53 Species Aren't Mute After All

Turtles evolved millions of years ago and live in nearly every type of climate, according to Live Science, so it makes sense that they've have something to say. New research suggests they do, documenting noises made by 53 species—50 of them turtles—that had been thought to be mute. The others studied are tuataras, reptiles in New Zealand; caecilians, amphibians without limbs; and South American lungfish, CNN reports. Gabriel Jorgewich-Cohen, the lead researcher, started at home, recording his pet turtles with special sound equipment. His expectations weren't high, he said, but the recordings picked up Homer and other turtles making "a lot of sounds."

The project expanded. "I wanted to go deep on reporting these animals that are not known to vocalize, and try to understand this in the big picture," said Jorgewich-Cohen, a doctoral student at the University of Zurich. He recorded each species for at least 24 hours and heard clicking, chirping, hissing, and purring. He got a kick out of caecilians, which sometimes emit what sounds like a loud burp. The tuatara's sound is crackly. Some turtles made "made many different types of sounds," while others had a more limited repertoire but "wouldn't stop chatting." Jorgewich-Cohen's paper, published in Nature Communications, argues that the complex range, "a number of different sounds and/or harmonic calls)" shows that there's "communicative meaning" in the noises.

Others don't think we're there yet. John Wiens, an evolutionary biology professor at the University of Arizona whose previous work was tapped by the team, said more research would be needed to prove that. Jorgewich-Cohen said he does want to match sounds to the species' behavior, using video and audio recordings, per Phys.org. "Besides that, I would like to understand a bit about their cognition ability—how they think, more than actually what the sounds mean," Jorgewich-Cohen said. Wiens is wary of conclusions this early. Still, he said, Jorgewich-Cohen's team has "documented more things making sounds than people had appreciated previously. That's the first step." (More scientific study stories.)