Parachuting Salamanders Jump in parachutes and slide from the tallest trees [High Speed Video]

High-speed video of an arboreal salamander in a vertical wind tunnel.

Salamanders that live their entire lives in the canopy of the world’s tallest trees, California’s coast redwoods, have developed behavior well-adapted to the dangers of falling from great heights: the ability to parachute, glide, and maneuver in the air.

Flying squirrels, as well as numerous species of gliding frogs, geckos, ants, and other insects, are known to use similar aerobatics when jumping from tree to tree or falling, to stay in trees and avoid landing on the ground. .

Similarly, researchers believe this salamander’s skydiving abilities are a way of returning to a tree it fell or jumped from, to better evade ground-based predators.

“While parachuting, they have an exquisite amount of maneuverable control,” said Christian Brown, a doctoral candidate at the University of South Florida (USF) in Tampa and first author of a paper on these behaviors. “They are able to turn. They are able to flip if they are turned upside down. They are able to hold that skydiving posture and move their tails up and down to do horizontal maneuvers. The level of control is simply impressive.”

The aerial prowess of the so-called wandering salamander (Aneides vagrans) was revealed by high-speed video images captured in a wind tunnel in the[{” attribute=””>University of California, Berkeley, where the salamanders were nudged off a perch into an upward moving column of air, which simulates free fall.

A vagrans Salamander

The wandering salamander, Aneides vagrans, is about 4 inches (10 centimeters) long and lives its entire life in the crowns of redwood trees more than 150 feet above the ground. Researchers discovered that it has adapted to its high-rise lifestyle by developing the ability to parachute and glide when falling. Credit: Christian Brown

“What struck me when I first saw the videos is that they (the salamanders) are so smooth — there’s no discontinuity or noise in their motions, they’re just totally surfing in the air,” said Robert Dudley, UC Berkeley professor of integrative biology and an expert on animal flight. “That, to me, implies that this behavior is something deeply embedded in their motor response, that it (falling) must happen at reasonably high frequencies so as to effect selection on this behavior. And it’s not just passive parachuting, they’re not just skydiving downwards. They’re also clearly doing the lateral motion, as well, which is what we would call gliding.”

The behavior is all the more surprising because the salamanders, aside from having slightly larger foot pads, look no different from other salamanders that aren’t aerially maneuverable. They have no skin flaps, for example, that would tip you off to their parachuting ability.

The high-speed video reveals a big difference in how the salamanders react to falling. While ground-dwelling (non-arboreal) salamanders appear helpless during free fall in a vertical wind tunnel, arboreal salamanders maneuver confidently. This suggests that tree dwellers have adapted to routine falls, and perhaps use falls as a way to move quickly in the tops of the world’s tallest trees. The white dots are paper discs glued with water to track the movement of the head, body, and tail. Credit: Video produced by Roxanne Makasdjian with images courtesy of Christian Brown

“Wandering salamanders have big feet, long legs and active tails. All of these things lend themselves to aerial behaviors. But everyone assumed it was for scaling, because that’s what they use those features for when we look at them,” Brown said. “So it’s not really a dedicated aerodynamic control surface, but it works as both. It helps them climb, and it seems to help them parachute and glide as well.”

Among the questions the researchers hope to answer in future research are how salamanders manage to parachute and maneuver without obvious anatomical adaptations for gliding and whether many other animals with similar aerial abilities have never been noted before.

“Salamanders are slow, you don’t think they have particularly fast reflexes. It’s life in the slow lane. And flight control is about responding quickly to dynamic visual cues and being able to point, orient and change your body position,” Dudley said. “So, it’s a bit strange. How often can this be happening, anyway, and how would we know?

An article describing the behavior was published on May 23, 2022 in the journal current biology.

life in the canopy

Using the wind tunnel, Brown and UC Berkeley graduate student Erik Sathe compared the gliding and skydiving behavior of a. vagabonds Adults measure about 4 inches (10 centimeters) from snout to tip of tail, with the abilities of three other species of salamanders native to Northern California, each with varying degrees of arboriculture, that is, the propensity to climb or live in trees. The wandering salamander, which probably spends its entire life in a single tree, bobbing up and down but never touching the ground, was the most proficient parachutist. A related species, the so-called tree salamander, A. lugubriswhich lives in lower trees, such as oaks, was almost as effective at parachuting and gliding.

