Study firms up idea that triceratops used horns in duels with rivals

Because nobody was around to witness their use, the functions of the impressive horns and frill of the familiar dinosaur triceratops have been a matter of speculation.

But a new study, conducted in part by a student at the School of Veterinary Medicine, reveals that the beast routinely used its horns in combat with rival triceratops, much as contemporary animals like deer and moose lock horns in violent competition for mates.

“There are a lot of theories about how these structures might have been used,” explains Ewan Wolff, a co-author of the study published Jan. 28, 2009 in the online journal Public Library of Science.

Notions of how and why the triceratops deployed its massive headgear include defense against predators, for display in mating rituals or competitions, and for intraspecies combat over mates or turf. But all of those theories, notes Wolff, lacked supporting evidence until now.

Wolff and his colleagues, Andrew Farke of the Raymond M. Alf Museum of Paleontology in Claremont, Calif., and Darren H. Tanke of the Royal Tyrrell Museum of Paleontology in Drumheller, Alberta, scoured North American museum collections in search of the telltale evidence of facial wounds suffered by the horned animals, which could grow to 26 feet in length and weigh in at seven tons.

“This was a very extensive survey. We really did try to look at all the specimens that are out there,” says Wolff, who trained as a paleontologist and specializes in paleopathology. “What surprised us was that we were able to go in and look at very small features in a lot of different specimens and begin to see that the pattern was non-random.”

The pattern that emerged, according to a statistical analysis of the wounds found on 186 samples, strongly implies that triceratops used its horns to duel with rivals and its frill as a shield to protect vital organs in what must have been bruising contests that left many animals with bony skull lesions, some of which would salt the paleontological record.

For Wolff, the excitement of the paper lies in the coupling of museum specimen analysis of pathology and statistics, which can yield insights into the behaviors of animals that no human ever set eyes upon. “This shows the potential of paleopathology for understanding the paleobiology of animals.”