Study aims to determine if ancient dinosaurs really could roar

Thanks to movies like Jurassic Park we all think of dinosaurs as having incredibly loud roars. Scientists aren't sure if the actual dinosaurs that these movies aim to represent could roar. The reason for this is that it is incredibly hard to find ancient dinosaur voice boxes because they didn't fossilize well. What dinosaurs would have used to make vocalizations would have been one of two different structures called a larynx or a syrinx. Most living land-dwelling vertebrates today use a larynx to vocalize, this is a structure mostly made of cartilage that makes sounds at the back of the mouth.

Birds on the other hand have a syrinx which is a structure that sits at the base of the windpipe and is more sturdy than a larynx. So far paleontologists have discovered a few dinosaur larynx fragments, but there is no definitive proof that the dinosaurs could vocalize. Finding a fossilized syrinx though would indicate that the animals could vocalize because that structure is only used for sound production.

A fossilized syrinx was discovered back in 2013 as part of a duck-like skeleton which had been found in Antarctica a decade before being studied. This particular animal lived 66 to 68 million years ago. Scientist Julia Clarke from UT Austin discovered the syrinx while performing a CT scan on the duck-like skeleton. The discovery led Clarke to theorize that older and more primitive syrinxes must have existed. She says that the specimen suggests that the shape of the syrinx would have supported two sounds. Modern ducks can quack and make a whistling sound for instance.

This fossil helps shed some light on what dinosaur might have sounded like, or might not have sounded like. Clarke figures that since the syrinx can fossilize that the lack of syrinx fossils discovered in dinosaur fossils so far suggest the creatures lacked this structure. This leads Clarke and other scientists on the project to think that ancient dinosaurs might have vocalized more like modern crocodiles. Clark believes that the dinosaur vocalizations might have consisted of "low-frequency booms, maybe using a resonating structure such as an inflated esophagus or something like that, and using the larynx, not a syrinx."