The ‘overgrown lizard’ is that most frightening of extinct animals. Tyrannosaurus Rex. There were some dinosaurs even larger than Tyrannosaurus, but they were harmless, placid, grazing animals. Tyrannosaurus was a carnivore a meat eater and its breakfast was probably another, less powerful dinosaur.
Thanks of fossil remains, we have a good idea of what this monster looked like. It stood nearly 7m (23ft) high to the top of its horny head, and its great jaws were lined with curved teeth up to 15 cm (6in) in length. It walked upright (as some lizards do now) and probably moved quite fast, rocking from side to side as it pounded along on its claw like feet. The tail helped it to keep its balance.