If you look closely, physics can be found governing almost everything in our planet, even biological processes. The way an animal moves, adapts, evolves is mostly dependent on the area they inhabit. Take the sidewinder snake for example. Most snakes slither on the ground in a straight line, often curving as they slide, but their direction is straight. However, as its name suggests, the sidewinder snake moves sideways, something physics professor Jennifer Rieser says is because of its sandy home.
“As we know from trying to move on the sand in a beach or other places, it can be difficult to move on these materials that yield underneath you as you move forward,” she says. She called the movement of sidewinders “an art.” With its unique movement, it can travel up to 18 miles per hour which makes it the fastest snake in the world. But how does the snake manage this?
In her new study, Rieser thinks the secret lies in their scales. In regular snakes, there are minuscule spikes on their bottom, whereas in sidewinder, they have tiny pits. “The microstructure of snake bellies is important to how they move, because that’s how limbless animals interact with the ground,” she said.
Her team gathered sheds of the snakeskin from zoos and examined them under an atomic force microscope. Then they created mathematical models to analyse “how the structures they saw would perform under different kinds of friction.” The friction in most snakes is caused by the spikes, as mentioned earlier. They found similar structures in close relatives of sidewinder rattlesnakes like cottonmouths or diamondback rattlesnakes.
But she believes sidewinders have “either reduced or phased out those spikes.” Instead, these snakes have microscopic pits that have the ability to move in any direction. This is because in a frictionless environment, the directional friction function would make movement much harder. Instead of sliding smoothly, the sidewinder basically lifts chunks of their body into the air. By pulling and pushing in this manner, they navigate through the sandy grounds.
If you want to have a look at how they move, here’s a sample:
“If scale friction is uniform in all directions, it makes sidewinding significantly easier,” said Dr Rieser. However, she discovered that these snakes still have vestigial belly spikes as well as pits, a leftover from their life before they evolved to adapt.