While ancient birds and dinosaurs shared the Earth at the same time, they certainly didn't sound the same.

Researchers who recently found the oldest known vocal organ belonging to a bird used the 66-million-year-old fossil to imagine what those early avian creatures sounded like. The voice box — known as a syrinx — was found inside an Antarctic fossil of a bird called Vegavis iaai that lived during the Late Cretaceous. The bird belonged to the group that includes ducks, geese and swans.

According to a release from the University of Texas Austin, where the research team was based, the syrinx is composed of stiff rings of cartilage supporting soft tissues that "vibrate to produce the complex songs and calls of modern birds." All other known examples of fossilized syrinxes have been found in birds that lived long after non-avian dinosaurs became extinct.

Due to the asymmetrical shape of the syrinx in the Vegavis iaai, researchers believe this early bird could have made honking noises using two sources capable of making sounds in the right and left parts of the vocal organ.

“We can now say that it's most probable that this bird... imitated a sound that can be compared to its living relatives, ducks and geese,” Argentine paleontologist Fernando Novas said at a news conference, reported by the Associated Press.

“The importance of this discovery is that it lets us ascertain how the dinosaurs, including birds, evolved in the way they communicated with each other and how this organ that was capable of emitting sound, permitted brain development.”

The organ's apparent absence in non-bird dinosaur fossils of the same age made researchers believe that the syrinx evolved late in the evolution of birds. Although birds are direct descendants of dinosaurs, dinosaurs were not likely able to make sounds similar to birds, the researchers said. Instead, they may have made deep, booming noises that didn't require a syrinx.

“This finding helps explain why no such organ has been preserved in a nonbird dinosaur or crocodile relative,” said Julia Clarke, a paleontologist at The University of Texas who discovered the fossil syrinx and led the analysis. “This is another important step to figuring out what dinosaurs sounded like as well as giving us insight into the evolution of birds.”

Their findings are published in the journal Nature.

Mary Jo DiLonardo Mary Jo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.