Zebras, with their striking black and white patterns, are among the most recognizable animals on the African plains. Their distinctive appearance often sparks a common question: Is a zebra white with black stripes, or black with white stripes? This curiosity extends beyond their color to the purpose of their unique markings, which have fascinated scientists for centuries. Unraveling their stripes reveals intriguing biological processes and evolutionary adaptations.
Zebra’s True Base Color
Zebras are fundamentally black animals adorned with white stripes. Their skin, uniformly black beneath their fur, confirms this primary color. The appearance of white stripes occurs where the production of pigment is actively inhibited.
The black coloration comes from eumelanin, a pigment produced by specialized cells called melanocytes. These cells are present across the zebra’s skin, determining the color of the hair that grows from hair follicles. White stripes are areas where these melanocytes are “turned off,” meaning they do not produce pigment for the hair.
How Stripes Develop
A zebra’s intricate stripe pattern is determined during the animal’s embryonic development. This process involves melanocytes, the pigment-producing cells distributed across the developing skin. During development, melanocytes become active in some areas to produce black stripes, while their activity is inhibited in others, resulting in white stripes. This pattern formation is thought to involve a reaction-diffusion process, where chemical signals during fetal development influence the distribution and activation of pigment cells. Although foals are born with stripes, their initial brown and white patterns gradually darken as they mature, typically transitioning to the characteristic black and white between 9 and 18 months of age.
Why Zebras Have Stripes
Several compelling theories explain the evolutionary reasons behind zebra stripes.
One theory suggests stripes deter biting insects, such as tsetse flies and horseflies. The striped pattern confuses these insects, making it difficult for them to land, which reduces bites and disease transmission.
Another theory suggests stripes assist with thermoregulation in the hot African climate. Black stripes absorb more solar radiation and become warmer than white stripes, which reflect light. This temperature difference may create small convection currents that help dissipate heat from the zebra’s body, aiding cooling through enhanced sweat evaporation.
Stripes may also offer a form of camouflage, particularly when zebras move in a herd. This “motion dazzle” effect can confuse predators, making it challenging to single out an individual or accurately judge their speed and direction. Each zebra also possesses a unique stripe pattern, much like a human fingerprint, which may facilitate individual recognition within a herd, strengthening social bonds and aiding mother-foal identification.