What are dinosaurs?
Dinosaurs are a group of reptiles that dominated the land for over 140
million years. They are defined by their anatomy, with straight backs
perpendicular to their bodies. Their legs were also positioned under
their bodies (rather than on either side like lizards), which better
supported their weight.
Unlike what many movies portray, not all extinct reptiles from that time
period are dinosaurs. Non-dinosaur reptiles include pterosaurs (extinct
flying reptiles) and marine reptiles.
Main characteristics of dinosaurs include:
- They had an upright stance, with legs perpendicular to their body.
- They laid eggs.
- They lived on land (with a few exceptions).
- Their skull had a hole between the eye socket and nostril.
- Dinosaurs also had two holes behind the eye socket. Large, strong jaw muscles went through the holes to attach directly to the top of the skull.
