Life-Sized Cast of Triceratops horridus Skeleton Acquired
as the Latest Addition to Our Permanent Collection

The Cleveland Museum of Natural History has acquired a 21-foot-long, full-sized replica of a Triceratops dinosaur that lived during the Late Cretaceous period, from 68 million to 65 million years ago. The skeleton cast will be on permanent display in the Museum's Kirtland Hall of Prehistoric Life. This exhibit has been made possible by The William J. and Dorothy K. O'Neill Foundation.

Triceratops horridus

Location: Kirtland Hall

Triceratops lived during the Late Cretaceous Period, 68 million to 65 million years ago. It was one of the biggest dinosaurs of its time, second only in size to its arch-enemy, Tyrannosaurus rex.

The Museum’s Triceratops is a replica of a mount on display at the American Museum of Natural History. It was created by the Canadian museum-exhibit fabricators Research Casting International.

The original mount is a composite of four fossil specimens found in Wyoming and Montana in 1909 by George Sternberg, Barnum Brown and Peter Kaisen. Some parts of the mount were modeled after other Triceratops bones in the AMNH’s collections.

No complete Triceratops skeletons are known, which is why museums have to mount composite skeletons for display. Unlike some horned dinosaurs that are found together in large groups, Triceratops fossils are only found as isolated specimens. This suggests that Triceratops may have lived a solitary lifestyle, as do most rhinos today.

Triceratops was one of the last dinosaurs to evolve at the end of the Cretaceous Period before all the dinosaurs (except birds!) went extinct 65 million years ago. Triceratops specimens have been found in Colorado, Montana, South Dakota, Wyoming, Alberta and Saskatchewan.

At this time, there were many fewer types of dinosaurs than there had been even 10 million years earlier – probably fewer than two dozen different types in western North America. Triceratops would have lived in a time of a cooling climate as the inland sea that covered much of interior of North America during the Cretaceous drained away.

The genus Triceratops was once divided into as many as 16 species. However, recent research has reclassified those into just two species, Triceratops horridus and Triceratops prorsus. The Museum’s mount is that of T. horridus.

This exhibit has been made possible by The William J. and Dorothy K. O'Neill Foundation.

A Body Eclectic
The genus Triceratops as a whole was the largest of the horned dinosaurs (ceratopsians). Its members ranged between 20 and 28 feet long and 10 feet tall (the Museum’s mount is 21 feet long). Their skulls alone were often 9 feet long. In life, a typical Triceratops probably weighed about 5 tons.

The genus Triceratops as a whole was the largest of the horned dinosaurs (ceratopsians). Its members ranged between 20 and 28 feet long and 10 feet tall (the Museum’s mount is 21 feet long). Their skulls alone were often 9 feet long. In life, a typical Triceratops probably weighed about 5 tons.

Triceratops’ jaws narrowed into a parrot-like beak, a feature unique to ceratopsians. Its eyes were widely spaced so that it could take in a broad view of its surroundings.

One of the defining characters of dinosaurs is that they hold their legs under their bodies. Some dinosaurs, such as Triceratops, had a modified version of this stance due to the shape of their bodies. Triceratops held its hind limbs vertically under its hips, but because of its barrel-shaped chest, it held its upper arm bone (humerus) out from and horizontal to its body.

Triceratops Skull
Triceratops horridus “Horrible Three-Horned Face” Age: Late Cretaceous, 68-65 million years ago Length: 21 feet; Living weight, approximately 5 tons Collected by: George Sternberg and P.C. Kaissen in 1909 Found in the localities of: Seven Mile Creek and Niobrara County, Wyoming; and Sand Creek, Montana Composite skeleton of AMNH 5116/75039

My, What Big Horns You Have!
Triceratops had a short horn on its nose and two long brow horns. (Its genus name means “three horned face.”)

Triceratops’ horns were solid bone for most of their length, with a covering of keratin (the same substance that forms your fingernails) that may have doubled their length. Sinuses at the base of each horn may have functioned as shock absorbers.

The horns would have made formidable defensive weapons against a hungry T. rex. They may also have been used like those of modern deer and sheep. The males of these animals will often battle each other with antlers or horns to determine who will get the right to mate. And so it may have been that the Triceratops with the largest horns produced the most offspring.

Nothing Silly About That Frill
Triceratops had a broad, saddle-shaped frill projecting from the back of its skull. Frill shape is one of the characteristics that paleontologists use to divide genera and species between the two subfamilies of ceratopsians: centrosaurines and chasmosaurines.

Centrosaurinae ceratopsids typically had short horns over their eyes, long horns over their noses and spikes or hooks on the margins of their frills. Chasmosaurinae ceratopsids usually had long horns and relatively plain neck frills. Triceratops was a chasmosaurine.

Paleontologists have several idea