Dinosaurs were a fascinating group of reptiles that dominated Earth for over 160 million years during the Mesozoic Era. Unlike modern reptiles, they lived exclusively on land and had unique body structures that made them incredibly successful. They ranged from tiny chicken-sized creatures to massive giants longer than school buses.
Dinosaurs are classified into two major groups based on their hip structure. Saurischia, or lizard-hipped dinosaurs, include the giant long-necked sauropods and the meat-eating theropods like T. rex. Ornithischia, or bird-hipped dinosaurs, were all plant-eaters and included armored dinosaurs, horned dinosaurs like Triceratops, and duck-billed dinosaurs.
Let's look at some famous dinosaurs. Tyrannosaurus rex was one of the largest land predators ever, with massive jaws filled with sharp teeth but surprisingly tiny arms. Stegosaurus had distinctive plates along its back and dangerous spikes on its tail for defense. Brachiosaurus was a gentle giant with an extremely long neck that allowed it to reach high tree branches that other dinosaurs couldn't access.