The wandering salamander, Aneides vagrans, is about 4 inches long and lives all its life on the tops of redwood trees more than 150 feet above the ground. The researchers found that he has adapted to his high-altitude lifestyle by developing the ability to parachute and glide when he falls. Credit: Christian Brown
The “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 are based on postures very similar to those of humans parachuting to help slow down and control their fall.
High speed video of a tree salamander in a vertical wind tunnel. Credit: Christian Brown
“While hundreds of lungless salamander species are known to rise, airborne behavior had not been described,” said Christian Brown, a doctoral student at the University of South Florida and lead author of the study. “Our research on aerial behavior revealed that highly arboreal salamander species, especially the wandering salamander (Aneides vagrans), reliably engage in parachuting and planning to slow and direct their descent.”
After first reading about the wandering salamander in a National Geographic magazine in high school, Brown says he never stopped thinking about it. Years later, while working with wandering salamanders at Humboldt State University (now CalPoly Humboldt), he saw that amphibians would easily jump out of his hand or a redwood branch before quickly and steadily taking on positions of skydiving. I wanted to find out if and how this unexpected aerial behavior came into play in nature.
Wandering ducklings in a vertical wind tunnel at an air speed approximately corresponding to the terminal speed of the animal. Credit: Christian Brown
In the new study, he and colleagues such as Erik Sathe, Robert Dudley, and Stephen Deban describe the aerial performance of salamanders in which they maintain stable gliding positions by adjusting their legs and tail. In experiments with wind tunnels, salamanders constantly parachuted, slowing their vertical speed by up to 10% as they fell. They also combined the parachute with ripples in the tail and torso to slide at non-vertical angles about half the time.
“Observing salamanders, which are usually associated with ponds and streams, in the air is a bit unexpected in itself,” Brown said. “The most surprising thing for us was the exquisite level of control that the most arboreal salamanders had in the vertical wind tunnel. Wandering salamanders were especially skilled and seemed to instinctively display parachuting postures on first contact with the air current.
A. vagrans jumping. Credit: Christian Brown
“These salamanders were not only able to slow down, but also used fine-scale control in step, turn, and guidance to maintain upright body postures, perform inclined turns, and slide horizontally. air control was unexpected because these salamanders do not appear to have conspicuous characteristics for air control. “
Brown said what he finds most remarkable is that salamanders, and presumably other animals, do not necessarily need flashy control surfaces such as straps or leather flaps to parachute and slide. He wonders what other animals might have hidden their skydiving skills. Brown also hopes the findings will help draw attention to this unique species and its ancient canopy world.
The high-speed video reveals a big difference in how salamanders react to the fall. While terrestrial (non-tree) salamanders appear helpless during free fall in a vertical wind tunnel, tree salamanders maneuver with confidence. This suggests that tree dwellers have adapted to routine falls, and perhaps use the fall as a way to move quickly through the treetops of the tallest trees in the world. White spots are ingeniously connected paper disks
“Scientists have barely scratched the surface in the study of the sequoia canopy ecosystem and the unique wildlife it has shaped over evolutionary time,” he says. “With climate change at an unprecedented rate, it is vital that we collect more data on animals such as stray salamanders so that we can better understand, protect and preserve this delicate ecosystem.”
Meanwhile, he is 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 information on this research, see Salamander Parachutes with Parachutes and Sliding from Taller 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.DOI: 10.1016 / j.cub.2022.04.033