Turtles are pretty quiet animals. Other than some shuffling through the sand or munching on vegetables, you don’t expect to hear much from your average chelonian.
But new research shows that many turtles — along with nearly every other vertebrate species that isn’t a fish (plus a few that are) — use vocal sounds to communicate. “We realized that this behavior is quite widespread,” says Gabriel Jorgewich Cohen, a Ph.D. student at the University of Zurich.
While in the Brazilian Amazon several years ago, he heard the unexpected vocal sounds of giant South American river turtles for the first time. Baby turtles make these sounds before they even hatch from their eggs, using it to synchronize their hatching and better their odds of surviving the most dangerous first moments of life. “They have less chance of being eaten and they share the work of digging up [as a result],” Jorgewich Cohen says.
When he returned home to Europe, Jorgewich Cohen connected with a professor from another university to borrow a hydrophone — a device that can detect and record underwater sound — and used it on his pet sliders and tortoises. With some patience, he heard the animals vocalizing, albeit not very often.