Zebras: It’s in the Stripes

Ever wonder why zebras have that characteristic black-and-white pattern?

A combined research team representing universities in both Hungary and Sweden was interested in this very question. In a March 2012 paper in the Journal of Experimental Biology, the researchers published the results of their findings. Turns out, zebras don’t like being bitten by horseflies (who does, really?) The pattern on zebras (the alternating black and white stripes) creates a multi-directional array of polarized light, decreasing the attractiveness to horseflies, which prefer linear polarized light. In fact, the width of stripes falls within a special range that makes zebras most disruptive to horseflies. Since zebras live in Africa, where these flies are everywhere, this adaptation is quite helpful. A horsefly bite can have severe effects on reproductive health.

It should be mentioned that another strong hypothesis for stripes on a zebra has to do with the power of the herd. With so many striped zebras standing or running together, it is difficult for a predator to pick out just one individual to target for a meal. A lion can’t tell where one zebra ends and the other begins. Often times, one adaptation serves as a solution to multiple problems. This could very well be the case here with the zebra – both predator and parasite protection.

Bioinspiration, or biomimicry, is the methodology in which biological systems, processes, or elements are studied to draw analogies to be applied to human design challenges in a sustainable manner. Think about the human population of Africa: people are subject to the pesky biting horseflies, too. Wearing clothing patterned in a similar fashion as the zebra, or outfitting a home exterior with zebra stripes, could help keep them horsefly-free.

Applications of this innovation extend beyond humans, too. In this year’s design competition for San Diego middle school students, Emily Canizalez from Challenger Middle School invented a zebra-inspired, pest-deterring blanket for dogs. Animal print is not just fashionable—it’s also functional. But please, keep it faux!

Dena Emmerson is a biomimicry research assistant at the San Diego Zoo. Read her previous post, Cockroach Improves Search and Rescue Robots.

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