Mysticetes or “right whales” (suborder Mysticeti) sing thanks to a unique system in the larynx, which works on a principle similar to that of land mammals such as humans and described for the first time in a study.
Humpback whale. PHOTO Shutterstock
In the sea about fifty million years ago, the ancestors of whales had to adapt their communication system to avoid drowning. Odontocetes, – cetaceans with teeth like the current dolphin – developed a nasal organ that allows them to emit sounds, writes Agerpres.
The researchers assumed that, in turn, mysticetes used their larynxes to produce vocalizations. But the mechanism of their anatomy that enables these songs was not really understood, notes an article in the journal Nature that accompanies the study.
The first sailors had detected these strange sounds, initially attributed to mythical creatures or “ithe imagination of drunken sailors”remembers the American anatomist Joy Reidenberg in the article.
Only after the Second World War, from the sounds recorded by military hydrophones, did researchers understand that these songs were produced by whales.
In the study published by Nature, an international team led by Coen Elemans, from the biology department of the University of Southern Denmark in Denmark, combined experiments on the larynxes of three species of mysticetes (humpback whale, minke whale, sei whale) with anatomical models and informatics.
He concluded that these animals developed “unique laryngeal structures for sound production”.
Once the lungs are full of air, after inhaling and closing the valves that prevent water from entering, the whale produces the song by pushing the air through the larynx.
The measurements made by Coen Elemans' team also establish physiological limits of the frequency ranges of the songs, their duration and the depth at which the whales can emit them.
These vocalizations would thus be located mainly at the same depths and frequencies as the sounds produced by maritime traffic, disrupting a possible communication between cetaceans.
