You can learn a lot about dinosaurs by looking at their bones. Some dinosaurs were very small; others were huge. Some had sharp, pointy teeth for eating meat; most plant-eaters had flat, dull teeth. Some dinosaurs' hipbones pointed forward, while other dinosaurs' hipbones pointed backward. There were dinosaurs with bony armor on their backs and others with deadly horns on their heads. Today scientists have divided dinosaurs into separate orders according to their special characteristics. It's easy to see -- dinosaurs are different.