As a biomechanist, Socha works at the intersection of biology and physics, studying flying snakes for almost 20 years. He noticed that so much was known about how birds fly, but so little work had been done on serpent flight despite the creature first being recognized in the late 1800s.
"Most of the early writing was natural history-type notes, where some British scientist in Southeast Asia happens to see one go through his tea garden," Socha said. "'I tried to whack it with a stick and missed it!'"
The glide starts with a small jump, after which the snake extends itself out to full-body length. It gains speed as it sharply drops; then mid-flight, its ribs splay apart and cause the normally circular body to flatten. It makes an S-shape and starts to undulate. Eventually, the flight path becomes more horizontal as it glides forward.
In earlier experiments, Socha filmed snakes diving off tree branches using multiple cameras positioned at different angles in order to capture an accurate description of their geometry during flight. Using that data, he created an idealized 3-D model of the snake's flattened body, which formed the basis for Barba's computer simulations and his physical fluid-flow model.
"These shapes are very efficient at generating lift when they are positioned at high angles of attack," Barba said, referring to the angle of the flat surface with respect to the body's trajectory in the air. "Normally, an airplane wing operates at very low angles."
Socha has found that serpents tend to maintain angles of attack of about 20 to 40 degrees. Also, some portions of the snake's body are perpendicular to the trajectory they are moving in, so they become like little sections of a wing. They hit the wind sideways, allowing for more lift.