2025 - Young researcher discovers: turtles can talk

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Until recently, turtles were considered largely silent creatures. Then a young researcher from the University of Zurich listened to their conversations using special underwater microphones – and thereby re-wrote a chapter in evolutionary biology.

Gabriel Jorgewich Cohen had his key experience in the Amazon: Other researchers told him about turtles that supposedly made noises. Then he heard it himself: the delicate chirping of newly hatched turtles digging their way out of the nest.

Gabriel Jorgewich Cohen (33) comes from Brazil. For his turtle studies he will be awarded the Prix Schläfli 2024 from the Swiss Academy of Natural Sciencesfor the best dissertation in biology.

The biologist is currently working as a postdoctoral researcher at the Paleontological Institute at the University of Zurich. After proving that turtles communicate acoustically, he now wants to investigate the meaning of such sounds. His study object is the Arrus tortoise Podocnemis expansa – the largest freshwater turtle in South America. It was the babies of this sea turtle that Jorgewich Cohen first heard chirping in the Amazon – and that set his research in motion.

Photo: Basil Minder

The young biologist found this astonishing. Until now, turtles were considered silent creatures. The only exception is mating: the Seychelles giant tortoises, for example, which live on the islands of the same name in the Indian Ocean, accompany their lovemaking with impressive moans.

From an experiment in your own aquarium to a dissertation

Chirping baby turtles, males groaning during copulation. Jorgewich Cohen began to wonder: Were sounds perhaps more common in turtles than previously thought?

At first I wasn’t sure if it was my imagination. But over time it became clear that the animals actually vocalized.

At home in Sao Paulo he experimented on his own turtles. He tried to capture sounds in the aquarium using a borrowed underwater microphone. With success. “At first I wasn’t sure if I was imagining it. But over time it became clear that the animals actually vocalize.” Just like all the species that he later recorded.

This is what the chattering turtles sound like

In 2020, the biologist won a scholarship and became a doctoral student in Switzerland, at the Paleontological Institute at the University of Zurich. His plan is to do his doctorate on the evolution of turtles. One day he tells his supervisor about the audio recordings. He finds the project so exciting that he brings Jorgewich Cohen together with the bioacousticist Simon Townsend from the University of Zurich. “So bioacoustics became the main topic of my dissertation.”