Decoded: How geckos cling to ceilings
Posted on Aug 13 2014 | IANS
New York, Aug 13 : Are you amazed at how geckos as well as spiders and some insects run up and down walls and cling to ceilings?
Researcher believe they now know how they seemingly defy gravity with such effortless grace.
The toes of geckos use tiny, branched hairs called "seta" that can instantly turn their stickiness on and off, and even "unstick" their feet without using any energy, the findings showed.
These extraordinary hairs contribute to the ability of geckos to run, evade predators, and protect its very life and survival. In essence, a gecko never has a bad hair day.
"These are really fascinating nanoscale systems and forces at work," said Alex Greaney, an assistant professor Oregon State University.
It is based not just on the nature of the "seta" but the canted angles and flexibility they have, and ability to work under a wide range of loading conditions, Greaney explained.
Even more compelling is the minimal amount of energy expended in the whole process, as a gecko can race across a ceiling with millions of little hairy contact points on its feet turning sticky and non-sticky in a precisely integrated process.
This "smart" adhesion system allows them to run at 20 body-lengths per second, and, hanging from a ceiling, the forces provided by the seta could actually support 50 times the body weight of the gecko.
Geckos' feet are by default non-sticky but the stickiness can be activated by a small shear force to produce this surprisingly tough form of adhesion.
The study appeared in the Journal of Applied Physics.