Geckos Use Tail for Acrobatics

March 18, 2008 -- Geckos are among the world's most talented acrobats, and now researchers know how these bright green lizards perform stuntman-type feats, such as climbing up slippery vertical surfaces, gliding and falling as if they're wearing a parachute.

The secret behind a gecko's gymnastics is literally at its behind; it's their tails.

Gecko tails allow for so many impressive moves that scientists are now contemplating outfitting future astronauts with robotic tails modeled on those of the chirping lizards.

"In emergency situations where thrusters or gyroscopic devices fail, a thin rod extending like a telescope with a sufficient ballast attached to its end could provide effective attitude control for any body in space," explained Ardian Jusufi, lead author of the study, which is published in this week's Proceedings of the National Academy of Sciences.

"An actuated robotic tail could be a more comfortable way for astronauts to control their body movements," added Jusufi, a University of California at Berkeley biologist.

For the study, he and colleagues Daniel Goldman, Shai Revzen and Robert Full put several geckos through obstacle courses designed to mimic the treacherous environments wild geckos must regularly navigate, like walking up slippery plant stems or traversing brittle tree bark from high levels.

Video footage of the elite lizard climbers revealed that under the best conditions, geckos grab onto surfaces with hairy toes that uncurl and peel within milliseconds. If they hit a slippery patch, their tails go into action.

"During rapid climbing, the tail functions like an emergency fifth leg," Jusufi told Discovery News. "If they slip with a front foot, the tail taps the wall and stops their heads from tipping backward. If this response is not enough, the geckos use their tail as a bicycle kickstand against the wall to stop them from falling head-over-heels."