How Snakes Fly UFO-Style

By Charles Q. Choi

Snakes don’t need to be on a plane to fly: Five species of the gliding reptiles can soar as far as 100 feet (30 meters) in the tropical rain forests of Southeast Asia.

Now scientists have discovered the secret behind how these snakes stay airborne—they twist their bodies into an S shape that resembles an alien’s flying saucer from the side.

A flying paradise tree snake glides in Singapore in 1997. Photograph courtesy Jake Socha.

Scientists already knew that flying snakes climb up trees by using ridges on their belly scales to help grip bark as they slither upward, and that when the animals glide downward, they undulate from side to side. (Related: “How Snakes Can ‘Fly.'”)

These movements—done by flexing the ribs—transform the serpent’s body into a totally aerodynamic surface, according to biomechanist Jake Socha, of Virginia Polytechnic Institute and State University in Blacksburg, and his colleagues.

As frightening as the idea of a 4-foot (1.2-meter) flying snake might be to some, these mildly venomous reptiles are harmful only to small prey.

Scientists don’t know how often or exactly why flying snakes fly, but it’s likely they use their aerobatics to escape predators, to move from tree to tree without having to descend to the forest floor, and possibly even to hunt prey.

Watch a video of a flying snake.

Clues From 3-D Printing

To learn more about the aerodynamic forces the snakes generate, Socha and his colleagues used a 3-D printer, which works by depositing layers on top of layers to create 3-D objects. (Related: “Improving 3-D Printing by Copying Nature.”)

The researchers printed a 3-D rod with a UFO-like cross section that mimicked the body of the paradise tree snake (Chrysopelea paradisi), the most proficient snake glider. The team then placed the rod within a tank of water that flowed over it, re-creating the air conditions the reptiles experience as they glide through the forest.

The scientists tilted the rod at various angles as water flowed over it at different speeds, and measured how the current moved the rod up or down.

The results, published January 29 in the Journal of Experimental Biology, showed that at most angles, the snake model’s undulating shape generated enough lift to account for the animal’s gliding ability. (See more snake pictures.)

The researchers added that real flying snakes appear to glide even better than their findings from the 3-D printed model would suggest.

They are now investigating what else these reptiles might do to boost their aerial performances. As it is, these serpents remain somewhat Unexplained Flying Ophidians.

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