Why Do Zebras Have Stripes?

For more than a century, scientists have puzzled over one of nature’s most striking visual features: the black-and-white stripes of zebras. Since the days of Charles Darwin and Alfred Russel Wallace¹, researchers have proposed numerous explanations

for why zebras evolved such unusual markings. Ideas have included camouflage from predators, social recognition among zebras, temperature regulation, and even visual confusion that might make it harder for lions to single out individual animals in a herd. Despite the abundance of theories,

modern research has gradually narrowed the field, and today many scientists believe that protection from biting flies is the most likely primary reason zebras have stripes. The camouflage hypothesis was one of the earliest explanations. At first glance, it seems reasonable that stripes might help zebras blend into tall grass or confuse predators.

However, studies examining how lions and hyenas perceive zebras suggest that these predators have lower visual acuity than humans and often cannot distinguish stripes from a distance. In the open savannas where zebras commonly live, their striped coats do not appear

to make them significantly less visible to predators. In fact, zebras are still frequently hunted by lions, suggesting that if stripes provide any anti-predator advantage, it is probably not their main evolutionary purpose. Another idea proposed that stripes help zebras regulate body temperature.

Black stripes absorb more heat than white ones, potentially creating tiny air currents along the skin that could cool the animal. Some studies have found evidence supporting minor thermoregulatory effects, but the results have been mixed, and the cooling benefits appear insufficient to fully explain why zebras evolved such elaborate patterns.

Thermoregulation may contribute to the usefulness of stripes, but most researchers no longer regard it as the primary explanation. The strongest evidence currently supports the biting-fly hypothesis. Horseflies, tsetse flies, and other biting insects are more than mere annoyances; they can spread dangerous diseases and drain blood from their hosts.

Researchers have repeatedly found that these flies avoid landing on striped surfaces. Experiments involving striped coats placed on horses, painted cattle, and even real zebra skins have consistently shown that biting flies land far less often on striped patterns than on solid-colored ones. Scientists believe the high-contrast stripes

interfere with the insects’ visual systems, making it difficult for them to judge speed, distance, or landing angles. Some theories suggest that the stripes create optical illusions or disrupt how flies perceive polarized light, causing them to abort landings or miss their targets altogether. The geographical distribution of zebra species also supports this explanation. Zebra populations tend to occur in regions where biting flies are especially abundant and disease transmission is a major threat.

maintain social cohesion within herds, or provide modest thermoregulatory benefits. Nature often repurposes traits for several uses over time. Nevertheless, after more than 150 years of scientific debate, the evidence increasingly points to an answer that is both elegant and practical: zebras likely wear