Thursday, March 20, 2008

Gecko Science

Geckos (or is that geckoes?) are amazing creatures. They sell car insurance, and they climb walls and walk on ceilings. Because of these uncanny abilities, scientists have been studying them for quite some time.

The Telegraph (UK) reported January 23, 2008, on the development of "Spidey" gloves based on gecko toes.

Prototype "Spiderman gloves" that will enable window cleaners to scale walls, robots to scurry across ceilings and rock climbers to hang about could be ready within three years.

There has been popular interest in how to mimic his extraordinary wall climbing ability since 1962, when the web-slinging hero with superhuman strength was born in the pages of Marvel Comics.

A Californian team reports today that has got the hang of gecko adhesion and solved the mystery of how the lizards manage to stick without getting stuck, marking a boon for real life Peter Parkers.

While conventional adhesive tape sticks when pressed on a surface, the new gecko-inspired adhesive only adheres when it slides.

Pretty cool. But there's more!

The Telegraph reported on St. Patrick's Day that the gecko's tail is important too.

The gecko's feet have already helped spawn a new generation of dry glues for "Spiderman gloves."

Now the tail of the climbing lizard is providing engineers with the inspiration for more agile robots and may aid in the design of unmanned gliding vehicles or even help astronauts move in space.

In a study published today in the Proceedings of the National Academy of Sciences, the biologists report that geckos rely on their tails to keep from falling off vertical surfaces and, if they do fall, to right themselves in midair and adopt a "Superman" posture, like a skydiver gliding to a safe landing.

According to seniorauthor Prof Robert Full, previous experiments focused on their unique toes as the key to running up a wall and hanging onto ceilings: Prof Full discovered six years ago that, while claws help geckos climb rough surfaces, millions of microscopic toe hairs make it possible for them to climb smooth ones, a finding that has inspired Gecko glue.

But that was not enough. Only when engineers were motivated by these findings to create gecko-like robots, such as Boston Dynamics Inc.'s RiSE (Robot in Scansorial Environment), theUniversity of Pennsylvania's DynaClimber and Stanford University robots Spinybot and Stickybot did they discover that a tail might be necessary to prevent the robot from pitching backward and falling when it slips on a vertical surface.

"They have an active tail that functions like a fifth leg to keep them from tipping backward," says Prof Full. "This is an undiscovered function for tails that tells us a lot about how active tails could affect the performance of vertebrates."

With the help of high-speed video, the researchers discovered that when a gecko loses traction with one leg, it taps its tail on the surface to keep its balance until the toes can grab hold again.

The team also notes that the lizards nearly always made a four-point landing after using their tails to reorient in mid-air. Using high-speed video to record geckos falling upside down from a fake leaf, they found that the geckos rotated their tails so that their bodies counter-rotated to face downward, then spread their legs and toes to parachute.

The lizards, after turning face down, often used their tails to manoeuver in mid-air like a skydiver toward a targeted drop zone. In wind tunnel tests, geckos could actually hover in the air stream and, using their tails, steer toward a solid perch.

The scientists called the gecko's spread-eagle falling pose the "Superman posture." More comic book heroes for the gecko.

I'm not quite sure how the scientists expect astronauts to grow a tail to use in space to keep them from falling. And how do you fall in zero-gravity anyway? That's a mystery they haven't explained to me yet.

All the same, what scientists have learned about these little lizards is astounding. And geckos eat bugs too. What perfect creatures!

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