New Study on Ceratopsian Skull Injuries indicates that Horns were used as Weapons
Palaeontologists have debated for many years as to what were the exact function and purpose of the horns and frill on horned dinosaurs such as Triceratops. Now a new study undertaken by American scientists has concluded that the horns on dinosaurs such as Triceratops were used as defensive weapons and wielded in battles with rivals. The scars and damaged bone found on the skulls of these dinosaurs reveal rare evidence of dinosaurs fighting each other the scientists have stated.
Andrew Farke, curator at the Raymond M Alf Museum of Palaeontology, in Claremont, California said:
“Palaeontologists have debated the function of the bizarre skulls of horned dinosaurs for years now. Some speculated that the horns were for showing off to other dinosaurs, and others thought that the horns had to have been used in combat against other horned dinosaurs. Unfortunately, we can’t just go and watch a Triceratops in the wild.”
After studying a number of different skull specimens (fortunately, Triceratops skulls are relatively numerous in the fossil record, compared to other bones from these creatures), examining the fossilised bone for signs of traumatic injury; the team reported their findings in the journal the Public Library of Science One.
Triceratops is one of the most famous dinosaurs of all, partly because it has been depicted in many films and television programmes fighting predators such as Tyrannosaurus rex. This new research indicates that the script writers and production team may have got it right when they depict this six tonne dinosaur in combat with meat-eating dinosaurs. Traces of blood vessels found in the frill and horn have indicated that these adornments may have been used for display or for regulating the temperature of these large four-legged animals. As with other members of the ceratopsian family, the frill would have probably been covered with skin and may have been brightly coloured, suggesting that it was used for display purposes.
A study by British scientists some years ago concluded that dinosaurs like Triceratops may have locked horns with opponents but not charged at them like a rhinoceros. The impact forces from a 9 metre long, six tonne monster would have shattered the nasal and rostrum – not a particularly good outcome for the horned dinosaur.
The American team studied the skulls of Triceratops and compared them with the skulls of another ceratopsian called Centrosaurus. Triceratops had three horns, two large brow horns, in some specimens over a metre long, and a shorter nose horn. In contrast Centrosaurus (Centrosaurus apertus), had just one prominent horn, the nose horn. From studies of the numerous centrosaurine skulls found at the Dinosaur Provincial Park Formation in Alberta, scientists believe that juvenile centrosaurs possessed a short, narrow horn. As the centrosaurs reached adult size, and presumably were able to breed, the nasal horn developed into a robust, long horn and parts of the skull became thicker and stronger.
The Two Horned Dinosaurs used in the Study (Triceratops and Centrosaurus)
Picture Credit: Everything Dinosaur
In the picture above, the three-horned Triceratops is depicted on the left with the Centrosaurus with its large nasal horn on the right.
The Triceratops is the “Triceratops with attitude” from the Procon/CollectA range and the Centrosaurus is one of the dinosaur models from our party models collection.
To view Triceratops and other horned dinosaurs: Dinosaur and Prehistoric Animal Models.
The injuries seen in Triceratops skulls were consistent with combat injuries, perhaps as rivals battled with each other over social status in the herd. Centrosaurus skulls did not show similar injuries indicating that their horns and frill were perhaps used more for display. Interestingly, a number of centrosaurine bone beds are known. A bone bed is a deposit of a large number of fossilised bones representing many individuals of a single species. Such bone beds are evidence that dinosaurs moved in large herds, perhaps a number of the herd members met their death at the same time, for example, fording a river, much in the same way that many gnu die when crossing flooded rivers in Africa.
From this fossil evidence scientists have concluded that Centrosaurus lived in large groups, whereas no such bone bed evidence has been found to date for Triceratops. It can be speculated that Triceratops lived in much smaller groups, if this is the case then combat could be envisaged when males were seeking mates as the herd structure being smaller would have led to battles only occasionally. In contrast, if Centrosaurus lived in large groups, using facial ornamentation for display would make a lot of sense as in a large herd the chances of combat would be higher as more animals of near rank and size would be in close proximity to each other.
Dr Farke added: “If Triceratops and Centrosaurus only used their horns and frills for showing off, we would expect no difference in the rate of injury for both animals. The most likely culprit for all of the wounds on Triceratops frills was the horns of other Triceratops”.
The team went onto compare the horns of Triceratops with a Swiss Army knife, suggesting that the horns may have been used for a variety of purposes, combat, ritual display and for defence against predators. Skulls of ceratopsians had been studied in detail before, but this study looked at a huge number of different specimens and looked for similarities in the injuries they found and modelled how these wounds could have been caused.
The injuries seen on the Triceratops fossils were consistent with the animals battling one another and fighting with their horns. Centrosaurus, however, showed no such pattern, suggesting that its facial adornments were more for display.
“If Triceratops and Centrosaurus only used their horns and frills for showing off we would expect no difference in the rate of injury for both animals”.
Concluded Dr Farke.
One particular injury, of the squamosal bone on the frill, (top and back of the skull), was ten times more frequent in Triceratops than in Centrosaurus.
Dr Farke went on to add:
“Our findings provide some of the best evidence to date that Triceratops might have locked horns with each other, wrestling like modern antelope and deer. This suggests that the animals, principally males, sparred for dominance and access to mates. Many modern herbivores with antlers or horns do this”.
A fellow contributor to the study, Ewan Wolff of the University of Wisconsin-Madison stated that this was the most comprehensive assessment of ceratopsian combat yet. The conclusions have been compiled from an extensive study of a number of different specimens, allowing close comparisons between individuals to be made.
Ewan Wolff went on to state:
“In the past, individual remains have been used to reconstruct the story of ancient injuries. I think this research shows the great potential of looking at injury patterns, even less obvious ones, to provide appropriate conclusions. The features we studied were very subtle”.