The earliest dinosaurs resembled two-legged, short-headed crocodiles, but later dinosaurs were oddly reminiscent of giant mammals and birds.

Some dinosaurs spent time in the water, but no dinosaur could swim very well.

It's easy to tell a dinosaur skeleton from that of a modern reptile because dinosaur skeletons have a strong joint between the backbone and hips.

Some dinosaurs had feathers.

Small, two-legged dinosaurs could turn rapidly by swinging their tail abruptly in a direction opposite to where they wished to turn.

Source: MSN Encarta