Marco Werman: Here's a challenging question for you: what animal makes this sound? Yeah, if you're stumped, don't take it personally. For a long time, experts thought these creatures were completely mute, not to mention deaf as well. But researchers in Brazil have been committing that conventional wisdom to the thing of myth. The animals in question are turtles and the researchers are now recording the sound of turtles talking to each other. Here's another sample from a giant South American river turtle. Richard Vogt is one of the scientists on the project. He's a turtle expert at the National Institute for Amazon Research in Manaus, the capital city of the Brazilian state of Amazonas.
Richard Vogt: The turtles are vocalizing at the lower end of the human audible spectrum, at low frequencies, like whales. I don't mean the sounds are like the sounds that whales make but they're low frequency like whales and dolphins because low frequency sounds travel farther in water.
Werman: But here's the thing, Vogt says: turtles are not exactly chatty. Researchers would be listening sometimes for hours before they captured a single short phrase from one of them. And what do turtles talk about? Vogt says he's still gathering evidence but it's pretty clear that frequent topics are where to migrate, where to nest and when to flee from danger.
Vogt: Turtles were often thought to be kind of obtuse animals that just kind of clunked around in a shell and didn't have any social life. But we're showing that they're very social animals, they talk to each other, they decide where they're going. Published papers are finding hundreds of turtles hibernating under one bank. How do they all get there? It isn't by chance. They got there because they were talking to each other. The behavior of turtles is much more complex than people thought before.
Werman: Vogt says we've opened up a Pandora's Box. Now conservationists and researchers will have to consider the impact of noise pollution on certain species of turtles and even before they hatch, because it turns out some turtles are pretty vocal even when they're still inside the egg.