Cartwheeling seems like it should require both arms and legs. But some itty-bitty snakes in Southeast Asia manage it without either.
Scientists first shared snapshots of a dwarf reed snake (Pseudorabdion longiceps) cartwheeling away from danger in 2023. Now, videos of three Pseudorabdion species hightailing it down a racetrack in the lab have offered a closer look at this rare and strangely acrobatic behavior.
Each snake starts with its body curled into a C shape, head lifted off the ground and facing the way it’s going. It then whips its tail out behind it, briefly becoming airborne. The snake flips its tail forward and down past its head. When the snake’s tail hits the ground in front of it, another roll begins, researchers report October 19 in Current Biology.
“What a cool snake behavior,” says Jessica Tingle, a biologist at Brown University in Providence, R.I., not involved in the work. “I find it especially amazing that an elongate animal like a snake can manage to roll, especially given that they do it in such an explosive way, which probably asks a lot of their muscles and bones.”
Yosuke Kojima was equally surprised when a colleague in Sarawak, Malaysia recounted witnessing this “very weird” behavior in 2019. So the researchers collected snakes from Malaysia’s Kubah National Park. They scooped up 11 P. saravacense, one P. collaris, one P. longiceps, plus six Calamaria reed snakes for comparison.
Finding the snakes was no easy task. They were only about 11 to 28 centimeters long. “They always hide under the leaves,” says Kojima, an ecologist at Toho University in Chiba, Japan. But were any of the snakes able to cartwheel away from the researchers? “No,” Kojima laughs. “We are quicker than them.”
The team set up a 2.2-meter-long racetrack and placed the snakes one at a time at one end. A gentle tap coaxed the snakes to move and cameras above and beside the track recorded the action. None of the Calamaria snakes cartwheeled, but all of the Pseudorabdion snakes did. At full tilt, they tumbled at 1.7 to 3.7 meters per second — about six to 13 kilometers per hour.
Through it all, the snakes held their heads fairly steady — reminiscent of how flying snakes hold their heads stable while launching into the air, the researchers say.
“I am very curious how such a strange and possibly demanding movement evolved … whether dwarf reed snakes have something special in their anatomy, physiology or neural control that lets them do it when their close relatives apparently can’t or don’t,” Tingle says. “Are their brains different in some way to let them coordinate a fast and unusual movement? Or do all snakes have the basic equipment, and they just don’t use it?”
Those may be open mysteries. But catching snakes cartwheeling on camera does tie up one loose end for Tingle.
“Some writers in the 1800s talked about ‘hoop snakes’ and described their motion as rolling, but that seemed pretty fantastical to me, and I chalked it up to overly inventive imaginations,” Tingle says. Those 19th century authors may or may not have been describing the exact behavior Kojima’s team recorded. “Either way, it’s neat to find out a real animal does something reminiscent of a fantastical old story.”
