Wandering salamanders parachute like human skydivers when jumping from great heights. The amphibians, which are native to redwood forests in California, US, were known to scale some of the tallest trees in the world. Now, for the first time, researchers have filmed the salamanders’ gliding behaviour.
“Although hundreds of species of lungless salamanders are known to climb, aerial behaviour had not been described,” says Christian Brown, a researcher at the University of South Florida, US, and lead author of a paper describing the gliding salamanders, which has been published in Current Biology.
“Our investigation of aerial behaviour revealed that highly arboreal species of salamanders, especially the wandering salamander (Aneides vagrans), reliably engage in parachuting and gliding to slow and direct their descent.”
It first occurred to Brown to investigate wandering salamanders’ parachuting behaviour when studying them at Humboldt State University, US. He noticed that the salamanders would often jump from his hands or tree branches, quickly forming skydiving postures.
This trick has been observed in species of tree-dwelling ant, spider, and lizard, just to name a few – in each case, either slowing the creature’s descent, or directing them back onto the tree trunk, when they jump or fall.
In this study, Brown and colleagues tested the skydiving pose by dropping salamanders into wind tunnels, with the airflows adjusted so that they’d be consistent with a fall from a treetop.
They performed this trial with four different species of salamander, some of which were known tree dwellers and some of which prefer lower habitats; as well as the wandering salamander they examined the arboreal salamander, the black salamander and the Ensatina salamander.
Five representatives from each species were used – 20 salamanders in total. The researchers did 45 wind tunnel trials on each species.
“To observe salamanders, which are generally associated with ponds and streams, in the air is a bit unexpected in and of itself,” says Brown.
“Most surprising to us was the exquisite level of control that the more arboreal salamanders had in the vertical wind tunnel. Wandering salamanders were especially adept and seemed to instinctively deploy skydiving postures upon first contact with the airstream.”
The arboreal salamanders consistently assumed skydiving postures, slowing their falling speed by 10%.
The arboreal salamander (A. lugubris), banking in mid-air. Credit: Christian Brown
“These salamanders were not only able to slow themselves down, but also used fine-scale control in pitch, roll, and yaw to maintain upright body postures, execute banking turns, and glide horizontally,” says Brown.
“This level of aerial control was unexpected because these salamanders do not seem to possess conspicuous features for aerial control.”
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The researchers are now delving into fluid dynamics to figure out exactly how the salamanders generate lift. If salamanders can do it, says Brown, it’s entirely possible that other animals in the redwood forests might be able to as well.
“Scientists have barely scratched the surface in studying the redwood canopy ecosystem and the unique fauna it has shaped through evolutionary time,” says Brown.
“With the climate changing at an unprecedented rate, it is vitally important that we collect more data on animals like wandering salamanders so we may better understand, protect, and preserve this delicate ecosystem.”
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