The word dinosaur comes from the Greek language and means ‘terrible lizard’. The word was coined by English paleontologist Richard Owen in 1842 and was meant to refer to Dinosaurs impressive size rather than their scary appearance. Dinosaurs ruled the Earth for over 160 million years, from the Triassic period around 230 million years ago through the Jurassic period and until the end of the Cretaceous period around 65 million years ago. The time period from 250 million years ago until around 65 million years ago is known as the Mesozoic Era. It is often referred to as the Age of the Dinosaurs because most dinosaurs developed and became extinct during this time. It is believed that dinosaurs lived on Earth until around 65 million years ago when a mass extinction occurred. Scientists believe that the event leading to the extinction may have been a massive asteroid impact or huge volcanic activity. Events such as these could have blocked out sunlight and significantly changed the Earth’s ecology. The first dinosaur to be formally named was the Megalosaurus, back in 1824. A person who studies dinosaurs is known as a paleontologist. Rather than being carnivores (meat eaters), the largest dinosaurs such as the Brachiosaurus and Apatosaurus were actually herbivores (plant eaters).