Most snakes get from A to B by bending the bodies to S-shapes and moving forward with a head. A few species, however – found in the deserts of North America, Africa and the Middle East – have a strange way of getting around. Called “sidewinders,” these snakes go with their middle sections instead of their heads, sliding sideways over loose sand.
Scientists took a microscopic look at the skin of a lateral to see if it played a part in their particular mode of movement. They found that the bells of sidewinders are full of tiny pits and that there are few, if any, of the tiny spikes found on the bells of other snakes.
The Proceedings of the National Academy of Sciences he published the discovery, which involves a mathematical model linking these specific structures to action.
“The specialized movement of sidewinding has grown exponentially in different genres in different parts of the world, suggesting that sidewinding is a good solution to a problem,” says Jennifer Rieser, professor of physics at Emory University and the first author of the study. “Understanding how and why this example of homogenous evolution works allows us to adapt to our own needs, such as building robots that can move in challenging environments. “
Co-authors of the paper include Joseph Mendelson, botanist and study director at Zoo Atlanta; evolutionary biologist Jessica Tingle (University of California, Riverside); and physics Daniel Goldman (Georgia Tech) and co-first author of Tai-De Li (New York City University).
Rieser’s research interests combine the physics of soft materials – accessible materials such as sand – and organic biology. She explores how animal surfaces interact with the flowing materials in their environments to get around. Insights from her research could lead to advances in human technology.
Snakes, and other endless locomotives, are of particular interest to Rieser. “Although snakes have a very simple body plan, they are able to successfully manage a number of habitats,” she says. Their long, flexible bodies encourage work on ‘snake’ robots for its own use. -everything from surgical procedures to search and rescue missions in collapsed buildings, she said.
In a previous paper, Rieser and his colleagues found that robot design could move in serpentine ways to help them avoid a catastrophe when they collide with objects in their path.
Sidewinders allowed her to dig further into how nature has changed ways of moving over loose sand and other soft material.
Most snakes usually keep their bellies in contact with the ground as they slide forward, bending their bodies from their heads to their tails. A sidewinder, however, lifts its midsection off the ground, moving it sideways.
Previous studies have suggested that sidewalls may allow snake movement on sandy slopes better. “Sideways are thought to be spreading the forces their bodies exert on the ground as they move so as not to cause a sand dune as they move across it, “Rieser explains.
For the mainstream paper, Rieser and her colleagues explored whether sidewinders skin could play a role in their unique movement style.
They targeted three species of sidewinder, all pipers, living at zoos: The sidewinder rattlesnake (Crotalus cerastes), found in the deserts of the Southwestern United States and northern Mexico; and the Saharan horned viper (Cerastes cerastes) and the Sahara sand viper (Cerastes vipera), both from the deserts of northern Africa.
A skin shed from the side arrays was collected and scanned with an atomic force microscope, a method that provides a solution at the atomic level, on the order of nanometer fractions. For comparison, they would also scan snake skin skins from people who were not side by side.
As expected, the microscope revealed tiny spikes head-to-tail on the skin of those who did not side. Previous research had identified these micro-spikes on several other sliding snakes.
The current study, however, found that the skin of sidewinders is different. Both African sides had micro-pits inside and without spikes. The skin of the rattlesnake sidewinder was also full of tiny slits, along with a few, much smaller spikes – though far fewer spikes than the skin of slippery snakes.
The researchers created a mathematical model to test how these different structures affect surface-fracture interactions. The model showed that head-to-tail point spikes increase the speed and velocity of forward movement but do damage to sidewalls.
“You can think of it as the ridges of corduroy material,” Rieser says. “When you run your fingers across a corduroy in the same direction as the ridges there is less frost than when you slide your fingers over the ridges.”
The model also showed that the uniform, non-directional structure of the circular grooves strengthened sidewalls, but was not as effective as spikes for forward rotation.
The research provides small images at different times during homosexual evolution – when different species independently change similar traits as a result of adapting to similar environments.
Rieser notes that America’s sandy deserts are much younger than those in Africa. North American Mojave collected sand about 20,000 years ago while sand conditions appeared in the Sahara region at least seven million years ago.
“Maybe that explains why there are still a few micro-spikes left in the womb,” she says. “It hasn’t taken so long to develop specific locomotives for a sandy environment than the two African species, which have lost their spikes.”
Engineers may also want to change their robot designs accordingly, Rieser adds. “Depending on what type of surface you need a robot to move forward,” she says, “you may want to consider designing its surface to have a specific texture to promote its movement. ”
###