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Dinosaurs didn't roar, they cooed, just like their bird descendants
Their bite was way worse than their bark.
There are few things as universally beloved as dinosaurs. They are often among the first fascinations a child has, and while some of our exuberance for them might fade over time, we never really stop loving them. Dinosaurs have been the focus of countless media properties including The Land Before Time and We’re Back! A Dinosaur’s Story, but no cinematic experience has more effectively captured our love of dinosaurs than Jurassic Park and the film franchise it began. (You can catch the latest addition to the Jurassic mythos in the extended edition of Jurassic World Dominion, streaming now on Peacock.)
Crafting those movies has been an exercise in mixing practical effects with computer generated imagery and sounds which nearly rivals the genetic innovation seen onscreen. While some of the dinosaurian characteristics we see in the franchise’s six films are more or less accurate, the filmmakers had to take some liberties with their portrayal, either because of some gap in our paleontological knowledge or because it just looks better onscreen. When telling big blockbuster stories, it seems, some concessions to accuracy must be made.
You might remember the roaring of the T. rex, an iconic moment from the first film in the franchise which has maintained its presence throughout. You could hear an audio clip of it now, divorced from any context, and you’d probably still recognize it right away. It feels both otherworldly and frighteningly familiar, which is a nice sweet spot for a prehistoric beast. According to the book The Making of Jurassic Park: An Adventure 65 million Years in the Making, the T. rex roar we hear in the films is a composite of vocalizations from various animals, including a baby elephant, an alligator, and a tiger. When the T. rex exhales through its nose, you’re hearing the exhalation of a whale’s blowhole.
Those roars were fabrications meant to evoke an emotion rather than accurately recreate nature. The result is incredibly effective, as evidenced by the fact that the sounds the filmmakers created are still recognizable decades after the movie’s debut. It was so effective that many people have integrated those sounds into their mental model of real world dinosaurs when the reality is a whole lot stranger.
When attempting to recreate the behavior of extinct animals, we have a handful of tools at our disposal. One of the most accessible is to compare them to similar or related animals living today. If a prehistoric creature has a common ancestry, similar morphology, lived in roughly the same environment, or filled the same niche as something alive today, we can make some inferences about how those ancient animals may have moved or hunted or interacted. Those comparisons, when not applied appropriately, can lead to the assumption that animals like the T. rex must have roared, because the apex predators we’re familiar with today roar. But that isn’t necessarily the case and might even be wholly unlikely.
In order to roar, a sort of explosive open mouthed vocalization, you need to have some kind of organ for vocalizing. In mammals and reptiles, that organ is the larynx. In birds, it’s the syrinx. Because dinosaurs exist in a sort of nebulous space between reptiles and birds, it seems reasonable to assume that they too had some organ dedicated to vocal communication, but paleontologists have never found one. Their striking absence in the fossil record of dinosaurs has left some scientists wondering if dinosaurs use vocal communication at all; and, if so, how?
The problem was further cemented in 2016 when scientists found the fossilized remains of an ancient bird, dating to the end-Cretaceous, 66 million years ago. That bird would have lived alongside the last of the dinosaurs and had a preserved syrinx. The discovery shows that the organs can preserve, making their absence in dinosaur fossils all the more curious. Unless they simply didn’t have them. One possible explanation is that the syrinx evolved relatively late in the avian lineage and the non-avian dinosaurs missed out. If that’s the case, they may have lacked the required architecture for the sorts of vocalizations we imagine or would recognize. That, however, does not mean that the landscapes of the late-Cretaceous were silent.
Hadrosaurs, for instance, may have been particularly well suited for auditory calls even without traditional vocalizing organs, thanks to the oversized crests atop their heads. Scientists have taken 3D scans of well preserved hadrosaur crests and recreated models of them. When they blew air through the crests, they created an array of sounds which rely on resonance within the chamber in lieu of vocal cords.
Of course, not all dinosaurs have crests and may have relied on other strategies for making noise. Modern birds and crocodiles both regularly produce closed mouth vocalizations which bypass the syrinx or larynx, respectively. If dinosaurs didn’t have either of those organs or some analogue, they may have relied on those closed mouth vocalizations, possibly by inflating soft tissues in their throats, the same way some birds and frogs do.
Instead of a prehistoric jungle filled with cacophonous roars and violent screams, distilling the ancient and ongoing struggle for survival into a horrifying symphony, the soundscape of the Cretaceous was likely filled with low-frequency rumblings you feel in your bones more than you hear. Were you transported back there today, much of the scuttlebutt would be beyond your capacity to hear, as massive lumbering beasts communicate in frequencies too low for humans to pick up.
That becomes especially clear when you consider the immense size of some of the dinosaurs in question. Think of how tone changes when you pull the slide out of a slide whistle. Now extend that same principle to the 10-meter or longer necks of some sauropods. Their rumbling calls were likely too low for you to hear them, but you would have felt them as they cut through the dense forests.
The soundscapes of the prehistoric ecosystem were likely filled less with roaring and screeching and more with coos and purrs as predator and prey tried desperately to communicate in any way they could, even without proper voices.
Hear the cast of Jurassic World Dominion use their highly evolved larynxes to tell you their favorite moments from the Jurassic World franchise in Jurassic Park to Jurassic World The Greatest Moments, now streaming on Peacock!