A new study is shedding light on the incredible world of California’s temperate forests and the daring survival techniques of one of its inhabitants: parachuting salamanders.
The study, published Monday in the journal Current Biology, shows how salamanders living in the canopy are able to parachute consistently, slowing down and controlling their movements.
Salamanders are not exactly known for their agility and dexterity: people associate them with rotten logs and streams, said Christian Brown, a doctoral student in biology at the University of South Florida. But the study shows the counterintuitive nature of these creatures and has implications for other organisms that may not look great but have special abilities.
“This is a five-gram salamander that climbs the tallest trees in the world and is not afraid to make a leap of faith,” Brown said.
Scientists knew before that wandering salamanders lived in redwoods and in dense numbers, sometimes 30 or 40 individuals at the top of a tree.
Amphibians are lungless: they breathe through their skin and the tissue around their mouths. The wet forest fern mats on the canopy helped keep them from drying out and provided a safe haven.
By 2020, Brown and his colleagues had published a detailed description of how salamanders jump. Unlike other species, they used two feet instead of one. They don’t come out so quickly horizontally, hinting at something: jumping with less power could contribute to stability after the jump, Brown said. “It’s better to have control after the jump than to jump too hard.”
After all, if you want to jump from the tallest trees in the world, you’ll have to parachute and glide.
To test his skydiving skills, Brown put the five-inch-long salamanders in small wind tunnels, the same kind you might see in an indoor skydiving park, just the size of a salamander. And like human paratroopers, salamanders moved their bodies and limbs to slow their descent, successfully slowing their speed by 10%, the researchers found.
“This is a five gram salamander that climbs the tallest trees in the world and is not afraid to make a leap of faith.” Photography: John P Clare
Three other species of salamanders fell into the wind tunnels. Wandering salamanders, Brown says, “slowed down the best.” They also pumped the tail and moved the limbs to change direction horizontally.
Why did the species develop this special trick, as salamanders do not appear to be very aerodynamic or prone to flying? Because salamanders cannot answer this question themselves, scientists must use what we know about the ecosystem and come up with hypotheses to test, Brown said.
One idea is that they use to jump and fall to quickly escape predation. In the lab, just tickling the tail of a stray salamander will make it jump.
Another idea is that the movements of salamanders are a form of locomotion: an elevator up and down the canopy of the forest. Brown believes most jumps take place from tree to tree at 40 to 80 feet above the ground, far enough away where a fall might not be fatal, but would endanger a salamander during a long walk home. Another study showed that salamanders would take hours or days to return to the crown from the ground. Giant Pacific salamanders chase the forest floor and feed on vagrants, while all their resources (food, moisture, mate) would be high up in the maze of mats and ferns. So jumping would be an easy way to get around. “It’s more efficient and minimizes the risks,” Brown said. “Ultimately, we think jumping is a prevention for falling to the forest floor.”
Researchers now want to assess in more detail how salamanders navigate the air in their natural environment, at the top of trees. They are using ladders to drop them a few feet outdoors combined with on-site observations from up to 200 feet high to test this behavior in the field. They are also taking the sliding patterns observed in the lab and overlaying them with maps of redwood crowns and salamander locations to better visualize the effectiveness of sliding at sharp angles in their habitat.
The study has shown that salamanders can move their bodies in completely unexpected ways: turning, parachuting, gliding to the next branch. “The level of control is a little exceptional, so it’s exciting,” he said. “This is an animal that can jump deftly to navigate its habitat … and you may be surprised.”