Explore an A-to-Z list of over 700 dinosaurs that lived during the Triassic, Jurassic, and Cretaceous periods. How many dinosaur names do you know? Learn everything about dinosaurs , from their definition and evolution to their extinction and types. Explore lists of dinosaurs by period, see pictures and info, and discover how dinosaurs are related to birds. Quick facts about dinosaurs for kids and grown-ups! Find out what dinosaurs ate, how they may have behaved, what they may have looked like, and more. Dinosaurs are a diverse group of reptiles [note 1] of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is a subject of active research.
