What Is and Is Not a Dinosaur?
by AMNH on
A key evolutionary innovation of dinosaurs is that they walk with a fully erect posture, holding their hind legs vertically under their hips. What else makes a dinosaur a dinosaur? Learn how scientists define this group of reptiles in the first video from the AMNH.tv series "Dinosaurs Explained."
Visit AMNH.tv for more from the "Dinosaurs Explained" series.