Gecko!
A flat-tailed house gecko skydiving
In an experiment that could only have come out of California, UC Berkeley researchers decided to see what would happen if they chucked a gecko into a wind tunnel. Who says science can’t be fun?
Looking for inspiration for building more maneuverable robots, the researchers pointed a powerful fan straight up to simulate freefall conditions and used a high-speed camera to watch the gecko’s in-flight acrobatics.
What they discovered is that the gecko hardly moves its feet at all in the air. Instead, it uses its fat-filled tail to control its pitch and yaw, which leaves its bulbous toes to act as drag shoots! In this way the gecko was able to precisely navigate its way to a perch at the bottom.
With all the leaping around they do geckos need to be sure-footed to survive, so it helps that their feet are stickier than our strongest super glue. Every square millimeter of their footpads contains about 14,000 superfine hair-like structures, and each one of them is tipped with between 100 and 1000 even finer bristles (see second photo). The gecko is able to tap into powerful electrostatic forces that surge in the narrow gaps between the hairs. It’s these van der Waals forces that lend the gecko’s feet their near-supernatural tackiness. So forget nails, the mathematics of these forces indicates that — and we stress that this is purely speculation — a full-sized gecko on your ceiling could support the weight of a 290-pound chandelier!
Every square millimeter of gecko footpads contain about 14,000 superfine hair-like structures.
Credit: Robert Full/UC Berkeley, copyright PNAS/NAS 2008
Original photo caption: This photo of a flat-tailed house gecko skydiving in a wind tunnel was selected for the cover of the March 18, 2008, issue of PNAS. Geckos use their fat-filled tail to right themselves in midair and maneuver to a secure perch.
Tags: electrostatic, gecko, mathematics, van der Waals forces
