University Researchers Trace Bird Vocalization to Cooing Dinosaurs
The three Jurassic Park movies in the late 1990s and early 2000s showed fans a roaring T-Rex and a dangerous Indominus Rex in the most recent 2015 film in the franchise, Jurassic World.
While most people think of roaring as a dinosaur trait, professors from the University of Texas, Midwestern University, Memorial University of Newfoundland, and the University of Utah had been conducting a study on birds and reptiles, and how their close-lipped vocalization had evolved.
This meant diving into past studies on dinosaurs.
The study “Coos, booms, and hoots: the evolution of closed-mouth vocal behavior in birds” is posted online in the science journal, Evolution, and will be printed later in the August issue.
This stemmed from the question of how bird vocalization evolved.
The closed-mouth (or closed-beak) vocalization happens when birds produce sounds that pass through the skin in the neck area while their beaks are still closed.
Birds do this by pushing air through an esophageal pouch.
This is how birds produce their cooing sounds. Now imagine that several avian and reptilian pre-historic creatures did those, too.
The university researchers conducted a study that would allow them to statistically identity the distribution of closed-mouth vocalization among birds and reptiles.
They found out that 52 bird species (out of the 208 they investigated) used such vocalization.
One of the researchers, Chad Eliason from the University of Texas Jackson School of Geosciences, said that their results could help other scientists study deeper into how dinosaurs used sounds to communicate.
Eliason also said that their research revealed that the closed-mouth vocalization had evolved 16 times in archosaurs (a group that includes birds, crocodiles, and all extinct dinosaurs), and that only those that are the size of a dove or larger could produce such sounds.
This matter of sound and size is, according to another researcher, Tobias Riede, about physics. Riede is a physiology professor at the Midwestern University and he said,
“The lung pressure required to inflate a cavity depends on the tension in the wall of the cavity, and this tension increases for smaller body sizes.”
This means that large dinosaurs could possibly have produced closed-mouth sounds.
Although their results don’t paint a definitive picture of dinosaurs cooing like birds, the fact that closed-mouth vocalization occurs in the surviving members (birds and crocodiles) of the archosaurs and that it had evolved many times during the years means that there is a great possibility that such vocal phenomenon had also occurred during the age of the dinosaurs.
Another professor from the Jackson School of Geosciences, Julia Clarke, said that the key to understanding how extinct dinosaurs communicated through sounds was to turn their attention to living species of birds.
There have been many new revelations in the study of dinosaurs, including the fact that many dinosaurs had feathers, something that has not yet been translated or adapted much into mainstream media.
If such a discovery is possible, though, then it isn’t far from imaginable that dinosaurs, instead of just roar, could also make low, cooing sounds for various communication reasons.