A violent encounter with a rival dinosaur may explain why Big John, the most massive Triceratops skeleton ever found, has a keyhole-shaped opening on its frill, a new study finds.
This fight happened more than 66 million years ago, but scientists think they know the assailant's identity: It was likely another Triceratops, according to the study, published online Thursday (April 7) in the journal Scientific Reports(opens in new tab).
"The location, shape and size of the lesion suggest that it was caused by the horn of another Triceratops of similar size," study lead researcher Ruggero D'Anastasio, a professor of biological anthropology at G. d'Annunzio University of Chieti-Pescara in Italy, told Live Science in an email.
