Whales sing loud enough for their songs to travel across the ocean, but knowledge of the mechanism behind this ability has remained a mystery.

Scientists now believe they have a first finding, and it’s something not seen in other animals: a specialized ‘voice box’.

Experts say the discovery, though based on a study that is too small to be conclusive, will direct future research into how whales communicate.

In a paper published Wednesday in the journal Nature, Coen Elemans of the University of Southern Denmark and his colleagues studied the voice boxes, or larynxes, from three dead women.

In the lab, scientists blew air through the voice boxes under controlled conditions to see which tissues could vibrate. The researchers also created computer models of the Sei whale’s vocalizations and matched them to recordings of similar whale sounds taken in the wild.

The ancestors of whales were land dwellers about 50 million years ago before moving to the water. Elemans said animals have adapted their voice boxes over tens of millions of years to make sounds underwater.

Unlike humans and other mammals, whales do not have teeth or vocal cords. Instead, in their voice boxes, they have a U-shaped tissue that allows them to breathe huge amounts of air and a large “cushion” of fat and muscle not seen in other animal species. Whales sing by pressing the tissue against the blubber and muscle pad, Elemans said.

“This is the most comprehensive and important study to date of how whales produce loud sounds, which has remained a mystery to the research field for many years,” said Jeremy Goldbogen, an associate professor of oceanography at Stanford University, who was not involved in the new study. research.

He noted that more needs to be studied “given the extremely diverse acoustic repertoires” of whales. Humpback whales, for example, are known to compose elaborate songs that travel across oceans and pods of whales.

As loud as whale songs are, modeling suggests that humpbacks and related species cannot produce sounds louder than the shipping industry, Elemans said.

“They are really affected by the shipping noise and it greatly reduces their ability to communicate,” he said. “There’s just no way they can produce louder sounds.”

Because some whales sing as a mating call, the disruption of these songs by the shipping industry is potentially worrisome, said Michael Noad, director of the Center for Marine Science at the University of Queensland in Australia. It was not part of the study of Nature.

“For whale populations that are really dispersed, like Antarctic blue whales, they may not be able to find mates in a noisy ocean environment,” he said, noting that whale species like humpbacks that congregate in large numbers are more likely to be unaffected. from noise pollution.

The whale voice boxes tested were from juveniles, not adult males, singing. Because of this, said whale expert Joy Reidenberg, further experiments on adult males are needed to confirm the study’s findings.

But Reidenberg, who works for the Center for Anatomy and Functional Morphology at the Icahn School of Medicine at Mount Sinai in New York, noted that laboratory research is probably closer than ever to uncovering the mechanism behind whale song.