Geckos have an amazing ability to climb walls. They can climb vertically up a glass window. They can walk upside down on a shiny steel surface or even Teflon. How do they do it?

Scientists can’t agree on how the gecko’s sticky feet work, even though they have studied these lizards for years. In 1934 a German scientist suggested that the secret is electrostatic forces. He used X-rays to ionize the air around the gecko’s feet to neutralize static charges. The gecko still stuck to the wall. That experiment seemed to rule out electrostatic charges to explain the lizard’s wall-climbing ability.

A more recent study reported in 2000 suggested that the secret is an interaction between atoms called van der Waals forces. Geckos have microscopic hairs on the pads of their feet (called setae), and the research seemed to indicate that atoms in the setae attract the atoms of the material the gecko is climbing.

In 2014 a new study by a Yale engineer showed that geckos have twice the gripping power on Teflon as on silicone rubber. If van der Walls forces explained the attraction, it should be the same on both surfaces. He found that electrons jumped from the setae to the surface creating an electrostatic charge. So electrostatic force is the answer after all.

But wait a minute! A gecko can stick to bare metal where electrostatic charges can’t accumulate. So it looks like geckos use more than one technique to perform their apparent magic. Brilliant scientists have spent years analyzing the amazing ability of these fascinating creatures. Maybe someday they will figure out what God did in this “dandy design.”
© Roland Earnst

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