Triceratops (try-SAYR-ah-tops) meaning "three-horned face", because it had three horns (Greek tri = three + keratops = horned face) was a ceratopsid herbivorous dinosaur genus from the Latest Cretaceous period of North America. It lived on the planet around 65-70 mya. It was about 9 m (30 ft) long, ten feet tall, and probably weighed around 5,400 kg (12,000 lb).

Discoveries and species

Triceratops was discovered by John Bell Hatcher in 1888. Its declaration as a legitimate dinosaur came when an intact skull was found. It was named by Othniel Charles Marsh in 1889. Some time earlier in 1887 near Denver, Colorado, however, he misidentified the Triceratops as a type of bison. The sturdy nature of the animal's skull has ensured that many examples have been preserved as fossils, allowing variations between species and individuals to be studied.

Known species of Triceratops include T. prorsus and T. horridus. Diceratops was formerly believed to be a species of Triceratops as well, but is currently recognized as a separate genus and species.

Triceratops species:

• T. horridus Marsh, 1889 (type species)
• T. prorsus Marsh, 1890

Nomina dubia:

• T. albertensis Sternberg, 1949
• T. alticornis Marsh, 1887 (originally 'Bison')
• T. eurycephalus Schlaikjer, 1935
• T. galeus Marsh, 1889
• T. ingens Lull, 1915
• T. maximus Brown, 1933
• T. sulcatus Marsh, 1890

Misassignments:

• T. brevicornis Hatcher, 1905 (=T. prorsus)
• T. calicornus Marsh, 1898 (=T. horridus)
• T. elatus Marsh, 1891 (=T. horridus)
• T. flabellatus Marsh, 1889 (=T. horridus)
• T. hatcheri Lull, 1907 (=Diceratops hatcheri)
• T. mortuarius Cope, 1874 (also nomen dubium; originally Polyonax; =Polyonax mortuarius)
• T. obtusus Marsh, 1898 (=T. horridus)
• T. serratus Marsh, 1890 (=T. horridus)
• T. sylvestris Cope, 1872 (nomen dubium; originally Agathaumas; =Agathaumas sylvestris)

Horns and frill

The distinctive skull of Triceratops had a single horn on the snout above the nostrils, and a pair of horns approximately 1 m (3 ft) long above the eyes. The rear of the skull bore a relatively short bony frill.

A number of purposes have been proposed for the frill:

• Defense against carnivores such as Tyrannosaurus rex
• Communication between herd members
• Battling rival Triceratops over status, resources, or territory
• Courtship display
• A status symbol which reflects (or determines) the individual's status in the herd
• Anchor points for the jaw muscles
• Increasing body area to regulate body temperature

Biology

Paleontologists deduce from the evidence of ichnites (fossil footprints) of dozens of individual animals, that Triceratops lived in herds, similar to those of modern-day buffalo. Its food was plants and shrubbery and its snout consisted of a sharp beak, which would have enabled it to break up and eat very tough vegetation. Behind the beak, Triceratops had a series of teeth arranged in a shearing mechanism. Triceratops possessed a sturdy build, with robust legs and five hoofed toes. Triceratops teeth are among the most abundant fossils in the Late Cretaceous of Western North America (65 mya), suggesting that it was the dominant herbivore of the time.

It is estimated that Triceratops was able to run at around 24 km/h (15 mph), since its short legs meant it could not take long strides.

In 2005, a BBC documentary, The Truth About Killer Dinosaurs, tested how Triceratops would defend itself against large predators like Tyrannosaurus rex. To see if Triceratops could charge other dinosaurs like a rhinoceros, an artificial Triceratops skull was made and propelled into simulated T. rex skin at 24 km/h (15 mph). The brow horns penetrated the skin, but the blunt nose horn and beak could not, and the front of the skull broke. The program therefore concluded that it would have been impossible for Triceratops to defend itself in this way - instead, it probably stood its ground when attacked by large predators, using its horns if the predator came close enough. One triceratops alone would probably not have been able to do too much against a T. rex. However, the whole herd, with their horns, may have some impact.

Depiction in popular media

• Many (if not most) dinosaur movies have included Triceratops. One Million Years B.C. (1966) features Triceratops in a memorable but anachronistic battle with Ceratosaurus. In Jurassic Park (1993), an immobilized Triceratops is depicted as having a mysterious illness; the role given to a Stegosaurus in the novel.
• A popular children's book is Oliver Butterworth's The Enormous Egg, where a friendly Triceratops hatches from an unusually large hen's egg.
• Triceramon, a Digimon, is based on Triceratops.
• Triceratops is the official state fossil of South Dakota, and the official state dinosaur of Wyoming.
• In Mighty Morphin Power Rangers, the Triceratops was Billy Cranston's power source. In Power Rangers: Dino Thunder, the Triceratops was Ethan James's zord.
• The Transformers characters of Slag, Triceradon and Guiledart each turn into a Triceratops.
• The 2005 bbc documentary The Truth About Killer Dinosaurs featured a Triceratops. It was put against a Tyrannosaurus in the first episode, with the Triceratops being the victor.