Most snakes move by bending their bodies into S-shapes slithering forward with their heads first. But sidewinder snakes that are usually found in the deserts of Africa, the Middle East, and North America move with their mid-sections first instead of their heads, slithering sideways across the loose sand.
According to the Smithsonian Magazine, sidewinder snakes at a speed of 18 miles per hour, making it the world's fasted snake.
A recent study by physics professor Dr. Jennifer Rieser of Emory University in Atlanta and colleagues found that the secret of these snakes' sidewinding movement is hidden underneath their skin: their scales that are packed with tiny pits instead of spikes like most snakes.
They published their study on February 1 in the journal Proceedings of the National Academy of Sciences.
Microscopic Spikes Help Snakes Move
According to The New York Times, sidewinder snakes have scales instead of spikes underneath their skin. These microstructures help snakes move as they are limbless animals, unlike other species.
The researchers used an atomic force microscope to investigate the naturally shed skins of sidewinder skins and built mathematical models to test how the structures they observed in the skin could help sidewinder snakes move on different surfaces.
Although the scales beneath the snakes' skin may appear smooth with the naked eye, the researchers found that the belly scales have microscopic spikes that create friction between their body and the ground, which helps them move forward in a headfirst manner.
However, it seems that sidewinder snakes have either reduced or phased out those spikes, preferring instead the belly scales that are pocked with microscopic pits that can move in any direction.
Why Do Sidewinder Snakes Do Not Have Spikes
Dr. Rieser thinks that this change is because it is harder to move friction in a frictionless environment. According to Phys.org, the researchers' mathematical model showed that head-to-toe spikes could enhance forward undulation speed and distance, but it could be detrimental sidewinding.
Moreover, the round pits' non-directional structure in scales enhanced the sidewinding movement of the sidewinder snakes but not as efficient as the spikes for forward movement.
The researchers also believed that the microscopic pits were a result of evolution. They said that different species evolve similar traits as a result of having to adapt to their environment.
For example, the Saharan horned viper and the Namib desert's sidewinding adder both have scaly bellies with uniform pits but without any spikes. However, sidewinding rattlesnakes that come from the viper family tree have pits and vestigial belly spikes.
"That may explain why the sidewinder rattlesnake still has a few micro spikes left on its belly," Rieser said. "It has not had as much time to evolve specialized locomotion for a sandy environment as the two African species, that have already lost all of their spikes."
She said that engineers could use their findings in designing their robots by considering the type of surface they need the robot to move on. Designing a robot to a particular surface could help enhance its movement.
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