Triceratops horridus
Triceratops horridus was one of the last and largest of all horned dinosaurs. It reached about 8–9 metres in length and weighed somewhere between 6 and 12 tonnes, roughly the mass of two African elephants.
Triceratops
Triceratops horridus
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Weight
6000–12000 kg
Length
7.9–9 m
Diet
Herbivore
Period
Cretaceous
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Triceratops next to Tyrannosaurus rex and a human, to the same scale.
Triceratops horridus
Tyrannosaurus rex
6000–12000 kg
7.9–9 m
Cretaceous
Quadrupedal
2.4–3 m
25 km/h
Herbivore
41 recorded fossil finds in United States and Canada. Most in Wyoming, Montana, and South Dakota. First described in 1889 by Marsh.
Sites and counts from the Paleobiology Database
The timeline shows the whole age of dinosaurs – and how much time has passed since. The glowing part is when Triceratops lived.
million years ago
Lived 68–66 million years ago
If the whole age of dinosaurs were a single day, Triceratops lived at 23:52.
Chapter • Meet the dinosaur
Triceratops horridus was one of the last and largest of all horned dinosaurs. It reached about 8–9 metres in length and weighed somewhere between 6 and 12 tonnes, roughly the mass of two African elephants. Its most striking feature was its enormous head: the skull could exceed 2 metres in length, making it one of the biggest skulls of any land animal ever discovered. Two long brow horns rose above the eyes and could approach a metre in length, while a shorter horn sat on the snout. Behind them rose a solid bone frill that shielded the neck. The body was barrel-shaped and heavily built, the limbs were held beneath the body, and the tail was carried clear of the ground rather than dragging behind. Skin impressions show a covering of coarse, hexagonal scales, and some researchers have suggested that certain large scale bosses may have supported bristle-like structures similar to those of its distant relative Psittacosaurus.
Chapter • Where it lived
Triceratops lived at the very end of the Cretaceous, during the Maastrichtian stage roughly 68–66 million years ago, in western North America. The landscape was a warm, humid coastal lowland of broad floodplains, river deltas, swampy forests and open glades along the shrinking Western Interior Seaway. Conifers, cycads and ferns grew alongside a rapidly expanding flora of flowering plants. Fossils come mainly from the Hell Creek Formation of Montana and the Dakotas, the Lance Formation of Wyoming, the Denver Formation of Colorado and the Frenchman Formation of Saskatchewan, Canada. Triceratops is one of the most abundant fossils in Hell Creek, with hundreds of individuals excavated, making it one of the best-known dinosaurs of all.
Chapter • Wild behavior
Diurnal
The name Triceratops means roughly "three-horned face" in Greek.
Its skull could exceed 2 metres in length — nearly a third of the animal's entire body length.
The very first find, a pair of horns from 1887, was mistakenly described as belonging to a giant extinct bison.
Fossils show healed injuries on frills and horns that match bite marks from Tyrannosaurus rex, an animal it shared its world with.
Triceratops carried up to 800 teeth arranged in dental batteries that were continuously replaced.
Some researchers proposed that Torosaurus was simply a fully mature Triceratops, but most palaeontologists today keep them as separate genera.
Horn shape changed with age: juveniles had short, backward-curving horns that straightened as the animal grew.
Triceratops was among the very last dinosaurs alive before the mass extinction 66 million years ago.
Chapter • Scientific place
Journal of Vertebrate Paleontology
Reviewed: 9/3/2026
Peer-reviewed revision placing Triceratops within Ceratopsidae (Chasmosaurinae) and clarifying the genus' species-level taxonomy and synonymy.
Open sourceProceedings of the National Academy of Sciences (PNAS)
Reviewed: 9/3/2026
Documents the stratigraphic and geographic distribution of Triceratops specimens through the Hell Creek Formation of Montana, western North America.
Open sourcePaleobiology Database
Reviewed: 9/3/2026
Compiles the fossil occurrences of Triceratops horridus with their host formations, Maastrichtian ages and terrestrial/fluvial depositional environments.
Open sourceScience Advances
Reviewed: 9/3/2026
Analyses the tooth microstructure and wear of Triceratops, showing a slicing dentition adapted to processing tough plant material (herbivory).
Open sourceBiology Letters (Royal Society)
Reviewed: 9/3/2026
Extinct taxon; conservation status NE
Open sourceNatural History Museum, London
Reviewed: 9/3/2026
Museum overview of Triceratops covering its size, horned skull and frill, age and North American occurrence, used as the basis for the sv/en/da/no description texts.
Open sourceNatural History Museum, London
Reviewed: 9/3/2026
Museum overview of Triceratops covering its size, horned skull and frill, age and North American occurrence, used as the basis for the sv/en/da/no description texts.
Open sourceNatural History Museum, London
Reviewed: 9/3/2026
Museum overview of Triceratops covering its size, horned skull and frill, age and North American occurrence, used as the basis for the sv/en/da/no description texts.
Open sourceNatural History Museum, London
Reviewed: 9/3/2026
Museum overview of Triceratops covering its size, horned skull and frill, age and North American occurrence, used as the basis for the sv/en/da/no description texts.
Open source
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