Skydive from parachute salamanders and glide from the tallest trees in the world
“Wandering salamanders” live in some of the tallest trees in the world. They are also known to jump when disturbed. Now scientists report in the journal Current biology on May 23, 2022, that these salamanders rely on postures similar to those of humans parachuting to slow and control their fall.
“Although hundreds of species of lungless salamanders are known to climb, aerial behavior has not been described,” said Christian Brown, a doctoral student at the University of South Florida and the study’s lead author. “Our aerial behavior survey revealed that highly arboreal salamander species, particularly the wandering salamander (Vagrans aneids), reliably engage in skydiving and gliding to slow and direct their descent.
After a first reading on the wandering salamander in a National geographic magazine in high school, Brown says he never stopped thinking about them. Years later, while working with wandering salamanders at Humboldt State University (now CalPoly Humboldt), he saw that the amphibians easily jumped from his hand or from a redwood branch before quickly and systematically adopt skydiving postures. He wanted to know if and how this unexpected aerial behavior played out in nature.
Vagrans aneides parachuting into a vertical wind tunnel at a speed corresponding approximately to the terminal velocity of the animal. 1 credit
In the new study, he and his colleagues, including Erik Sathe, Robert Dudley and Stephen Deban, describe the aerial performance of salamanders in which they maintain stable gliding postures by adjusting their legs and tail. In wind tunnel experiments, salamanders constantly parachuted, slowing their vertical speed by up to 10% as they fell. They also coupled skydiving with undulations of their tail and torso to perform glide at non-vertical angles about half the time.
“Seeing salamanders, which are usually associated with ponds and streams, in the air is a bit unexpected on its own,” Brown said. “Most surprising to us was the exquisite level of control the more arboreal salamanders had in the vertical wind tunnel. The wandering salamanders were particularly adept and seemed to instinctively deploy parachuting postures upon first contact with the airstream.
“These salamanders were not only able to slow themselves down, but they also used precise pitch, roll, and yaw control to maintain an upright body posture, execute banked turns, and glide horizontally. This level of air traffic control was unexpected as these salamanders do not appear to possess any outstanding air traffic control characteristics.
Brown said what he finds most remarkable is that salamanders, and presumably other animals, don’t necessarily need flashy control surfaces such as webbing or skin flaps to parachute and hover. He wonders what other animals might have hidden skydiving abilities. Brown also hopes the findings will help bring attention to this unique species and its ancient canopy world.
The high-speed video reveals a big difference in how the salamanders react to the fall. While terrestrial (non-arboreal) salamanders seem helpless during a free fall in a vertical wind tunnel, arboreal salamanders maneuver with confidence. This suggests that tree dwellers have adapted to routine falls and may use falling as a way to move quickly through the canopy of the world’s tallest trees. The white spots are paper discs attached with
“Scientists have barely scratched the surface studying the ecosystem of the redwood canopy and the unique fauna it has shaped through evolution,” he says. “With the climate changing at an unprecedented rate, it is vitally important that we collect more data on animals like wandering salamanders so that we can better understand, protect and preserve this delicate ecosystem.”
In the meantime, he’s using computational fluid dynamics and 3D reconstruction software to determine how salamanders generate lift. He says future research should include salamanders with more diverse morphologies and examine the sensory cues that lead to their aerial behaviors.
For more on this research, see Skydiving Salamanders Parachute and Glide From the Tallest Trees.
Reference: “Gliding and parachuting by arboreal salamanders” by Christian E. Brown, Erik A. Sathe, Robert Dudley and Stephen M. Deban, May 23, 2022, Current biology.