Geckos are among the fastest and most versatile climbers in nature -- they can scale vertically and walk unperturbed upside down -- but it's taken scientists several experiments over several years to figure out how to duplicate and improve on their super-human properties so we can climb like geckos too.
One secret to their climbing powers is their feet -- their four toes, unlike our five, can curl both forward and backward, which lets them quickly peel away from a surface as they run up it.
Also, according to U.C. Berkeley biologist Robert Full, the bottoms of geckos' toes are covered with millions of tiny hairs -- each hair in turn with 100 to 1,000 split ends -- which creates a powerful "dry adhesive" that lets geckos climb without falling by using the natural force (i.e. the van der Waals force) that binds molecules together.
Finally, geckos use their long tails to balance, help support their weight or steer when they leap or fall, Full found. Geckos that are shaken loose from tree branches use their tails to right themselves as they fall, just as cats do.
Full has been working with scientists from Stanford, Carnegie Mellon, SRI, the University of Akron, Boston Dynamics and other places to design gecko-robots, which have several practical applications -- they could scale the outside of the International Space Station with equipment, for instance, or check for survivors after disasters. DARPA is interested in these robots.
Stanford released a video last week of Stickybot, its latest iteration of a gecko-robot which scales walls with the help of 19 tiny separate motors. Scientists at Stanford and the University of Akron, meanwhile, have figured out how to duplicate geckos' toe hairs by building carbon nanotubes, creating a material that is even stronger than gecko hairs -- it's strong enough to support humans who scale walls.
An interesting video for gecko newbies, though, is the talk on geckos and robots (see below) that Full gave at TED last year.
Full has spent years studying animals to figure out how humans can improve on what they do by combining scientific disciplines.
"If you try to copy nature, you make a lot of mistakes," he told Berkeley's news service back in 2002. "Nature is complicated and has a lot of history, and if you try to copy it blindly you don't do very well. You need to be inspired by nature and extract the general principles and combine that with principles of engineering -- then you can improve on nature."
Here's how he's improved on gecko climbing so far: