It's a Bird, It's a Plane, It's a Snake!

Talk about bad press. No animals on the planet get as bad a rap as snakes. From the Biblical serpent to the trials and ordeals of Harry Potter, snakes are depicted as devils or monsters, so it's little wonder that many people break out in a cold sweat at just the thought of encountering one of these slithering reptiles.

So now comes biologist Jake Socha with news that may not bring comfort to the faint of heart. Some snakes can fly.

For eight years Socha has been studying snakes found in Southeast Asia that can leap from a branch high in a tree, and even make right-angle turns as they glide toward the ground or head for a tasty lizard in another tree.

He has chased them down in Singapore and Thailand, and he has been bitten more times than he can recall, so he knows firsthand that they aren't deadly. But the fact that they can fly, or more accurately glide, has captured his imagination.

His most recent research shows that the smaller of five species of flying snakes is the most proficient flier, and the snakes maintain aerodynamic control by flattening their entire bodies and undulating as they glide through the air.

Unlikely Fliers

Socha, who admits he was known as "Jake the Snake" in high school, became "Jake the Flying Snake" in grad school almost by accident. He didn't set out to study flying snakes, but soon after arriving at the University of Chicago to work on his doctorate in biology he was told to get with the program. Or in layman's terms, get some kind of grant to pay for his research.

"I didn't know what I wanted to work on," he says. But he remembered a professor who had told him about flying snakes, and how little was known about them, so he decided to "write up this grant on snakes and then move on to something more serious."

But the National Geographic Committee for Research and Exploration bought the idea, and Socha soon found himself heading for the jungles of Southeast Asia.

His work was hampered by the fact that there wasn't much information available, although scientists have known about flying snakes for more than a century. That's kind of amazing because, as Socha points out, snakes seem like very unlikely candidates for airborne maneuvers.

The body of a snake is basically a cylinder, which posed the first question.

"That is the least likely shape to be able to fly," says Socha, who is now a biologist with Argonne National Laboratory. So how do the snakes do it?

Socha's goal was to capture video images of the snakes, while in flight, and then use computers to help figure out the details. He got his first look at a flying snake while visiting a park in Singapore.

He was on an observation tower, primarily used by bird watchers, when he saw his first flying snake in the wild.

"This is a low forest, so we were up above the top of the trees, and there was a snake up there chasing geckos around," Socha says. But as he moved toward the snake it lost interest in the lizard "and he just took a dive off the tower and glided into the trees."

Undulation Is Key

Years later, and with tons of data, Socha has published reports in Nature and the Journal of Experimental Biology. Along the way he has picked up lots of bites from the five members of the Colubridae family of flying snakes, which are officially classified as harmless. For the record, the Chrysopelea ornata, or the golden tree snake, has the biggest teeth and the hardest bite and is the least friendly to humans. But the Chrysopelea paradisi, or the paradise tree snake, which has less of a bite and is considerably sleeker than the golden snake, turned out to be the star of the show.

The paradise tree snake is particularly graceful when it launches itself from the treetops. It hooks its tail over a branch, then forms the image of a "J" with its body as it launches itself up and outward. At first it descends rapidly, picking up the speed it needs for flight, and then it swoops outward, gliding farther than it drops, achieving true gliding flight.

The snake achieves that by flattening its body, something that is not uncommon among many species of snakes. Some do it to capture more rays from the sun, others do it to play dead.

As it glides it undulates, swinging its head from side to side and sending a wave down its body.

"It looks like it is swimming through the air," Socha says.

The snake manages to keep its body parallel to the ground and, apparently, undulation is key to its ability to control its flight. Unlike flying squirrels and other gliders, the snake doesn't just "spread its wings" and glide down to the ground.

"In essence you have a very complex dynamic motion," Socha says. That motion allows the snake to make turns, as much as 90 degrees during the early descent.

All of which brings us to the real question. Why has this family of snakes learned how to fly? What's the point?

Convenient Travel

"I don't have an answer to that," Socha says. Much more work needs to be done to figure out what's really going on here. But he has a few hunches.

The flying snakes like to dine on flying lizards, which also abound in Southeast Asia, so it's possible to picture some kind of aerial combat, with snakes zipping out of trees to nail flying lizards. But the snakes aren't all that proficient. They can't take off from the ground, and their flights are of fairly short duration.

So maybe there's another reason.

It's more likely, Socha speculates, that the snakes learned to fly so they could either escape from predators or move on quickly to a new foraging site, gliding from tree to tree in search of lizards.

"I think they use it for cheap travel," he says.

Let's hope these critters keep this to themselves. We don't really need flying rattlesnakes.
