Jake Socha is a flying snake expert who uses detailed scientific terminology, such as “this big wavy thing” to describe his great quarry.
It is an adequate description, but do not be fooled. When a snake jumps out of a tree into its Southeast Asian habitat and lands on another tree dozens of feet away, there’s nothing random about those wiggles.
Professor of biomedical and mechanical engineering at Virginia Tech, Dr. Socha and colleagues published a study Monday in Nature Physics that supports the hypothesis that air ripples (wiggles) are truly coordinated and highly functional processes that improve stability. Dynamic of The Serpent in Flight.
“I wouldn’t say that all the mysteries are solved,” said Dr. Socha, “but we have a large part of the story completed.”
Flying is a little inappropriate for what snakes do. Gliding creatures in midair tend to strategically drop or glide, meaning they don’t gain altitude like a bird or insect. Their flights generally last only a couple of seconds, at a speed of around 25 miles per hour, and they land without injury. To the inexperienced eye, it might appear that the snake fell from a tree by accident, moving frantically as it plummets to the ground. Not so.
Once it rises into the air, after slowly advancing on a tree branch and pushing on the branch, the snake moves its ribs and muscles to extend the width of its underside, transforming its body into a structure that redirects the flow air like a parachute or a wing. A cross section of the snake’s body in midair would show that its normal circular shape becomes triangular and the entire body undulates as it glides toward its target.
Once in Singapore, Dr. Socha and a group of researchers witnessed a snake jump from 30 feet high and travel more than 60 feet in the air on a windless day.
“It was like an athlete accelerating,” he said. “It was like, ‘I know what I’m doing, I’m leaving, and you’ll never see me again.'”
For years, Dr. Socha wondered if ripples were functional for flight or if snakes simply repeated the same movement in the air that they use to move through land and through water.
Researchers, including Isaac Yeaton, a mechanical engineering doctoral candidate, carried around half a dozen flying snakes to a four-story black box cube on the Virginia Tech campus. The cube, which can be used for student projects and experiments in arts, sciences and engineering, it is equipped with a high-speed motion capture camera system. The researchers attached infrared reflective tape to the snakes and designed a tall tower with a launching branch and a lower tower disguised as a tree for a landing site. Then they let the snakes fly.
Yeaton, who was once shocked when one of the snakes landed in his arms while standing on the ground, said they observed more than 150 flights of Chrysopelea paradisi, one of five types of flying snakes, during a week in 2015.
“It is hard to believe that a snake can do this,” said Yeaton. “It gives a little scary. But there are a lot of intricate things that are happening. “
The researchers collected the data and then created three-dimensional computer models to show each angle of the snake in flight.
The models illustrate that the undulations contain vertical and horizontal waves. And the waves flow proportionally, with vertical waves twice the frequency of horizontal waves.
They also found that the snake’s rear end moved up and down vertically along what they called the dorsoventral axis, increasing its pitch stability up and down.
“Other animals ripple for propulsion,” said Yeaton. “We showed that flying snakes undulate for stability.”
Using the computer models, the researchers could also remove some or all of the ripples for comparison. Without them, the snake falls randomly and dangerously, like a Frisbee that launches without turning.
The study information, the researchers said, could have applications for robotics, particularly search and rescue. Because, as Dr. Socha might say, wavy things are good for getting into tight spaces, like through the rubble of an earthquake. And they could fly from one rescue site to another.
“I hope that before the end of my life we have a search and rescue robot based on flying snakes,” he said.
