What made Triceratops so horny?

Horn-faced dinosaurs like Triceratops had elaborate frills and spurs that adorned their skulls and grew more elaborate—and diverse—through the eons. Later species, such as Chasmosaurus belli (above), sported frills that were up to a meter long. Paleontologists have floated several ideas about what spurred the evolution of such elaborate headgear. Recently, some have suggested it might have been a way to communicate with other dinosaurs, helping them recognize members of their own species.

To test whether species recognition was the driving force behind the adornments, scientists examined whether horn-faced species that shared territory also had more distinct ornaments. They compared 350 different characteristics in 1035 different species pairs. Thirty-eight of the pairs existed at the same time in the same region, and 63 more lived at the same time on the same continent, though their fossils have not ever been found together in the same area. The researchers found no evidence that any of the pairs were more distinct from each other than pairs that came from different eras or completely different regions.