Defector (not just a sports blog) reports on a zoological discovery – that turtles have been vocalizing all along, but we’ve only realized they had voices in the last couple of years. And not just as a sex thing:
In October, a group of researchers that included Ferrara published a paper in Nature Communications finding that at least 50 species of turtles, as well as a few other cold-blooded species long dismissed as mute, do actually vocalize. The researchers recorded all of these species emitting a range of snuffles, grunts, snorts, and farts—in the acoustic sense. Not only do these results overturn the assumption that turtles are always silent, they also suggest that vocalizations can be traced back to a common ancestor about 407 million years ago.
In other words, to complete her PhD, Ferrara (and a microphone) had to venture into the Amazon, find the giant South American river turtles, and then listen to see if they were making sounds. The first year, she listened only to adults. The next, she listened to hatchlings. She eventually recorded the eggs too, and learned the turtles start to vocalize in an embryonic form. “We were so excited with what we had discovered. And then we started to ask ourselves, ‘How about the other species?’”
Gabriel Jorgewich-Cohen, an evolutionary biologist at the University of Zurich and the lead author on the new paper, first learned about turtle talk through Ferrara’s paper on the vocalizations of the giant South American river turtle. Intrigued, he went to the Amazon to do fieldwork with some of the authors of Ferrara’s paper and heard the turtles vocalize for the first time. The experience reminded him of another time he’d heard tortoises vocalizing…
Although Jorgewich-Cohen had a pair of tortoises at home as well as a black-bellied slider turtle, he had not been lucky enough to hear their mounting-related melodies. But he remembered the day he brought his second tortoise home to meet the first tortoise, the two began moving their heads around and making “funny sounds that somehow sounded like chickens,” he said. He started recording his black-bellied slider, too, putting a recording device in its tank for hours and then analyzing the resulting sounds—of which there were many.
Jorgewich-Cohen began an international tour of turtles, traveling to various institutions that had rare species in tanks. Some visits were as easy as dropping a microphone into a turtle tank and waiting for a few hours. Others proved more difficult, depending on the turtle. He visited Turtle Island in Graz, Austria, which houses two-thirds of all living species of turtles. “It’s insane,” he said. “I think it’s the biggest collection of living turtles in the world.” Turtle Island cares for several softshell turtles from New Guinea, a species called Pelochelys bibroni that can grow over a meter long. “They’re fine, normally, but if you try to pick them up, they can become very aggressive,” Jorgewich-Cohen said. “You don’t want to get bitten by one, it feels like it could take your arm off.” Instead, the keepers opted to remove every single other species of animal from the tank to isolate the hard-hearted softshells.
But the recording of the softshells was reward enough.
You can listen to some recordings at the link, and read Jorgewich-Cohen’s and Ferrara’s research here, in Nature Communications.