Researchers Uncover Mystery on how Geckos Stick to Wet Leaves

For many years, researchers have been fascinated with the ability of geckos to maintain a grip on trees and leaves in their wet natural habitats.  But not much was known about how these reptiles managed to cling on to wet surfaces.

A team of scientists from the University of Akron has uncovered the mystery behind how geckos manage to cling on to wet surfaces. The scientists have discovered that leaves and tree trunks have wet hydrophobic surfaces that secure a gecko's grip in a similar manner as that of a dry surface.

The scientists focused on the gecko's pads, which have adhesive qualities. The pads have tiny clingy hair that sticks like glue to dry surfaces. Prior to this, the team had conducted a study in 2012 where they claimed that geckos struggle to maintain a grip on wet surfaces. This made them focus on how lizards manage to function in their natural environment.

In order to examine the gecko's ability to maintain a grip, the scientists put harnesses on six geckos and placed them on four different surfaces that differed in the degree of water resistance or wettability.

They noticed a link between the effect of water on adhesive strength and the wettability. On glass that had high wettability, there was a decrease in adhesion. On low wettability surfaces such as waxy leaves and on tropical plants, the geckos' toes were dry and maintained firm adhesion.

"The geckos stuck just as well under water as they did on a dry surface, as long as the surface was hydrophobic," Alyssa Stark, UA integrated bioscience doctoral candidate, explains. "We believe this is how geckos stick to wet leaves and tree trunks in their natural environment.

The study was published April 1, 2013, by the Proceedings of the National Academy of Science.