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Dinosaurs are very interesting animals . They are huge but there are also very small kinds. Some dinosaurs go on four legs but some run on two legs. Dinosaurs are also predators or vegetarians. Most of the dinosaurs had small brain especially the huge vegetarian Diplodocus. The dinosaurs resembled to the lizards. Dinosaurs were the biggest animals which lived on the Earth. However were the dinosaurs big and strong , they unfortunately died out. They are now extinct animals .

The first dinosaurs lived 230 million years ago. The last dinosaurs died out 65 million years ago. Scientists think that various dinosaurs evolved by millions of years from a lizard called Lagosuchus. Not all dinosaurs lived in the same time. When one sort died out, another sort overtook his place. The era of dinosaurs is divided to three periods. They are called trias, jura and chalk.

The trias period was long 30 million years. In this period lived the first dinosaurs like Herrerasaurus and Stauricosaurus.

The jura period was long 60 million years. In this period lived some famous dinosaurs like Stegosaurus and other vegetarian sauropods.
Stegosaurus had a double row of plates running down its back. Stegosaurus means roofed lizard ,because the bony plates on its back look like the top of a roof. It was as big as a large lorry, with back legs as tall as a long ladder. Despite its size, Stegosaurus had a brain the size of a walnut. It had very weak teeth and could only eat soft plants. When it was angry, the plates along its back may have gone a scary shade of red. Its only real weapons were four nasty spikes on the end of its tail.
Barosaurus was a big , but stupid dinosaur. He was a vegetarian and ate ferns and leaves from very tall trees. It was as long as three buses and its neck was as long as a lamppost. Barosaurus was too big to be eaten by predators. Barosaurus means heavy lizard.
Brachiosaurus had 78 tons , it was 27 metres long and 12 metres high. It was also a vegetarian.
Diplodocus was one of the longest of all dinosaurs- it had 29 metres. It used its long tail for balance and also as a weapon. Diplodocus moved around in large groups. It had to swallow stones to help grind up the tough plants in its tummy.
Compsognathus was no bigger than a hen.

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