The California King Snake slithers effortlessly across the terrain, thanks to its well-lubricated slippery scales. And the unique structure of those scales may help scientists devise new kinds of water-resistant paints, coatings, or plastics, or design better snake-like robots.
That's the conclusion of researchers from Oregon State University and Germany, who wanted to know why the snake's underbelly is more slippery, with far less friction, than its spine -- despite the fact that the scales themselves are the same size and shape all over, even when viewed under a microscope. They also have a similar thin layer of fatty lipids covering them.
It's those lipid molecules that hold the key to the differences in slipperiness, according to OSU's Joe Baio, who led the project as part of a larger collaboration to investigate the structure of snake scales across many different species. The team presented their results earlier this month at a meeting of the American Vacuum Society in San Jose, CA.
Baio and his collaborators used a scanning electron microscope combined with spectroscopy to examine the scales on the king snake's underbelly. That analysis showed lipid molecules lining up in regular rows and columns, perpendicular to the scales. This, apparently, is why the outer lipid later is so tough. It acts like the nylon layer of a down jacket, preventing friction-inducing particles from touching the underlying skin, while still being flexible enough not to break.
The scales on a snake's back are thicker, but have a thinner lipid layer, and thus are less able to switch from soft to swift. "The back scales are mainly there to prevent reflections, and provide camouflage, rather than help with movement," collaborator Stanislav Gorb, a biomechanics student at University of Kiel in Germany, told Inside Science News Service.
You can't feel those subtle differences with your bare hands, but they are there, nonetheless. And those slight changes in structure could lead to extra-slippery paints and coatings, the next generation of engines, or robotic snakes designed to worm their way into tight spaces -- say, a collapsed building that may be trapping survivors of an earthquake.
"Anything that is sliding needs to reduce friction," said Gorb. And the California King Snake is a master of that.
Image: Spacecadet via flickr.