Dinosaurs were a superorder of reptiles that first appeared approximately 230 million years ago. A few lines of primitive dinosaurs diversified rapidly after the Triassic; the reign of dinosaurs encompassed the ensuing Jurassic and Cretaceous periods. At the end of the Cretaceous, 65 million years ago, nearly all species of dinosaur became extinct (the Cretaceous-Tertiary extinction event), except for the line that had already led to the first birds. There is now sufficient evidence to demonstrate that the birds are the descendants of theropod dinosaurs. Warm-blooded vertebrates without fur or feathers did not survive what appears to be a very cold period following a meteor strike on the Earth, thus ending the non-avian dinosaurs species which formerly were thought to be all the dinosaur species.

The formal name Dinosauria was first proposed by the English scientist Richard Owen in 1842. The term is a combination of the Greek words deinos ("terrible" or "fearfully great" or "formidable") and sauros ("lizard" or "reptile").Dinosaurs are extremely varied; some herbivorous, others carnivores; some bipedal, others quadrupedal.Dinosaurs have long captured the public mind, and children are especially fascinated with them.

The most famous dinosaurs are Tyrannosaurus rex, Triceratops, Stegosaurus, and Diplodocus amongst others.

A Triceratops named Crinkles was a main dinosaur character in the Smurfs cartoon show. There were also other dinosaurs in the series.