This is Scientific American, 62nd Science, I'm Pakinem Imer.

Clicks, clocks, grunts, and snorts.

These are not sounds that we typically associate with turtles.

They're actually thought to be very quiet or even silent.

But it looks like we may have grossly underestimated how much sound they can make.

Now a new study in Nature Communications has collected vocal recordings from 53 species

of turtles and other animals that were otherwise considered to be mute.

Those clicks you've just heard were calls made by baby giant Amazon River turtles, swimming

together and vocalizing.

A group of evolutionary biologists and other scientists in five different countries

poured over these recordings and combined them with vocal repertoire of about 1800 animal

species from other studies.

They were able to piece together evidence that the last common ancestor of all lung fish

and tetrapods started vocalizing more than 400 million years ago.

In just in case you're not familiar, tetrapods are four limped vertebrates that include amphibians,

mammals, birds, and reptiles.

This at least 100 million years earlier than previous studies had suggested.

The new revelations amount rewriting of the acoustic history of animals with bagboats.

I did field work in the Brazilian Amazon with a researcher that published one of these

first papers showing that turtles can communicate acoustically and that inspired me.

So I went back home and I got piece of equipment and I started recording my own pets and I discovered

that they were producing sounds as well and the species I had were not known to produce sounds.

...