ABSTRACT
Triceratops, a common chasmosaurine ceratopsid dinosaur from the Late Cretaceous of North America, is known for its cranial ornamentation, including a single nasal horn and large, paired supraorbital horns. It is commonly surmised that Triceratops used its horns in intraspecific combat, but this hypothesis has not been rigorously tested. Scale models of Triceratops skulls were used to determine if it could physically lock horns as has been suggested. Three hypothetical horn locking positions were found, involving varying orientations of the combatants' skulls. Based on these positions, it was hypothesized that injuries caused by horns were especially likely in certain portions of the frill, jugals, and postorbital horncore tips. This corresponds to some previously reported pathologies in chasmosaurine specimens. Uncertainties in this modeling exercise center around variations in horn orientation, size, shape, and the possible existence of a keratinous supraorbital horncore sheath. Triceratops differs from modern horned mammals in its horn orientation, which suggests that if it engaged in intraspecific combat, its fighting style was quite different from these modern animals. During hypothetical horn locking in Triceratops, most of the force was directed against the medial and lateral surfaces of the horn cores. This has implications for future studies of ceratopsid cranial functional morphology, especially as related to horn architecture and the development of the frontal sinus complex.
Andrew A. Farke. Department of Anatomical Sciences, Stony Brook University, Health Sciences Center, Stony Brook, New York, 11794-8081, USA.
KEY WORDS: Ceratopsidae, Chasmosaurinae, dinosaurs, horn use, paleopathology, Triceratops
Copyright: Society of Vertebrate
Paleontology. June 2004
Submission: 9 December 2003. Acceptance: 1 April 2004.
