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Triceratops
The first specimen of Triceratops - originally named Bison alticornis.
Image from The Ceratopsia (1907) by Hatcher, Marsh, and Lull.
When Triceratops was first discovered, it was mistaken for a gigantic bison, and was given the name Bison alticornis by O.C. Marsh. It wasn't until more complete specimens were uncovered that Marsh realized the horn cores he'd thought were those of a mammal actually belonged to a dinosaur.
The first specimen of Triceratops - originally named Bison alticornis.
Image from The Ceratopsia (1907) by Hatcher, Marsh, and Lull.
As more examples of this animal were described it became increasingly
apparent that Triceratops was amazingly weird by today's standards. Triceratops has become such a well known dinosaur, we sometimes forget just how bizarre it really is. Consider its head: If you take an iguana's head, scale it up to be about a meter long and throw the beak of a parrot onto the front of its face, you're still nowhere near the level of bizarre that Triceratops has in store for you. Take a set of gigantic horns and place one over each of your Iguanaparrot's eyes. Now, just for good measure, throw a smaller horn over the nose. Weird. But wait - Triceratops isn't done yet. Now go to the back of your new friend's head and pull out a shelf of bone to, oh, about 2/3 the length of the rest of the head so that it forms a gigantic frill. Now the whole skull is nearly two meters in length (Triceratops got even larger than this). This isn't bizarre enough, so add some spikes to the border of the frill. And don't stop there, because you need some spikes on the cheeks too. Yes - now, cover pretty much the whole thing in keratin (the material that bird beaks and rhino horns are made of). Stand back and gaze upon what you've done to that poor iguana. That should give you just a glimpse of what Triceratops may have looked like in life.
What was Triceratops doing with all of its bizarre structures? Were epic battles between Triceratops and Tyrannosaurus rex the norm during the Late Cretaceous? Did Triceratops live in herds, like some dinosaurs are thought to have done - or was it a loner? Did male Triceratops use their horns and frills to intimidate each other and establish dominance? Was the frill a giant solar heat panel? What kind of plants did Triceratops eat? Did Triceratops mothers take good care of their babies? What color was Triceratops? If you went back in time and met a Triceratops, what would happen?
These are some of the questions you might ask if you start thinking about Triceratops. We probably won't have all of the answers until we figure out how to travel back to the Cretaceous and avoid being eaten long enough to find a Triceratops and see for ourselves. However, we can look for physical evidence and use it to devise testable hypotheses that will bring us closer and closer to understanding what Triceratops was really like. (That's how science works!)
There is so much variation between Triceratops skulls that, up until just a few years ago, it was thought that there were as many as sixteen different species of Triceratops all living together during the Cretaceous Period. In 1996, Catherine Forster published a paper in which she explained how she'd used morphometrics to determine that there were probably far fewer than sixteen species of Triceratops at the end of the Cretaceous. She found evidence for two species.
In 2006, Jack Horner and Mark Goodwin published a paper in which they describe how they'd compared several Triceratops skulls and discovered that the shape of the horns and the spikes bordering the frill changed as Triceratops grew up. Juvenile Triceratops all have backwards curving horns and triangular spikes around their frills. As Triceratops got older, its horns curved forward and the spikes on its frill became flattened. Based on this, they hypothesized that the horns and spikes were used as display structures which indicated maturity to other Triceratops. This sounds like a pretty good hypothesis to me - but it could be that juvenile trikes had backwards facing horns for some other reason. In science, you have to stick with the principle of parsimony - which basically means that you go with the simplest explanation for the data.
The Triceratops at the American Museum of Natural History. Complete skeletons of Triceratops
are actually very rare while isolated skulls are quite common. This skeleton is made up of
a number of indivduals.
are actually very rare while isolated skulls are quite common. This skeleton is made up of
a number of indivduals.
What was Triceratops doing with all of its bizarre structures? Were epic battles between Triceratops and Tyrannosaurus rex the norm during the Late Cretaceous? Did Triceratops live in herds, like some dinosaurs are thought to have done - or was it a loner? Did male Triceratops use their horns and frills to intimidate each other and establish dominance? Was the frill a giant solar heat panel? What kind of plants did Triceratops eat? Did Triceratops mothers take good care of their babies? What color was Triceratops? If you went back in time and met a Triceratops, what would happen?
These are some of the questions you might ask if you start thinking about Triceratops. We probably won't have all of the answers until we figure out how to travel back to the Cretaceous and avoid being eaten long enough to find a Triceratops and see for ourselves. However, we can look for physical evidence and use it to devise testable hypotheses that will bring us closer and closer to understanding what Triceratops was really like. (That's how science works!)
