Learn
The age of dinosaurs, period by period
The Mesozoic Era ran from 252 to 66 million years ago and splits into three periods. Each page below explains the world of that period in plain language, then lists the best-documented dinosaurs from it.
Triassic251.9–201.4 MaThe world recovers, and the first dinosaurs appearJurassic201.4–145 MaGiants, and the first birdsCretaceous145–66 MaFlowers, horns, tyrants — and a sudden ending
Want the stages inside each period? Open the full timeline.