T. Rex Was a Fearsome Predator—but It Couldn't Stick out Its Tongue

Depictions of dinosaurs often show the animals baring their teeth with their tongues outstretched like lizards. However, a study published in the journal PLOS ONE indicates that this image may be inaccurate because dinosaur tongues were probably stuck to the bottom of their mouths, much like those of crocodiles and alligators today.

To make their discovery, an international team of researchers from The University of Texas at Austin (UT) and the Chinese Academy of Sciences compared the hyoid bones—bones which support the tongue—of extinct dinosaurs, pterosaurs and crocodilians to those of modern birds and crocodilians.

These animal groups, while distinct, are related, so studying them together enabled the scientists track the evolution of certain traits through time.

"Tongues are often overlooked. But, they offer key insights into the lifestyles of extinct animals," Zhiheng Li, an associate professor at the Key Laboratory of Vertebrate Evolution and Human Origins of the Chinese Academy of Sciences, said in a statement.

The comparison of the bones showed that the hyoid bones of most dinosaurs were similar to those of crocodilians in the sense that they were short, simple and connected to a tongue that couldn't move much.

According to the researchers, this means that popular depictions of dinosaurs with their tongues sticking out are not correct. The study results also provide further insights into the evolutionary history of animals.

"Our findings challenge depictions of dinosaur tongues and propose a connection on the origin of flight and an increase in tongue diversity and mobility," Julia Clarke, a professor of paleontology at UT, told Newsweek.

The scientists found that unlike crocodilians and dinosaurs with their short hyoid bones, pterosaurs (large flying reptiles which lived during the age of the dinosaurs) and birds had a much greater diversity in the shape of their hyoid bones.

This greater diversity of shapes could be linked to the ability to fly, they say, because taking to the skies may have led to new feeding behaviors that influenced how tongues evolved.

"The shifts in the tongues of pterosaurs and birds seem to go with new diets enabled by flight," Clarke said.

These shifts may be related to the gradual evolution of hands into wings, the researchers speculate: tongues may have become more important for manipulating food as species lost dexterity in their hands over millions of years. Bird tongues, for example, are remarkably adapted to specific feeding methods.