Sea animals were thought to be mute. A scientist just discovered they can talk

It is a known fact that acoustic communication plays a key role in parental care, mate attraction, and other behaviors. Nevertheless, not much has been studied about its evolutionary roots. There are also gaps in existing research due to a lack of information from groups that have not been widely studied.

A researcher from Switzerland decided to investigate if sea creatures, previously thought to be silent, can speak.

Gabriel Jorgewich-Cohen, a Ph.D. student at the University of Zurich, Switzerland, used microphones to record 53 species of marine animals, including turtles and lungfish, and found them showing "broad and complex acoustic repertoires."

Their study revealed solid evidence for 53 species of four major clades of land vertebrates – turtles, tuataras, caecilians, and lungfishes – in the form of vocal recordings and contextual behavioral information accompanying sound production. "This, along with a broad literature-based dataset including 1800 different species covering the entire spectrum, shows that vocal communication is not only widespread in land vertebrates but also evidence acoustic abilities in several groups previously considered non-vocal," first author Jorgewich-Cohen said in a statement.

The findings were published in Nature Communications.

The mute can speak

All this while, it was assumed that these marine creatures were mute. Jorgewich-Cohen told BBC News that not only are their sounds harder to detect but also that humans were biased towards creatures that live on land, thereby ignoring species underwater. "We know when a bird sings. You don't need anyone to tell you what it is. But some of these animals are very quiet or make a sound every two days," he told BBC News.

The voice recordings of the sea animals mostly comprised communication on mating and hatching.

"Sea turtles will sing from within their egg to synchronize hatching. If they call from inside, they all come out together and hopefully avoid being eaten," he told the publication. Meanwhile, turtles make mating noises, and tuataras make sounds to guard their territory.

The team used a technique called phylogenetic analysis to trace back the relationship between animals that make noise. The researchers combined data on the vocalization abilities of species like lizards, snakes, salamanders, amphibians, and Dipnoi with phylogenetic trait reconstruction methods. When they combined it with the data of well-known acoustic clades like mammals, birds, and frogs, the researchers could map vocal communication in the "vertebrate tree of life."

Acoustic communication in vertebrates can be traced to a single ancestor

They were then able to conclude that all acoustic communication in vertebrates descended from a single ancestor 407 million years ago when most species lived underwater.

"We were able to reconstruct acoustic communication as a shared trait among these animals, which is at least as old as their last common ancestor that lived approximately 407 million years before the present," explained Marcelo Sánchez, who led the study.

"Our results now show that acoustic communication did not evolve multiple times in diverse clades but has a common and ancient evolutionary origin," added Sánchez.

Study Abstract:

Acoustic communication, broadly distributed along the vertebrate phylogeny, plays a fundamental role in parental care, mate attraction and various other behaviours. Despite its importance, comparatively less is known about the evolutionary roots of acoustic communication. Phylogenetic comparative analyses can provide insights into the deep time evolutionary origin of acoustic communication, but they are often plagued by missing data from key species. Here we present evidence for 53 species of four major clades (turtles, tuatara, caecilian and lungfish) in the form of vocal recordings and contextual behavioural information accompanying sound production. This and a broad literature-based dataset evidence acoustic abilities in several groups previously considered non-vocal. Critically, phylogenetic analyses encompassing 1800 species of choanate vertebrates reconstructs acoustic communication as a homologous trait, and suggests that it is at least as old as the last common ancestor of all choanate vertebrates, that lived approx. 407 million years before present.