Pentaceratops sternbergii
Pentaceratops sternbergii was a heavily built plant-eater that carried one of the largest heads ever seen on a land animal. The body reached roughly 5.5–6 metres in length and weighed an estimated 2.5–5.5 tonnes, but the skull is the real showpiece: including the neck frill it could measure around 2.5 metres.
Pentaceratops
Pentaceratops sternbergii
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Weight
2500–5500 kg
Length
5.5–6 m
Diet
Herbivore
Period
Cretaceous
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2500–5500 kg
5.5–6 m
Cretaceous
Quadrupedal
2–2.6 m
25 km/h
Herbivore
6 recorded fossil finds in United States. Most in New Mexico and Colorado. First described in 1923 by Osborn.
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 Pentaceratops lived.
million years ago
Lived 76–73 million years ago
If the whole age of dinosaurs were a single day, Pentaceratops lived at 22:54.
Chapter • Meet the dinosaur
Pentaceratops sternbergii was a heavily built plant-eater that carried one of the largest heads ever seen on a land animal. The body reached roughly 5.5–6 metres in length and weighed an estimated 2.5–5.5 tonnes, but the skull is the real showpiece: including the neck frill it could measure around 2.5 metres. The animal had a powerful parrot-like beak, a horn on the nose and two long brow horns above the eyes. The two extra "horns" behind the name are in fact enlarged cheekbone (jugal) spikes, a feature shared by all ceratopsids. The frill was pierced by two large openings that were covered by skin and muscle in life, keeping the head surprisingly light, and its margin was lined with a row of bony scallops. At the top the frill bore a deep notch flanked by two forward-pointing prongs, a signature feature that separates Pentaceratops from its relatives. It walked on all fours, with strong hind limbs, slightly bowed forelimbs and a tail carried clear of the ground.
Chapter • Where it lived
Pentaceratops lived roughly 76–73 million years ago, during the Campanian stage of the Late Cretaceous, in what is now the San Juan Basin of north-western New Mexico, USA. The fossils come mainly from the Fruitland and Kirtland formations, sediments laid down on humid coastal lowlands along the western shore of the Western Interior Seaway. The landscape was a mosaic of meandering rivers, swamps, lagoons and stands of conifers, palm-like plants, ferns and early flowering plants, under a warm, seasonally wet climate. It shared this world with duck-billed dinosaurs, armoured dinosaurs and tyrannosaurids such as Bistahieversor.
Chapter • Wild behavior
Diurnal
Most Pentaceratops specimens are isolated individuals, so there is no firm evidence that this particular species lived in herds. Several related ceratopsids, however, are known from bonebeds containing many individuals, suggesting that at least seasonal group living was widespread in the family. The huge frills and horns are today usually interpreted as signals for species recognition and social display rather than purely defensive gear. Healed injuries on the frills of relatives hint that individuals sometimes shoved or locked horns with one another.
The name means "five-horned face", but only three of the projections are true horns; the other two are cheek spikes found in every horned dinosaur.
The skull could reach about 2.5 metres, ranking Pentaceratops among the largest-headed land animals of all time.
Two big windows in the frill were covered by skin, effectively built-in weight saving in an otherwise enormous head.
An important skull is held at the Museum of Evolution in Uppsala, Sweden. Carl Wiman described it in 1930 as a separate species, Pentaceratops fenestratus, later shown to be the same animal as P. sternbergii.
The species name sternbergii honours fossil hunter Charles H. Sternberg, who dug up the first bones in New Mexico in the early 1920s.
A giant specimen in Oklahoma (OMNH 10165) was moved to its own genus, Titanoceratops, in 2011 — an interpretation still debated by researchers.
The jaws held dental batteries with hundreds of continuously replaced teeth, ideal for shearing tough vegetation.
Pentaceratops lived several million years before Triceratops and belonged to the same subgroup, the chasmosaurines.
Chapter • Scientific place
dinolifepedia.com
Reviewed: 9/5/2026
VERIFY:length_max_m: stored=7 suggested=6 confidence=medium — Current size estimates for P. sternbergii cluster at 5.5 m (Paul, 2016) to about 6 m (Dodson, 1996); the 6.8 m figure derives from OMNH 10165, which Longrich referred to the separate genus Titanoceratops, so 7 m overstates the confirmed maximum.
Open sourcereference.org
Reviewed: 9/5/2026
VERIFY:weight_min_kg: stored=3500 suggested=2500 confidence=medium — Paul (2016, Princeton Field Guide to Dinosaurs, 2nd ed.) estimates the mass of Pentaceratops at approximately 2.5 metric tons, so a lower bound of 3500 kg sits above the range current sources support.
Open sourcePaleobiology Database
Reviewed: 9/5/2026
Database taxon page giving the accepted classification of Pentaceratops sternbergii within Ceratopsidae (Chasmosaurinae), Ceratopsia, Marginocephalia, Ornithischia.
Open sourcePeerJ
Reviewed: 9/5/2026
Peer-reviewed study documenting the stratigraphic and geographic occurrences of Pentaceratops and related chasmosaurines in the Fruitland and Kirtland formations of the San Juan Basin, New Mexico.
Open sourcePeerJ
Reviewed: 9/5/2026
Describes the Campanian coastal-plain depositional setting of the Fruitland and Kirtland formations along the Western Interior Seaway in which Pentaceratops lived.
Open sourceNatural History Museum, London
Reviewed: 9/5/2026
Museum taxon profile identifying Pentaceratops as a herbivorous ceratopsid with a beak and shearing dental batteries for processing tough plant material.
Open sourcePaleobiology Database
Reviewed: 9/5/2026
Extinct taxon; conservation status NE
Open sourceNatural History Museum, London
Reviewed: 9/5/2026
General authoritative overview of Pentaceratops covering its size, frill and horn anatomy, age and North American distribution, used as the basis for the sv, en, da and no description texts.
Open sourceNatural History Museum, London
Reviewed: 9/5/2026
General authoritative overview of Pentaceratops covering its size, frill and horn anatomy, age and North American distribution, used as the basis for the sv, en, da and no description texts.
Open sourceNatural History Museum, London
Reviewed: 9/5/2026
General authoritative overview of Pentaceratops covering its size, frill and horn anatomy, age and North American distribution, used as the basis for the sv, en, da and no description texts.
Open sourceNatural History Museum, London
Reviewed: 9/5/2026
General authoritative overview of Pentaceratops covering its size, frill and horn anatomy, age and North American distribution, used as the basis for the sv, en, da and no description texts.
Open source