Turtles Not Among the "Silent Majority" of Reptiles

This is Scientific American 60-Second Science. I'm Christopher Intagliata. Got a minute?
Biologists used to think turtles belonged to the "silent majority" of reptiles, meaning if turtles made sounds, no one was listening.
One reptile guide from the 1950s went so far as to call them, quote, "deaf as a post."
But it turns out scientists just weren't listening hard enough.
Because in recent years, biologists have identified at least 11 different sounds in the turtle repertoire recorded both in and out of the water.
But what do they mean?
In the latest attempt to decode turtle talk, researchers tailed giant South American river turtles, Podocnemis expansa in Brazil, over a two-year span.
They recorded 220 hours of audio, capturing six of those 11 sounds.
Two of the calls were extremely common, occurring during just about every turtle activity.
Other calls the turtles made only during migration, or while nesting at night.
The findings appear in the journal Herpetologica.
The researchers still aren't sure what any of these sounds actually mean, or whether turtles can recognize each other by voice alone.
All the more reason, they say, to use these sounds in playback experiments , which might get these talking turtles out of their shells.
Thanks for the minute, for Scientific American 60-Second Science. I'm Christopher Intagliata.