WHAT'S INSIDE: DINOSAURS
- About Dinosaurs
- Early Triassic & Jurassic Dinosaurs
- Middle & Late Jurassic Dinosaurs
- Early Cretaceous Dinosaurs
- Late Cretaceous Dinosaurs
Tenontosaurus was a medium-size ornithopod dinosaur from Montana and Wyoming. Skeletons range in size from very small juveniles to almost 22-foot-long adults. Learn more about how this dinosaur lived and what it ate.
About 60 million years ago, something happened to wipe dinosaurs off the face of the Earth. These creatures dominated the landscape far longer than humans have been around, but many mysteries remain about their appearance, physiology and eventual extinction. So which of today's animals evolved from dinosaurs?