be more obvious. That might not be the case when it comes to a zebra's predators, however.
In the wild, the zebra's main predator is the lion, an animal known to be color blind. Scientists who study animals — called zoologists — believe that the zebra's pattern is a sort of camouflage that helps it hide from predators.
Imagine that you can only see black, white and shades of gray. A solid-color dark horse standing in light-colored tall grass would be very obvious. A zebra's stripes, however, help it blend in with grasses and brush, making it much more difficult to see.
Some biologists also believe the zebra's stripes may be helpful when zebras run in a herd. When a large number of zebras move together, their stripes could appear to be one large animal running. This illusion may confuse predators, making it difficult for them to pick out a single animal to attack.
Recent studies, however, have cast doubt upon the popular camouflage theory. Researchers have noted that many other grazing animals in Africa have not developed similar striping to deter predators.
Instead, researchers have discovered that stripes may have two other purposes: regulation of body temperature and deterring biting flies. Scientists began studying these possibilities when they noticed that zebras in hotter areas tended to have more stripes.
In a large study of African zebras, researchers found that zebra stripes correlated closely with temperature and precipitation, not the prevalence of lions. This led them to doubt the camouflage theory and look for other explanations.
Although no hard conclusions can yet be drawn from these new studies, scientists now believe zebra stripes may help keep zebras cooler. Some scientists suggest that air moves more quickly over black stripes and less quickly over white stripes, causing air to swirl where the stripes meet and thereby cooling the zebra's skin.
Other researchers believe zebras in hotter areas have more stripes to deter disease-carrying biting flies, such as tsetse flies and horseflies. Researchers have learned that biting flies, which prefer hot weather, don't like to land on striped surfaces. The presence of more stripes in warmer areas could be a natural defense against these biting flies.