The story
Triceratops horridus, the three-horned face, lived about 68 to 66 million years ago in the Hell Creek and related formations of western North America. Adults were about 8 to 9 m long, with a beak, a bony frill and two horns above the eyes about a meter long. Skulls reached about 2.5 m, among the largest of any land animal. Marsh named the genus in 1889, and the collector John Bell Hatcher dug up dozens of skulls for him in Wyoming and Montana.
Triceratops belonged to the ceratopsians, a group that began as small Asian plant eaters such as Psittacosaurus, and grew large on Laramidia, the western landmass. It shared its world with Tyrannosaurus rex, and healed bite marks on Triceratops bones suggest that attacks were survived. Whether the larger-frilled Torosaurus is only an old Triceratops is debated. Triceratops was among the last non-bird dinosaurs, living until close to the asteroid impact.
Why it mattered
- Triceratops gave the public an iconic horned dinosaur and a symbol of the Late Cretaceous.
- The frill and horns are a leading example of display and combat structures in dinosaurs.
- Its abundance in the Hell Creek beds shows that dinosaurs were still thriving before the asteroid struck.
Contested history
Consensus: Triceratops is a distinct dinosaur, while the status of the related Torosaurus is argued.
Community notes
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