FRANCE: Humans and birds have separately developed the same musical solution to talking and singing, an evolution study has found.
Both employ a system that involves sound pulses being generated hundreds or thousands of times per second as folds of tissue rapidly vibrate.
The “myoelastic-aerodynamic” theory (Mead) was first proposed in the 1950s to explain the way vocal cords in the larynx oscillate to create sound.
Now new research suggests exactly the same mechanism is employed by both humans and birds, despite them having completely different vocal organs.
“Science has known for over 60 years that this mechanism … drives speech and singing in humans,” says lead scientist Dr Coen Elemans of the University of Southern Denmark.
“We have now shown birds use the exact same mechanism to make vocalisations. Mead might even turn out to be a widespread mechanism in all land-dwelling vertebrates.”
A bird’s vocal organ, the syrinx, is buried deep inside the breast cavity near the lungs, making it difficult to study. Instead of having vocal cords, its walls are lined with drum-like elastic membranes that vibrate in response to flowing air.
Dr Elemans’ team, whose findings are reported in the journal Nature Communications, studied six different species of bird from the tiny zebra finch to the huge ostrich.
Using high speed cameras, the researchers showed all of them produced sound according to the Mead theory.
“To me it was very surprising and fascinating to discover that such different vocal organs make sound the same way,” says co-author Dr Jan Svec from Palacky University in the Czech Republic.
Elemans adds that Songbirds are an excellent model to study the human voice and its neurological diseases, “so we hope to transfer our knowledge about songbird vocal production to research in human vocal production”.
