Study finds salamanders ‘parachuting’ in California redwoods

photo of forest
Christian Brown/Courtesy
A study published Monday by researchers from the University of South Florida and UC Berkeley found that salamanders appear to be “parachuting” as they change speed and glide in the canopies of tall trees.

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Salamanders living high up in California’s redwoods have aerial behavior that allows them to control their posture in the air, a study conducted by the University of South Florida and UC Berkeley researchers found.

Published in Current Biology on Monday, the study revealed that salamanders living in the canopies of tall trees such as redwoods and the Douglas fir in Northern California can maneuver both their speed and direction. By changing the speed of their descent, salamanders can “glide” or move laterally, according to the study.

“They can glide off to the side and target landing spots and land back on the tree they started out, making a 180 in the air,” said UC Berkeley professor of integrative biology Robert Dudley, a co-author of the study.

To observe how these salamanders move in the air, the researchers placed them in a vertical wind tunnel, which is a fan pointed upwards, according to campus doctoral candidate Erik Sathe.

Dudley explained that by making the column of air move at seven meters per second, they could mimic how the salamanders would fall at near-terminal velocity.

“Aerodynamic forces like lift and drag depend on the relative speeds of the air and an object,” Sathe said in an email. “Instead of having the salamander fall through the air, we moved air past a salamander, which produces the same forces.”

The team then closely monitored the salamanders’ movements using a high-speed camera and motion-capture technology to “reconstruct” their behaviors, Sathe added.

According to Dudley, using cameras that capture 400 to 500 frames per second allowed the researchers to observe how the salamanders’ velocity, center of mass and posture changed.

“With two separate cameras and calibration frames, so with markers on bodies and limbs of salamanders, you can reconstruct 3D points to get a kinematic description of how the animal is moving,” Dudley said.

Dudley also noted how this research led by doctoral candidate Christian Brown at the University of South Florida was motivated by previous work in “aerial things that don’t have wings,” such as gliding spiders.

For Sathe, these “parachuting” salamanders show that things people wouldn’t expect to have aerial control actually can.

“There are probably a lot of things that can control body orientation and aerodynamic forces while in the air that we haven’t documented yet,” Sathe said in an email. “This is especially exciting when thinking about how and why animals become airborne in the first place and how things like gliding and flight evolved.”

Dudley believes this demonstrates how little we know about canopy biology, despite the existence of entire ecosystems up above.

In the future, the researchers want to know more about the evolution of flight and the salamanders’ body movements in the air.

“We also want to see what the salamanders are actually doing in the wild,” Sathe said in an email. “We want to know how they start to fall from the redwood canopies, and what implications controlled descent has for their ecology.”

Aileen Wu is a research and ideas reporter. Contact her at [email protected], and follow them on Twitter at @aileenwu_.