Two of the less arboreal salamanders: Ensatina eschscholtziia salamander that lives on the forest floor, and A. flavipunctatus, the occasional tree-climbing black spotted salamander, essentially flapped ineffectively during the few seconds they were airborne in the wind tunnel. All four species are plethodontid, or lungless, salamanders, the largest family of salamanders and are found primarily in the Western Hemisphere.

Aneides vagrans parachuting in a vertical wind tunnel at a speed roughly corresponding to the terminal velocity of the animal. Credit: Christian Brown

“The two less arboreal species are very agitated. We call it inefficient undulating motion because they don’t slide, they don’t move horizontally, they just float around in the wind tunnel freaking out,” Brown said. “The two most arboreal species never really stirred.”

Brown encountered these salamanders while working in Humboldt and Northern California counties with nonprofit and university conservation groups that mark and track the animals that live in the redwood canopy, primarily in mature forest below about 150 feet. ground. Using ropes and lifts, biologists regularly climb redwoods, the tallest of which rise to a height of 380 feet, to capture and mark wandering salamanders. Over the past 20 years, as part of a project led by James Campbell-Spickler, now director of the Sequoia Park Zoo in Eureka, researchers found that most of their tagged salamanders could be found in the same tree year after year, even though at different heights. They live mainly on fern mats that grow on decaying plant matter that accumulates at the junctions of large branches. Brown said few marked redwood canopy wandering salamanders have been found on the ground, and most of them were found dead.

Brown noticed, as he picked them up to mark them, that the salamanders quickly slipped out of his hands. Even a light tap on a branch or a passing shadow was enough to make them jump out of the redwood canopy. Given his location high above the forest floor, his nonchalant leaps into the air were surprising.

A. vagrans jumping

A. vagrans jumping. Credit: Christian Brown

“They jump, and before they’re done moving, they have their forelimbs extended and they’re ready to go,” he said. “So jumping and parachuting are very close. They take over immediately.”

When approached by Dudley, who has studied such behavior in other animals, he invited Brown to bring some of the salamanders into his wind tunnel to record their behavior. Using a high-speed video camera shooting at 400 frames per second, Brown and Sathe filmed the salamanders as they floated in the air column, sometimes for up to 10 seconds.

They then analyzed the frames to determine the animals’ airborne posture and deduce how they used their legs, bodies and tails to maneuver. They usually fell at a steep angle, just 5 degrees from vertical, but based on distances between branches in the crowns of redwoods, this would usually be enough for them to reach a branch or trunk before hitting the ground. Skydiving reduced his free fall speed by about 10%.

Brown suspects his aerial skills evolved to deal with falls, but they have become part of his behavioral repertoire and perhaps his default method of descent. He and USF student Jessalyn Aretz found, for example, that walking downhill was much more difficult for the salamander than walking on a horizontal branch or climbing a log.

“That suggests that when they do wander, they are likely to walk on flat surfaces or walk uphill. And when they run out of habitat, as the upper canopy gets drier and drier, and there’s nothing else for them up there, they might go back to those better habitats,” he said. “Why walk down? You’re probably already exhausted. You have burned all your energy, you are a small salamander of 5 grams and you have just climbed the tallest tree on Earth. You’re not going to turn around and walk down, you’re going to take the gravity lift.”

brown sees a. vagabonds as another symbol of old growth forests that is similar to the spotted owl in that it is found primarily in the canopy of older, taller redwoods, but also in Douglas fir and Sitka spruce.

“This salamander is a representative example of the part of the redwoods that was almost completely lost to logging: the canopy world. It’s not there in these new forests created by the logging companies,” he said. “Maybe it would help not only efforts to conserve redwoods, but also to restore redwoods, so we can get canopy ecosystems. Restoring redwoods to the point of fern mats, to the point of salamanders in the canopy, that would be a new barrier to conservation.”

In the meantime, this ancient forest dweller has much to tell us about the evolution and perhaps origin of flight, Dudley said.

“It’s (gliding) a novelty, something unexpected in a well-studied group of animals, but it illustrates the urgency with which tree-dwelling animals must develop aerial ability, even if they don’t have wings,” Dudley said. “Flight, in the sense of controlled aerial behavior, is very common. They are controlling their body posture and moving laterally. This predisposes many, many things that live in trees to develop flapping flight, which is probably difficult to evolve and why it has only appeared three times on the planet today.”

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

Co-authors on the paper with Brown and Dudley are Sathe and Stephen Deban, a professor of integrative biology at the University of South Florida.

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