From ThoughtCo: How Loud Could Dinosaurs Roar?

In just about every dinosaur movie ever made, there’s a scene in which Tyrannosaurus Rex lunges into the frame, opens its tooth-studded jaws at a near-ninety-degree angle, and emits a deafening roar–perhaps toppling its human antagonists backwards, perhaps only dislodging their hats. This gets a huge rise from the audience, every time, but the fact is that we know practically nothing about how T. rex and its ilk vocalized–it’s not like there were any tape recorders 70 million years ago, during the late Cretaceous period, and sound waves don’t tend to preserve well in the fossil record. Read How Loud Could Dinosaurs Roar?