Geckos are renowned for their sticky toes and eyeball-licking tongues, but a nifty new trick has been added to the list: small spinules that make water droplets “pop off” their skin like popcorn.
Similar abilities can be seen on some insects, but it is a recent discovery for these lizards, which in this case is the box-patterned geckos (Lucasium steindachneri). Scientists have dubbed the phenomenon “geckovescence,” and published the study in the Journal of the Royal Society Interface.
To study the multi-talented creatures in finer detail, researchers from the University of the Sunshine Coast in Queensland, Australia, used a scanning electron microscope to examine tiny spinule structures on the geckos’ skin. The team found that the tiny spines trap pockets of air, which discourages dewdrops from trickling into open spaces and spreading out as a thin layer the lizard's skin. Instead, the drops merge together, growing larger and larger until natural forces such as wind or gravity take over to drive the water off.
But here’s the best part: If a tiny droplet lands on a large one, it pops the big droplet off the skin like popcorn. And it's possible for droplets with diameters between 10 to 80 micrometers to self-propel themselves off.
“When two droplets unite, their volume stays the same but their combined surface area—and thus, their surface energy—goes down,” National Geographic explains. “They convert some of that surface energy into kinetic energy, and if the trade-off is substantial enough, they can launch themselves into the air."
The scientists say this ability may help geckos reduce the amount microbial content on their skin, which is important in a humid environment where fungi and bacteria thrive.
According to researcher Jolanta Watson, they "are now focusing on other interesting properties of the skin nanostructuring which, combined with the jumping droplets phenomena, may find applications in the health and other materials industries.”
Watch the slow-motion video by New Scientist below: