Sorry, Hollywood: scientists are back to dispel yet another one of your misconceptions about T. rex. Though modern renditions of our “tyrant lizard king” often depict the carnivorous dino with a gaping maw, fearsome teeth and flapping tongue, new research suggests that the T.rex couldn’t move its tongue much at all, as Nicola Davis reports for the Guardian. (The T. rex's terrifying mouth and chompers still hold up to scrutiny.)
Most dinosaurs, in fact, may have had tongues that were rooted to the floors of their mouths. Researchers at the University of Texas at Austin and the Chinese Academy of Sciences examined more than 330 fossil specimens, including small bird-like dinosaurs, large plant-eating dinosaurs, flying pterosaurs and a Tyrannosaurus rex. More specifically, the scientists studied the dinosaurs’ delicate hyoid bones, which anchor the tongue to the mouth.
The team then used dissection and high-resolution images to examine the hyoid muscles and bones of 15 modern animals related to dinosaurs, among them three alligators and myriad bird species ranging from ostriches to ducks, according to a statement issued by the University of Texas at Austin. Researchers compared the dinosaurs’ hyoids to those of modern specimens, and published their findings this week in the journal PLOS One.
Most of the dinosaurs the team studied had short and simple hyoids, similar to those of alligators and crocodiles. As Davis explains in the Guardian, alligators and crocs have a “tear and gulp” approach to eating their food; they don’t chew much, and therefore don't need a particularly long or mobile tongue. The tongues of the T.rex and other dinosaurs were likely similarly short and simple.
Birds, by contrast, have very diverse and complex tongues. “We take birds for granted, but they have crazy tongues,” Julia Clarke, a paleontologist at Austin and one of the authors of the study, tells Davis. “The way that tongue is able to protrude so far is that these little skinny bones are super, super long – they are so long that in a hummingbird they wrap over the surface of the skull into the nose holes.”
The researchers found that bird-like dinosaurs and pterosaurs (which, remember, aren't dinosaurs but prehistoric reptiles) also had complicated tongue bones, which led them to posit that the evolution of diversity and mobility in tongues might be connected to flight. When ancient creatures’ hands evolved into wings, they needed mobile tongues so they could better manipulate food. As Theresa Machemer of National Geographic points out, flight may have also allowed dinosaurs to access different kinds of food, which required specialized tongues and mouths.
But flight may not have been the only factor influencing the mobility of dinosaurs’ tongues. Ornithischians, an herbivorous group of dinosaurs that includes the triceratops, also had complex hyoids—perhaps because they needed to chew their food more than dinosaurs like the T.rex.