The mystery of the whale song was solved by scientists

Scientists have figured out how some of the ocean's largest whales produce their haunting, complex songs.

Humpback whales and other baleen whales have developed a specialized “voice box” that enables them to sing underwater.

Whale song is limited to a narrow frequency that overlaps with the noise made by ships.

“Sound is extremely important for their survival, because it is the only way they can find each other to mate in the ocean,” explained Professor Koen Elemans, from the University of Southern Denmark, who led the study.

“[These are some] He told BBC News: “They are one of the most mysterious animals that have ever lived on this planet. They are among the largest animals, they are intelligent and very social.”

Baleen whales are a group of 14 species, including the blue whale, humpback whale, right whale, minke whale, and gray whale. Instead of teeth, animals have plates called baleen, with which they sift huge mouthfuls of small creatures from the water.

How they produce complex and often unnerving songs has remained a mystery until now. Professor Elemans said it was “very exciting” to discover this.

He and his colleagues conducted experiments using larynxes, or “voice boxes,” carefully removed from the carcasses of three stranded whales — a minke, a humpback whale, and a sei whale. They then blew air through the massive structures to produce sound.

In humans, our voices come from vibrations when air passes over structures called vocal folds in the throat. Instead, baleen whales have a large, U-shaped body with a pad of fat at the top of the throat.

This vocal anatomy allows animals to sing by recirculating air, and prevents water inhalation.

The researchers produced computer models of the sounds and showed that baleen whale song is limited to a narrow frequency that overlaps with noise from cargo ships.

“They cannot simply choose to sing louder, for example, to avoid the noise we make in the ocean,” Professor Ellimans explained.

His study showed how ocean noise can prevent whales from communicating over long distances. This knowledge could be vital for the conservation of humpback whales, blue whales and other endangered giants of the sea.

They also provide insight into questions researchers have been asking for decades about these eerie songs, which some sailors used to attribute to ghosts or mythical sea creatures.

Whale communication expert Dr Kate Stafford, from Oregon State University, described the study as “groundbreaking”.

She told the BBC: “The production and reception of sound is the most important sense for marine mammals, so any study that shows how sounds are produced has the potential to move the field forward.”

The research also paints an evolutionary picture of how whale ancestors returned from land to the oceans, and the adaptations that enabled underwater communication.

The way toothed whales produce sound is better understood, because these animals are easier to study. These marine mammals, which include dolphins, sperm whales and porpoises, blow air through a special structure in their nasal passages.

Dr Ellen Garland, from the Marine Mammal Research Unit at the University of St Andrews, said: “I have always wondered exactly how baleen whales – particularly humpback whales, which my research focuses on – produce the variety of sounds they do.”

“Studying large whales is extremely challenging at the best of times, but trying to uncover how they make sound when you may not even be able to see them underwater while vocalizing is an extra level of difficulty, so these researchers were very creative.”

Dr Stafford added that the mammals' ability to emit such complex vocal signals was “remarkable” and highlighted “how special these animals are”.