The dinosaurs appear
Small, fast reptiles that will rule for 160 million years
See it on the timeline →In depth
Eoraptor and Herrerasaurus from the Ischigualasto Formation in Argentina are among the oldest known. The decisive trait is a hip in which the femur drops straight into an open socket, giving an upright gait and far better endurance than the sprawling stance of other reptiles. Dinosaurs dominated from the late Triassic to the end of the Cretaceous. Birds are not merely related to them — they *are* dinosaurs, the one branch that survived.
For children
The first dinosaurs were not giants — they were dog-sized and ran on two legs. But they had a clever hip and light bones that made them fast. Within a few million years they had taken over the world.
Connects to
Part of Terra Saga — the story of Earth on a timeline. terrasaga.org