When Did the Dinosaurs Live?
Dinosaurs lived throughout the Mesozoic Era, which began 245 million years ago and lasted for 180 million years. It is sometimes called the Age of the Reptiles. The era is divided into three periods.
245 to 208 million years ago
Dinosaurs that lived during the Triassic period include:
Coelophysis (“hollow form”; found in the U.S.): a 9-foot long carnivore that was quick on its feet
Desmatosuchus (“link crocodile”; found in Texas): a reptile that looked like a crocodile and had sharp spikes on its back
Eoraptor (“dawn thief”; found in Argentina): the earliest-known dinosaur; walked on two feet
Ichthyosaurs (“fish lizards”; found in England, Germany, Greenland and Canada): this order of marine reptiles dominated the ocean during the Triassic period
Iguanadon (“iguana teeth”; found in North America, Europe and Asia): the first dinosaur to be discovered; its bones and teeth are different from any other known reptile
Plateosaurus (“flat lizard”; found in dozens of sites in Europe): an herbivore that had five-fingered hands with a clawed thumb
Proganochelys (found in Germany and Thailand): the earliest-known turtle
208 to 146 million years ago
Dinosaurs that lived during the Juraissic period include:
Allosaurus (“different lizard”; found in western North America): the biggest meat-eater of the period, measuring about 40 feet long
Apatosaurus formerly called Brontosaurus (“deceptive lizard”; found in the western U.S.): the dinosaur measured between 70 and 90 feet, but its head was only about 2 feet long
Archaeopteryx (“ancient wing”; found in Germany): one of the earliest-known birds, this creature shared many characteristics with dinosaurs
Compsognathus (“pretty jaw”; found in Germany, France and Portugal): the smallest-known dinosaur was about the same size as a chicken
Diplodocus (“double-beamed”; found in western North America): At 90 feet long, this was one of the longest land animals
Mamenchisaurus (“Mamenchin lizard”; found in China): this dinosaur’s neck measured an amazing 46 feet long
Stegosaurus (“plated lizard”; found in U.S., Europe, India, China and Africa): a three-ton giant with the brain the size of a walnut
146 to 65 million years ago
Dinosaurs that lived during the Cretaceous period include:
Ankylosaurus (“bent/crooked lizard”; found it Montana and Alberta, Canada): the most heavily armed dinosaur, with bony plates, studs and spikes lining its entire back
Giganotosaurus carolinii: (“giant southern lizard”; found in Argentina): measuring about 45 feet long and weighing about 8 tons, it holds the record as the largest carnivore
Hadrosaurus (“bulky lizard”; found in New Jersey): this herbivore had a toothless bill but many cheek teeth
Megaraptor (“huge robber”; found in Argentina): a fast runner with a sickle-shaped claw on each foot
Orinthomimus (“bird mimic”; found in China): at an estimated 40 to 50 miles per hour, this was the fastest dinosaur
Seismosaurus (“seismic lizard”; found in New Mexico): considered the largest dinosaur, it measured 120 feet long and stood about 18 feet high
Triceratops (“three-horned face”; found in Canada and western U.S.): this quadraped (four-footed) dinosaur walked on its four stumpy legs and used the three horns on its head for protection.
Troodon (“wounding tooth”; found in North America and Asia): largest brain-to-body ration of all known dinosaurs; believed to be as intelligent as modern birds
Tyrannosaurus rex (“tyrant lizard”; found in North America and Asia): T. rex, king of the dinosaurs, dominated the period.
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