University of Zurich study finds vocal communication dates back more than '400 million years'

A study by researchers at the University of Zurich (UZH) found that vocal communication has been a means of communication for aquatic and land animals for more than 400 million years.

The study challenges previous ideas about vocal communication and notes that vocal communication is common among birds, mammals, reptiles, amphibians, and fish.

“Many of them are usually considered mute, but in fact show broad and complex acoustic repertoires,” according to the report.

The most common vocalization comes from vertebrates like birds who sing to communicate, as well as frogs croaking and dogs barking. This helps with aspects of their lives like parenting, attracting mates and various other behaviors, the report stated. The significance of vocal communication is widely recognized, but little has been known about its origins and how it evolved, or when it first appeared.

The international team of researchers focused on species that had not been studied much before. This involved 53 species from four major types of land vertebrates including turtles, tuataras, caecilians, and lungfishes. Vocal recordings and contextual behavior information associated with sound production was gathered, which led to finding evidence of vocal communication.

“Our study, including data from previously unexplored species, as well as an extensive literature-based dataset, comprising 1,800 different species across the spectrum, demonstrates that vocal communication is not only widespread in land vertebrates but also reveals acoustic abilities in several groups previously considered non-vocal," said Gabriel Jorgewich-Cohen, a doctoral student at the Paleontological Institute and Museum of UZH and the first author of the study.

According to the study, many turtle species that were thought to be mute, have diverse and intricate acoustic repertoires. The researchers used data on the vocalization abilities of species like lizards, snakes, salamanders, amphibians, and lungfish alongside phylogenetic trait reconstruction methods. Data from well-studied animals like birds, mammals and frogs was integrated and researchers were able to map vocal communication across the vertebrate tree of life.

“Through our analyses, we were able to reconstruct acoustic communication as a shared trait among these animals, showing that it is at least as old as their last common ancestor, which existed approximately 407 million years ago," said Marcelo Sánchez, who led the study.

The report noted that there is a convergent origin of acoustic communication from considerable variation in hearing apparatus and sensitivity, along with vocal tract morphology, for vertebrates. However, research in the study showed that hypothesis was limited due to a lack of data from species considered non-vocal or overlooked.

“Our results demonstrate that acoustic communication did not evolve multiple times in diverse clades but rather has a common and ancient evolutionary origin," Sánchez said.