Beaks Aren't Just for the Birds: Importance Behind Dinosaur Beaks Revealed

Birds aren't the only ones with beaks. Dinosaurs also possessed this adaptation. Now, scientists are investigating these features a bit more closely, trying to find out why beaks evolved in some theropod dinosaurs and not in others.

During the Cretaceous Period, keratin-covered beaks had already evolved in different groups of dinosaurs. In order to better examine this adaptation, though, the researchers looked at the skull of Erlikosaurus andrewsi, a 10 to 13 foot-long herbivorous dinosaur commonly called a therizinosaur. This animal lived more than 90 million years ago in what is now Mongolia and had a keratinous beak covering part of its snout.

In order to get a better view of how this beak and skull acted during the dinosaur's lifetime, the researchers used a computer modeling technique routinely used in engineering--Finite Element Analysis. This allowed them to see how bite and muscle forces affected the skull during the feeding process.

So what did they find? It turns out that the keratinous beaks played an important role in stabilizing the skeletal structure during feeding. The beak actually made the skull less susceptible to bending and deformation. In other words, it's all a matter of physics.

"It has classically been assumed that beaks evolved to replace teeth and thus save weight, as a requirement for the evolution of flight," said Stephen Lautenschlager, one of the researchers, in a news release. "Our results, however, indicate that keratin beaks were in fact beneficial to enhance the stability of the skull during biting and feeding."

The findings reveal that beaks evolved in order to provide extra stabilization to the skull. In this case, the researchers showed that, at least for this dinosaur, the beak adaptation was crucial for feeding and biting.

"Beaks evolved several times during the transitions from dinosaurs to modern birds, usually accompanied by the partial or complete loss of teeth, and our study now shows that keratin-covered beaks represent a functional innovation during dinosaur evolution," said Lawrence Witmer, one of the researchers, in a news release.

The findings are published in the journal Proceedings of the National Academy of Sciences.