In popular culture, predatory dinosaurs are typically shown giving off a fearsome roar before unleashing carnage on their unsuspecting victims, but a new study indicates that they may have actually sounded quite different. According to researchers from Midwestern University in Arizona, the University of Texas at Austin, some dinosaurs would have mumbled or cooed with closed mouths, similar to how many modern-day bird species can emit sounds with their beaks shut tightly. Results of the study 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. Closed-mouth vocalizations, the study authors explained, are typically emitted through the skin in the neck region while the beak remains closed. Birds produce these noises by pushing the air which precipitates sound production into an esophageal pouch instead of through an open beak, producing a call that tends to be quieter and lower in pitch than open-mouth vocalizations http://www.redorbit.com/news/science/1113414987/dinosaurs-vocalization-071216/ Study: http://onlinelibrary.wiley.com/doi/10.1111/evo.12988/abstract
I would have suspected that the sight of a mountain of muscle, armed with nasty, sharp teeth and probably rather bad breath, would have made a terrifying roar quite redundant. Although the bright plumage that may have adorned portions of the hungry predator may have seemed a bit camp.
For some reason, a bizarre image of T Rex with a droopy moustache and wearing a leather cap and chains has swum into my brain.......
Scaling a cross between a dove's cooing and an alligator's rumble to T-Rex size would be a hell of noise, coming out of the night. I'm not sure the comparison to a mourning dove's coo is adequately suggestive.
I believe that there's evidence that some dinosaurs had large and elaborate nasal passages that extended into large crests on their skulls, that may have functioned like acoustic resonators. That suggests that they might have sounded like horns. http://www.nsf.gov/news/news_summ.jsp?cntn_id=112409&org=OLPA&from=news
Unfortunately this prompted me to compose the following, to be sung to the tune of YMCA, by The Village People: Dino, there's no need to feel down I said dino, pick yourself off the ground I said dino, 'cause you're in a new town There's no need to be unhappy Dino, there's a thing you should know I said dino, let your vocal power grow, You can let loose, and I'm sure you will find Many ways to mumble and coo! It's fun to be a big T.R.E.X. It's fun to sound like a T.R.E.X. You'll have everything for young dinos to enjoy You can mumble with all the boys. T.R.E.X It's fun to be a T.R.E.X. Repeat and fade into the KT boundary.
I always thought that roaring was implausible. It's such a mammalian form of communication - while the saurians we know are pretty quiet.
