By: Cassidy Delamarter, University Communications and Marketing
After closely studying wandering salamanders for four years, a doctoral candidate at the University of South Florida (USF) discovered the amphibians have mastered “parachuting” down the world’s tallest trees. Christian Brown’s study, published in Current Biology, is the first to reveal aerial behaviors in the species.
Brown describes it as a newly discovered mode of locomotion for salamanders.
“A surprising and efficient way to get around. That’s what we’ve got here,” Brown said. “You’re expecting salamanders to crawl or swim, but you’re certainly not expecting them to parachute and be able to control their descent and move horizontally in the air and glide.”
While there are hundreds of species of salamanders across the globe, aerial behavior has never been observed until now in the 4-inch wandering salamander Aneides vagrans, which is native to California. The small but daring amphibians live in the redwood canopy in the tallest trees on Earth – nearly 400 feet off the ground. The descent from the canopy to the ground is a feat they’ve evolved to master.
The wandering salamanders whip their tail, right their body and maintain an upward posture to glide down the trees. Instead of spinning out of control, these creatures have managed to learn to parachute and precisely control their descent, using techniques similar to skydivers.
“If we hadn’t been looking at these animals this closely for this long, we never would have seen it,” Brown said.
This discovery comes after years of research. With the help of fellow biologists, Brown began reconstructing the movements of salamanders in 2018 inside the animal flight lab at the University of California, Berkeley. Together, the team studied the gliding postures of the salamanders inside a wind tunnel box. Over several trials, they witnessed the salamanders generate lift and slow their vertical speed up to 10% while falling – a discovery that Brown says was a total surprise and left him with new questions.
The salamanders have a basic four-legged body – with no webbing or skin-flaps traditionally seen in animals with aerial behaviors. Instead, they maneuver behaviorally.
“It goes to show that morphology alone doesn’t necessarily indicate functionality,” he said. He hopes this encourages researchers to take a second look at organisms they may have previously viewed as incapable of aerial behavior.
“It's an inspiring, iconic species that I think could get people thinking about the canopy world more and get us moving towards not just protecting the existence of redwoods, but trying to get us back to a point where canopy ecosystems thrive.”
Brown plans on continuing his research to monitor the salamanders and any environmental changes. Right now, the coastal redwoods are considered endangered and therefore the wandering salamander is inherently threatened. Brown says climate change is also expected to impact the fog patterns in the canopy, which could result in serious consequences for the salamanders, which rely on the fog’s moisture to breathe.
After graduation, Brown plans to pursue a post-doctoral fellowship to examine the relationships of genotypes, environment and phenotype – ultimately hoping to find out if falling is shaping the exceptionally long legs and large feet of the wandering salamanders, a physique different than that of most salamanders.
In the meantime, Brown is partnering with Alex Kirk of the USF Carney Lab to generate three dimensional images of the salamanders to examine the features that make them aerodynamic.