|- |(unranked)||Coronosauria T. prorsus
T. horridus

Triceratops ( "three-horned face") is a ceratopsid herbivorous dinosaur genus from the Latest Cretaceous period of North America. It was about 9 m (30 ft) long, 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. Two years earlier, 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.

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 the herd members.
• Battling another Triceratops over female or territory.
• Courting females.
• 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 temperature (see also: thermoregulation).

Biology

Owing to evidence from fossil trackways showing the footprints of dozens of individuals, paleontologists believe 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 a series of teeth arranged in a shearing mechanism. Triceratops was approximately 9 m (30 ft) long and strongly built. It had robust legs and and hoofed toes.

Trivia

Countless 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 Stegosaurus in the novel.

In the United States, Triceratops is the official state fossil of South Dakota, and the official state dinosaur of Wyoming.

External links

• Triceratops (short summary and good color illustration)
• Triceratops For Kids (a fact sheet about the Triceratops with activities for kids)
• Smithsonian Exhibit