Scientists have analysed a hole in the fossil skull of a large Triceratops and concluded that the injury was caused by another Triceratops. This study suggests that Triceratops engaged in fights with other members of their species (intraspecific combat).
A specimen of Triceratops (T. horridus) referred to as Big John was discovered in 2014 in the Upper Cretaceous Hell Creek Formation (Montana, USA). There is a hole (fenestra), in the right squamosal. The neck shield is perforated and researchers from the University of Chieti-Pescara, the University of Bologna in collaboration with other research institutes conducted detailed tests on the fossilised bone surrounding this perforation.
Extracranial fenestrae in ceratopsian neck frills had been interpreted as evidence of injuries that resulted from intraspecific combat. To evaluate this hypothesis the researchers conducted extensive tests on the fossil bone immediately surrounding the hole in the neck frill. Microscopy analysis revealed newly formed and healing bone, with histological signs typical of the bone remodelling phase associated with recovery from an injury. In addition, chemical analysis revealed typical signatures associated with bone re-growth and healing.
The researchers conclude that histological and microanalytical analyses indicate that the squamosal fenestra of Big John is the result of a traumatic event, which might indeed have occurred during a fight with another Triceratops.
The scientific paper: “Histological and chemical diagnosis of a combat lesion in Triceratops” by Ruggero D’Anastasio, Jacopo Cilli, Flavio Bacchia, Federico Fanti, Giacomo Gobbo and Luigi Capasso published in Scientific Reports.