Geckos ‘sticky’ Situation

A research is being conducted on how lizards stick to any surface despite not using sticky secretions to help them hang on. Biologist at university of Calgary is carrying out this research works.

“Unlike most creatures, geckos don’t use sticky secretions to help them hang on, it’s all due to the structure of their amazing skin,” says professor Anthony Russell, one of the world’s leading experts on the gecko family of lizards.

“Figuring out how they are able to run across ceilings and walk up windows is remarkably complex but it is getting a lot of attention because of the possible technology it could yield,” he adds.

He has revealed the latest developments in gekkotan adhesive research, which he made while working with graduate student Megan Johnson, in a paper published in the Canadian Journal of Zoology.

It is one of the only studies to look at how a gecko’s unique toe pads enable it to move through its natural habitat.

“Almost all of the research that has been done has looked at how geckos can walk on glass and other smooth surfaces, but of course their feet evolved for moving over very different surfaces, Russell said.

“By looking at how they climb up rocks and other natural surfaces we are hoping to gain an even better understanding of their adhesive system because coping with rough and unpredictable terrain poses quite different problems than does smooth and even ones. This calls for examining both the animals and the terrain they use at the microscopic level,” he added.

The researcher has revealed that unlike tree frogs and many insects that use some form glue-like fluid to get a grip, geckos are dry danglers. He says that geckos’ fan-shaped, highly flexible feet enable them to get traction on a wide range of surfaces while moving or standing, either up, down, or upside down.

This gravity-defying power lies in the tens to hundreds of thousands of hair-like structures, known as setae, on geckos’ toe pads, adds Russell.

Previous studies had shown that the large surface area of setae allowed the animals to take advantage of molecular-level attraction called van der Waals forces to stick to virtually any surface. It was also suggested that friction was also involved, and that the animals used a whole bag of tricks to help them adjust to circumstances from moment to moment.

In their latest study, Russell and Johnson looked at the rocky habitat of a southern African species of gecko. They found that the setae likely evolved to give geckos traction on rugged surfaces, since only a small area of each toe pad might be able to find purchase in order to maintain grip.

“It’s kind of like the tire of a car. You have a large area of tread but at any moment in time, there’s only a tiny portion that is actually in contact with the road, and you are depending on that to do the job in a variety of circumstances,” Russell says.

Researchers around the world are trying to make the first synthetic “gecko glue”, and the US military is leading the way in trying to create gecko-inspired robots that can scale any surface.

“The goal is to create a completely dry adhesive that doesn’t leave any residue behind and will remain attached as long as you apply a load to it and can be re-used an unlimited number of times. Once we conquer how it works it could be reasonably cheap to manufacture and the possible uses are endless,” Russell said.

According to him, learning from how species are designed by nature to deal with environmental challenges provides key lessons for human innovations.

“This nano-technology has been around for over 50 million years and we are only just beginning to understand how it works,” he said.

Source-ANI
KAR/M