By allowing ads to appear on this site, you support the local businesses who, in turn, support great journalism.
No fearsome roar? Dinosaurs likely cooed like birds, study says
Colors show probability of each branch being an open-mouth vocalizer (blue) or a closed-mouth vocalizer (red). Pies show the probabilities that the ancestors of birds and crocodiles, palaeognath birds, and neognath birds used closed-mouth vocalization. - photo by Natalie Crofts
AUSTIN, Texas If the dinosaurs in Jurassic Park cooed instead of roared, would they be as intimidating?

Just as the movie franchise inaccurately depicts how dinosaurs look, it may also be remiss in showing the prehistoric creatures roaring, according to a new study. A team of researchers, which included members from the University of Utah in addition to the University of Texas at Austin, published a study that says dinosaurs likely communicated by mumbling or cooing with closed mouths.

To make any kind of sense of what nonavian dinosaurs sounded like, we need to understand how living birds vocalize, said Julia Clarke of the University of Texas at Austin in a statement. This makes for a very different Jurassic world. Not only were dinosaurs feathered, but they may have had bulging necks and made booming, closed-mouth sounds.

For the study, the researchers studied closed-mouth vocalization in both birds and other reptilian groups. Some birds, like doves, make sounds by pushing air through skin on their neck via an esophageal pouch instead of emitting it through an open beak, according to the University of Texas at Austin.

Looking at the distribution of closed-mouth vocalization in birds that are alive today could tell us how dinosaurs vocalized, said Chad Eliason, the studys co-author, in a statement. Our results show that closed-mouth vocalization has evolved at least 16 times in archosaurs, a group that includes birds, dinosaurs and crocodiles. Interestingly, only animals with a relatively large body size (about the size of a dove or larger) use closed-mouth vocalization behavior.

Researchers noted that while some species of birds use closed-mouth vocalization, they typically do so while defending their territory or trying to attract mates and are able to still make other sounds through their beaks. They offered the ostrich as an example of a bird that uses deep, closed-mouth vocalizations as a mating call.

The teams findings were published online by the journal Evolution and will also appear in the journals print version in August.