Before the 1800’s no one even knew that dinosaurs even existed. When people found a bone or tooth, they had no idea what it was. Around 1818, an English scholar, William Buckland, obtained a large lower jaw that contained a number of sharp teeth. After studying the jaw, he decided that it was unlike any other fossil ever found. He gave it the name Megalosarus, meaning great lizard.

Around this time an English naturalist, Mary Ann Mantall, found a large tooth partly buried in a rock. She and her husband, Gideon, decided that the tooth looked like one of an iguana and thus named it Iguanodon.

The Magalosarus and the Iguanodon were the first dinosaurs to actually have a name.

During the late 1800’s and early 1900’s, large deposits of dinosaur remains were discovered in North America, Europe, Asia, and Africa. During th

It has been determined that the dinosaurs lived during what is now called the Mesozoic Era. This era is divided into three periods: Triassic, Jurassic, and Cretaceous. The Triassic period lasted from approximately 248-213 million years ago, the Jurassic period lasted from about 213-145 million years ago, and the Cretaceous period from about 145-65 million years ago.

It is not certain why the dinosaurs died out. Scientist have developed many theories. One major theory is that of a gradual change in climate toward the end of the Cretaceous Era causing shallow seas to dry up and the climate to become more varied everywhere around the globe. Winter became too cold and summers became too hot for dinosaurs to survive. Dinosaurs were too big to hibernate in caves and they had no fur or feathers to protect them against the cold. They probably had difficulty cooling off in the summer thus, death and extinction came as a result of the changes in climate.

We can only guess how long dinosaurs lived, but scientist can estimate the time it took for them to grow to full adult size. If they were endothermic, it probably took thirty years to reach average adult weight and size.

Traditionally dinosaurs were considered endothermic, or warm blooded. They point out that many dinosaurs were more active and therefore maintained a more constant body temperature. Other dinosaur features, such as the internal bone structure, and the chemistry of the bone, also suggest that some dinosaurs were warm blooded.

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