As we inch closer and closer to Halloween by the day, it’s the perfect season to learn more about some of the spooky yet mesmerizing things that lurk in the dark, specifically one particularly creepy group of creatures- flying snakes. Though snakes are one of the most commonly feared animals and something we generally try to avoid even here in Hoboken, there is one particular genus of snakes known as the flying, or gliding snake that possesses some seriously fascinating abilities.
Chrysopelea, better known as gliding snakes, is a genus made up of five species of tree snakes which reside in South East Asia that possess an unmistakably eerie ability to glide through the air. Though the thought of a snake flying towards you might be unsettling, the mechanisms that allow gliding snakes to do so are truly an evolutionary wonder. The aerodynamics of the gliding snake remain a mystery, as relatively few studies have studied them, with creatures like birds, bats, and insects having received most attention from researchers, leaving animals that can only glide, but not fly, heavily ignored.
To perform their unique gliding motion, gliding snakes move from side to side, sending waves with large amplitudes through their bodies. They launch themselves from trees and, upon becoming airborne, begin splaying their ribs and flattening their bodies in the dorsoventral axis to create a rather unconventional cross sectional shape. According to Dr. John J. Socha at Virginia Tech, how a snake, with its ribs spread and body flattened, is able to achieve aerodynamic lift, is truly a mechanical mystery. What makes the gliding snake so slitheringly interesting is its ability to seemingly defy what we know about how most animals interact with aerodynamics. The gliding snake uses a completely different set of mechanisms than other flying animals like birds and insects. The combination of an undulating motion with the paired effects of body morphing that results in the body not exhibiting bilateral symmetry is a phenomenon never seen before in biological nor engineered flyers. From bats to gliding ants, no other species has been identified using this type of mechanism.
In the case of the paradise tree snake, a particular species of gliding snake which Dr. Socha has studied extensively for over a decade, the cross sectional shape of the snake’s body varies along the span of its length. In 2014 Dr. Socha and colleagues analyzed what “type of wing” the snake’s body mimics while in air. After modeling the paradise tree snake’s body, Socha and his team found that the snake moves in the air exactly as it would in the land or the water, in an “S” shape. “It doesn’t straighten out and fly like a living javelin,” says Dan Holden, one of Dr. Socha’s colleagues, “It more or less works its way through the air like the wiggly pipe that it is, with much of its body… always broadside to the air flowing over it”. The team immersed the model in a tank, using water to mimic air flow over the snake. They found that at angles between 15 and 45 degrees, the snake actually achieved better lift than that of many conventional wing shapes.
However, Holden and Dr. Socha’s work thus far is only the beginning. To truly understand the aerodynamics at work, the paradise snake’s subtle changes in movement while in the “S” shape must be modeled at each fraction of a second.
As ducks, another incredibly well engineered animal, we know that the biomechanical properties of many birds and insects’ bodies are used to model planes and robots. It’s possible flying snakes have a future in engineering too.
