- Georgina Rannard
- BBC News Climate and Science
A scientist has studied 53 aquatic creatures that he believes do not make sounds. And he found that they could, in fact, communicate.
Gabriel Jorgewich-Cohen points out that these creatures have always been sending their messages, but humans have never thought to hear them.
Use the microphones to record the species, including turtles, to communicate their desire to mate or hatch. And their findings rewrote some of what we know about evolution.
They suggest that all vertebrates that breathe through the nose and use sound to communicate descend from a common ancestor that lived 400 million years ago.
There is a strong debate in evolutionary biology about whether organisms descend from a single ancestor or from several different origins.
Jorgewich-Cohen is a doctoral student at the University of Zurich, Switzerland, and has begun work on the hypothesis that marine animals can communicate using sound. Use audio and video equipment to record 53 species in captivity around the world, including at Chester Zoo in England. Among them were 50 tortoises, a tuatara, a lungfish and a blind snake.
These animals were thought to be silent, but Jorgewich-Cohen notes that they are not heard because they are difficult to detect.
He told BBC News: “We know a bird’s song. I don’t need anyone to know what it is. But some of these animals are very silent or make noise every day.”
Jorgewich-Cohen also suggests that humans prefer terrestrial organisms and thus ignore aquatic species.
Videos of animals recorded when they made noises allowed the sounds to be associated with specific behaviours, distinguishing them from episodic sounds that do not convey messages.
“Sea turtles sing from inside the eggs to synchronize hatching,” he says. If they call from the inside [dos ovos]They all go out together and it’s easier to stop them from eating.”
The researcher claims that turtles also make sounds to indicate their desire to mate. He points to videos of turtle mating sounds popular on social media.
Jorgewich-Cohen also recorded noises made by tuataras – a type of New Zealand reptile – to protect their territory. He then set out to analyze what the discovery reveals about the evolution of animals that make sounds.
Fossils often do not “tell” scientists enough about animals that lived millions of years ago. Therefore, they compare the behavior of live animals.
Using a technique known as phylogenetic analysis, Jorgewich-Cohen traces the relationship between the animals that produce sounds.
This technique compares the behavior of species, assigning them as in a family tree. If humans and chimpanzees, for example, act by making sounds, this indicates that the common ancestor of both species was also producing sounds.
The researcher concluded that all vertebrate vocal communications descend from a common ancestor, 400 million years ago – in the Devonian period, when most species lived under water.
This conclusion contrasts with recent research that has traced communication by voice to several different species 200 million years ago.
Biologist Kathryn Hopiter, who was not part of the research, told BBC News that the recordings of these 53 species were well received and add to our knowledge of vocal communications.
“Comparing species like chimpanzees and humans only takes us a few million years back,” she explains. “We need to look at how common features between distant relatives expand our understanding hundreds of millions of years ago.”
The research has been published in the scientific journal Nature Communications.
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