Geckos Can Control the Movement of Their Toe Hairs

Geckos take advantage of van der Waals forces to run across ceilings, but a simple shift allows them to drop to the ground

Photo: DK Limited/Corbis

Researchers have been unraveling the mystery of gecko toes for years, hoping those cute reptiles will lend a few clues for designing better adhesives and glues. Several years ago, scientists discovered how the nimble lizards manage to sprint across ceilings. As it turns out, they use van der Waals forces—light attractive forces between molecules—to stay in place. 

As exceptional escape artists, however, geckos will oftentimes leap from surfaces to evade a predator (or a lumbering human hand trying to trap them). How they manage to quickly break the force holding them to surfaces has remained a mystery, National Geographic reports. Now, new research answers that question: they manipulate the angle of their toe hairs. 

Gecko toes contain thousands and thousands of tiny hair-like structures. As NOVA Next describes

If you manage to catch one of these nimble lizards and take a closer look at its toes, you’ll see a plethora of thin ridges, almost like a tightly packed file drawer. Take an even closer look—at about 700 times magnification—and the ridges blossom into a thick rug of forest-like tubes. Even closer, at about 30,000 times, and you’ll notice that each of these tubes are covered with 100 to 1,000 nanoscale split ends. There are around 2 billion of these microscopic tendrils on every gecko.

Researchers from Oregon State University created a computer model of the lizards' toes, National Geographic reports. They found that a simple shift in the angle of the hair would, in theory, break the adhesive bond that keeps geckos attached to the wall. The hairs' curved structures, they also found, act like a "spring-loaded detachment mechanism,” as one researcher described to National Geographic

So the next generation of gecko-inspired robots, National Geographic adds, might not only be able to climb up vertical walls, but also fire themselves off those surfaces by a simple twitch of their toes. 

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