There is so much variation between Triceratops skulls that, up until just a few years ago, it was thought that there were as many as sixteen different species of Triceratops all living together during the Cretaceous Period. In 1996, Catherine Forster published a paper in which she explained how she'd used morphometrics to determine that there were probably far fewer than sixteen species of Triceratops at the end of the Cretaceous. She found evidence for two species.
In 2006, Jack Horner and Mark Goodwin published a paper in which they describe how they'd compared several Triceratops skulls and discovered that the shape of the horns and the spikes bordering the frill changed as Triceratops grew up. Juvenile Triceratops all have backwards curving horns and triangular spikes around their frills. As Triceratops got older, its horns curved forward and the spikes on its frill became flattened. Based on this, they hypothesized that the horns and spikes were used as display structures which indicated maturity to other Triceratops. This sounds like a pretty good hypothesis to me - but it could be that juvenile trikes had backwards facing horns for some other reason. In science, you have to stick with the principle of parsimony - which basically means that you go with the simplest explanation for the data.
A juvenile Triceratops skull at the Museum
of the Rockies. Juveniles all have backwards
curving horns and triangular spikes on their frills.
of the Rockies. Juveniles all have backwards
curving horns and triangular spikes on their frills.
Even though Triceratops has been known to science for 120 years, that doesn't mean that it has nothing left to teach us about the history of life on this planet. We are constantly learning new things about Triceratops and its closest relatives, the other horned dinosaurs. In early 2009, a paper in the Journal of Vertebrate Paleontology called attention to the discovery of a Triceratops bone bed - that is, a number of Triceratops all found at the same place. Many horned dinosaur species have been found in huge bone beds, suggesting that they may have lived and traveled in gigantic herds. Triceratops, on the other hand, had not been found in massive bone beds and so it was proposed that Triceratops may have lived a more solitary life. The authors of the 2009 bone bed paper hypothesized that the discovery of several Triceratops in the same area suggested that it too may have lived in herds. On top of that, based on the fact that all of the Triceratops that they had found in the bone bed were not fully mature, they speculated that Triceratops may have traveled in groups of animals of all roughly the same age.
Also in 2009, Andrew Farke, Ewan Wolff, and Darren Tanke published the results of a study on apparent pathologies (the results of disease or injury) on the skulls of Triceratops. The paper suggests that since these marks are found in consistent locations on the frills of Triceratops that it may mean that the horns and frill were not just for visual display, but may have also been used for head to head combat.
Also in 2009, Andrew Farke, Ewan Wolff, and Darren Tanke published the results of a study on apparent pathologies (the results of disease or injury) on the skulls of Triceratops. The paper suggests that since these marks are found in consistent locations on the frills of Triceratops that it may mean that the horns and frill were not just for visual display, but may have also been used for head to head combat.
Two Triceratops engaged in combat - perhaps over territory. Was this a common sight in the Late Cretaceous of North America? (artwork copyright Lukas Panzarin, used with permission).
References:
Farke AA, Wolff EDS, Tanke DH. 2009. Evidence of Combat in Triceratops. PLoS ONE 4(1): e4252. doi:10.1371/journal.pone.0004252
Forster, C.A. 1996. Species resolution in Triceratops: cladistic and morphometric approaches. Journal of Vertebrate Paleontology 16:259-270.
Hatcher, J.B., O.C. Marsh, and R.S. Lull. 1907. The Ceratopsia. US Geological Survey Monograph 49:1-300.
Horner, J.R., and M.B. Goodwin. 2006. Major cranial changes during Triceratops ontogeny. Proceedings of the Royal Society of London B. 273: 2757-2761.
Mathews, J.C., Brusatte, S.L., Williams, S.A., and Henderson, M.D. 2009. The first Triceratops bonebed and its implications for gregarious behavior. Journal of Vertebrate Paleontology 29: 286-290.
Farke AA, Wolff EDS, Tanke DH. 2009. Evidence of Combat in Triceratops. PLoS ONE 4(1): e4252. doi:10.1371/journal.pone.0004252
Forster, C.A. 1996. Species resolution in Triceratops: cladistic and morphometric approaches. Journal of Vertebrate Paleontology 16:259-270.
Hatcher, J.B., O.C. Marsh, and R.S. Lull. 1907. The Ceratopsia. US Geological Survey Monograph 49:1-300.
Horner, J.R., and M.B. Goodwin. 2006. Major cranial changes during Triceratops ontogeny. Proceedings of the Royal Society of London B. 273: 2757-2761.
Mathews, J.C., Brusatte, S.L., Williams, S.A., and Henderson, M.D. 2009. The first Triceratops bonebed and its implications for gregarious behavior. Journal of Vertebrate Paleontology 29: 286-290.
