Baleen whales have long been thought to sing to each other in a way that scientists have never been able to pinpoint, but new research has revealed how the world's largest mammals communicate.
These species, which include humpback whales and blue whales, use low-frequency sounds of up to 300 Hz to speak underwater, which are absorbed less quickly in the ocean.
Scientists have now discovered that mammals have unique laryngeal structures that allow them to speak, orient themselves, and find partners.
In their study, researchers from the University of Southern Denmark analyzed the voice boxes of sei whales and humpback whales, and were able to simulate how air flows inside this organ to produce sounds.
They found that whales have a large, U-shaped skeleton made up of long, cylinder-shaped tissue called the arytenoid that fuses at the base.
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The structure, found only in baleen whales, allows them to use air to generate low-frequency sounds in the ocean and helps them perform shallow, “explosive” breathing.
“We found that this U-shaped structure compresses a large fat pad inside the larynx,” said Koen Elemans, a professor in the Department of Biology at the University of Southern Denmark.
“When the whales push air from their lungs beyond this pad, they start to vibrate and this generates very low-frequency sounds underwater.
“Our experiments have shown for the first time how whales produce their very low-frequency sounds.”
But the team said the whales' songs conflict with the sounds humans make in the ocean, which typically range between 30-300 Hz.
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The researchers wrote in the journal Nature that baleen whales can only communicate at a maximum depth of 100 meters below the surface, where they are likely to drown due to noise from marine traffic, and called for better regulation to protect the species.
Professor Ellimans added: “Compared to the 1970s, our oceans are now more filled with human-caused noise from shipping lanes, drilling activities and seismic thrusters.
“We need strict regulations for such noises, because these whales rely on sound to communicate.
“Now we show that despite their amazing physiology, they cannot escape the noise that humans make in the oceans.”
Baleen whales are among the largest whales the animals On this planet, it can reach a length of 100 feet and weigh up to 200 tons.
They are named after the baleen plates made of keratin – also found in fingernails and hair – in their mouths, which they use to sift plankton and other small organisms from the water.
