Researchers Find Secret behind Gecko's Clinging Ability

The gecko's ability to stick on leaves and twigs during heavy rain has always fascinated researchers studying the lizards. The study on geckos has brought scientists a step closer to develop an adhesive that can stick under water.

Geckos belong to the family Gekkonidae, which contains over a 100 genera and 1,000 species. Most gecko species are 3 to 15 cm (1.2 to 6 inches) long, with their tails accounting for roughly half of their length. Geckos are known to climb and even run on smooth surfaces using their toe pads that are covered with hair-like projections.

Previous studies have shown that geckos hold on to surfaces with their toe pads that have short, clingy hairs. However, the geckos can't hold on to wet glass. This led the current study team find out how geckos manage to stick on wet trees during rains.

For the study, six geckos were attached with a harness. The harness was then tugged gently as the reptiles tried to stick to various surfaces in dry or wet conditions.

According to the study, geckos' ability to stick to a surface depends on the surfaces' wettability. Higher affinity between water and surface means lower adhesion between geckos toes and the surface, for example a wet glass where a film of water prevents the gecko's feet from clinging to the surface.

Meanwhile, surfaces that have low wettability such as waxed leaves or twigs (that are water repellent) are ideal surfaces for the geckos.

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

The study is published in the journal Proceedings of the National Academy of Sciences.