Geckos living in areas with little rain but where there is lots of humidity are able to maintain dry skin. This is due to microscopic hairs that corral water drops and expel them from the surface.
A science team based at the University of the Sunshine Coast, James Cook University, the University of Queensland in Australia, and the University of Oxford, have joined forces to examine the skin of ground-dwelling box-patterned geckos (Lucasium steindachneri). The research was performed with the use of a scanning electron microscope.
By taking electron micrographs, New Scientist reports that the researchers discovered that the skin was covered in densely packed spiny hairs, each a few micrometers in length. By trapping pockets of air, the spines force water on the skin’s surface to remain as spherical droplets rather than spreading in an even layer over the reptile’s scales. A typical water droplet makes contact with around 100,000 spines.
Having made this discovery, the researchers went onto study slow-motion videos to examine how the spiny scales repelled water. They found that the skin’s structure encourages the water drops to merge, creating a larger drop that eventually falls off the skin due to gravity, wind, or being hit with a smaller falling droplet that drives it from the surface at high speed. The narrow spines cause the merging drops to convert the energy associated with their shrinking surface area into kinetic energy that sends them flying off the animal’s skin.
Interestingly, getting rid of water droplets that could host pathogenic bacteria and fungi may help the geckos prevent disease.
The research has been published in the Journal of the Royal Society Interface. The research is called “Removal mechanisms of dew via self-propulsion off the gecko skin.”
