Saurichians

Saurichians are divided into three main groups:

• Prosauropods
• Sauropods
• Theropods.

Sauropods were giants like the 'Apatosaurus' and the 'brontosaurus' that typically had long necks and tails and small heads.

Theropods, on the other hand, mostly had large heads and were the only meat-eating dinosaurs. (Most dinosaurs were plant-eaters).

The 'T-Rex', 'Allosaurus' and 'Velociraptor' (which also made an appearance in Jurassic Park) were all Theropods. And you’ll notice, after looking at pictures of them that they all walked on their hind legs, like birds do.