Your pet turtle may have something to share if you pay attention.
Nature Communications published a new study that identified 53 species of sounds. Many of these species were previously believed to be mute. The group included fifty species of turtles, including tuataras, a New Zealand-based reptile, and caecilians, a limbless amphibian.
Gabriel Jorgewich Cohen-Cohen, the lead researcher for the publication, is a doctoral student at the University of Zurich. He said that he was inspired to conduct the research after reading about a project in Brazil’s Amazon rainforest. A 2014 study revealed that Giant South American river tortoises found in the Amazon use vocal communication to communicate with each other, including calling their offspring.
Jorgewich-Cohen said that hearing the mother turtles call to their children made Jorgewich Cohen “super interested” and motivated him to identify more turtle sounds. “I was thinking maybe there were more turtles out here making sounds.”
He began to collaborate with a professor who had developed underwater sound equipment. He began recording turtles at home. He said, “At first I didn’t anticipate finding anything.”
He said that he found a lot more sounds than he expected.
This idea quickly grew into a larger research program. He explained that the idea was to concentrate on nonvocal animals. “I wanted deep to report these animals that aren’t known to voice, and try to understand the whole picture.”
Each species was recorded at least for 24 hours. Audio recordings include clicking, purring, hissing, and chirping.
After speaking with a specialist in New Zealand reptiles, he added tuataras to his list. She said that she had heard the animals make sounds while doing fieldwork. The distinctive crackly vocalizations of the Tuatara can be heard in the audio recordings.
He said that the sounds produced by caecilians were quite surprising. He said that he was surprised to find caecilians produce many sounds, in a very humorous way. Sometimes the caecilian recordings sound like purring and sometimes like loud burps.
He was also amazed by the wide range of species. Some turtles made many different sounds, while others had limited vocabulary. Others “wouldn’t stop talking,” repeating the same sounds often.
The research could have wider implications for biology. Jorgewich-Cohen stated that historically, the main hypothesis was that sounds made by mammals, birds, and frogs all had different evolutionary origins. This phenomenon is called convergent evolutionary, which occurs when species adapt in similar ways despite having different origins.
Jorgewich-Cohen’s extended evolutionary tree suggests that the ability to produce sounds is “derived from one source,” he stated. According to the paper, vocal communication is as old as the last common ancestral member of chocolate vertebrates, which are vertebrates that have lungs. It is approximately 407 million years old.
Jorgewich-Cohen’s team recorded 53 species. Jorgewich Cohen and his colleagues also used an acoustic communications dataset published by John Wiens, University of Arizona professor of evolutionary biology, and Zhuo Ch in Nature Communications 2020.
Jorgewich-Cohen did not consult Wiens for the study. Wiens stated that more research is necessary to determine the common origins of vocal communication.
Jorgewich-Cohen said that only turtles and other species make sounds. He did not say that these sounds are being used to communicate with one another. Jorgewich-Cohen’s team stated in the article that “the presence of a complex repertoire (presence of several sounds and/or harmony calls)” indicates “communicative meaning.”
Wiens stated that further research is needed to establish whether the sounds communicate meaning. Wiens referred to playback experiments. For example, researchers might play two male frog recordings to a female frog and see which one attracts her the most. Wiens claims that such experiments provide more evidence that sounds are used to communicate.
He said that the criteria used to determine if acoustic communication was being used by scientists weren’t clearly defined. Wiens stated that it is difficult to discern if they are making any sounds in some cases.
The article shows that animals are indeed more chatty than scientists believed.
Wiens stated that “they’ve documented more sounds making things than people had previously appreciated.” “That’s just the beginning.”
He said that playback experiments and other tests are needed to determine “if they have acoustic communications or not”.
Jorgewich Cohen says that he is determined to figure out what turtles want to communicate with each other.
“In most cases, we know that they make sounds. He said that we don’t know what they are saying.
“Besides that, I would love to know more about their cognition abilities – how they think and what the sounds mean.”
Furthermore, it is possible to contribute to conservation efforts by understanding the role that sound plays in turtles’ lives.
He said that turtles are the second-most endangered vertebrates after primates. “When we think of their conservation, we never consider noise pollution as a problem, and I believe now it is time to start thinking about how we can conserve them.”