Terrifying Lizards: Rulers of Their Day

4 Terrifying Lizards: Rulers of Their Day They've been extinct for more than 65 million years. They left no pictures or libraries filled with books. Yet, they live on in the imaginations of people of every age and nationality. Mention the word “ dinosaur" to anyone and you're bound to have something to talk about. We have known about these strange creatures for less than 200 years. Their fossil record was first discovered in 1818. The word “ dinosaur" was coined in 1842 by a scientist who put two Greek words together-deinos, which means “ frightening thing" , and sauros which means “ lizard" . They were large reptiles that roamed the earth in prehistoric times. Of all the creatures living in that era, dinosaurs were the most numerous. They were feared by all the other life forms. And for almost 200 million years, before their quick and mysterious disappearance from the earth, dinosaurs ruled this planet.

What we know about dinosaurs comes only through the fossil record they left behind. We can get an idea of how they looked by reconstructing their skeletons using fossilized bones and teeth. We have a pretty good picture of their size and structure, but not much else is known for certain. We do know that they lived on land and walked erectly. They must have been impressive as they towered high above the other creatures of their time. Some walked on two legs. Others preferred four legs. Some were fast and others were quite slow. Remember, we are working only with the bones they left behind when we study dinosaurs. This limits us in what we can really know about them. For example, what colour were they? Nobody knows. Did they roar like lions, or were their voices sweet and musical like birds? Again, how can we know? The fossil record does not speak. Keep in mind that what we don't know about dinosaurs is far greater than what we do know about them. As with a lot of research about prehistoric times, scientists often have to read between the lines.