Triceratops: the three-horned face of the Hell Creek

When and where

Triceratops lived during the last 2 million years of the Cretaceous, between 68 and 66 million years ago. Its range covered Laramidia, the western half of a North America split by the Western Interior Seaway. Fossils turn up across Montana, Wyoming, the Dakotas, Saskatchewan, and Alberta, with the Hell Creek and Lance formations producing the highest specimen counts. Triceratops was a contemporary of Tyrannosaurus rex, and the two genera are both among the very last large dinosaurs alive when the Chicxulub impact closed the Mesozoic.

How we know

Othniel Charles Marsh named Triceratops horridus in 1889, working from a pair of horn cores found near Denver and originally mistaken for an extinct bison. Marsh recognised the cores as ceratopsian and erected the genus a year later. More than 50 partial Triceratops skulls have been recovered since, more than for almost any other large dinosaur, partly because the heavy fused skull preserves well even when the rest of the skeleton scatters. A second species, Triceratops prorsus, is now widely accepted, distinguished by skull proportions and horn angle. Source: Wikipedia entry on Triceratops.

What set it apart

The skull tells the whole story. Triceratops carried two long brow horns, each reaching 1 metre in adult specimens, plus a shorter nose horn, all set behind a wide parietal frill that extended back over the shoulders. The frill was solid bone, unlike the holes-in-the-frill design of Pentaceratops and Chasmosaurus, suggesting it functioned as a defensive shield rather than a display screen alone. Behind the head, the body was barrel-shaped, with four short pillar-like legs supporting roughly 5 to 9 tonnes. Length came in at 8 to 9 metres. Adult skulls reached 2 to 3 metres long on their own, among the largest in any land animal that has ever lived. Tooth batteries packed hundreds of replacement teeth into shearing rows for slicing through tough Cretaceous palms and cycads.

For collectors and classrooms

A scaled Triceratops figurine carries the iconic silhouette into a classroom or display shelf. Look for a model with proportional horns and a frill that sits behind the head rather than upright like a fan. Browse a hand-painted figurine.