Why do zebras have black and white stripes?

Where does this strange appearance come from?

Zebras attract attention with their black and white striped coats, a unique signature in the animal kingdom. For a long time, researchers have wondered about the origin and function of these peculiar stripes. Several hypotheses have been put forward, ranging from simple camouflage to a social role. However, recent studies now provide a more precise answer.

What is the real reason for their stripes?

The main function of the stripes is to protect zebras against biting insects, especially tsetse flies and horseflies, which are very numerous in their habitat and are vectors of diseases.

How do the stripes repel insects?

Insects are attracted to dark, uniform surfaces. However, the black and white stripes create a complex optical illusion that disrupts their visual perception. Experiments have shown that flies have much more difficulty landing on a striped surface than on a plain one. More specifically, polarized light, which insects use to spot their targets, is unevenly reflected by the stripes, making the zebra almost invisible to their eyes. This mechanism significantly reduces bites, thus limiting the risk of infections.

Even though other hypotheses exist, such as helping with thermal regulation, individual recognition, or group camouflage, the anti-insect role is now considered the main cause of this remarkable adaptation.

Sources (in English):

• https://www.ucdavis.edu/curiosity/news/how-zebra-stripes-disrupt-flies-flight-patterns
• https://www.nature.com/articles/s41598-022-22333-7
• https://www.theguardian.com/science/2019/feb/20/why-the-zebra-got-its-stripes-to-deter-flies-from-landing-on-it