Of course, no human being has ever seen a living dinosaur. The dinosaurs had been extinct for about 63 million years before humans appeared on Earth.
If no one has ever seen a dinosaur how do we know what they look like? Well, scientists have found their fossilized bones, sometimes they have even found complete skeletons.
By studying dinosaur bones, scientists have been able to reconstruct what they looked like, how they moved, even what they ate. Most of what we think we know about dinosaurs is the result of educated guesses based on comparing the dinosaur skeletons with modern animals.
Dinosaurs were created as an identifiable group of ancient animals by British scientist Richard Owen who, in 1842, coined the name Dinosauria meaning "terrible lizards." At the time there were three recently discovered fossil creatures to be included in the newly created group of ancient animals. These were Iguanadon, Hylaeosaurus and Megalosaurus.
Scientists today classify dinosaurs as reptiles although they were somewhat different from such modern reptiles as snakes and lizards. The closest living (living today) relatives of the dinosaurs are thought to be birds. Where have dinosaur bones been found?
The first known discovery of dinosaur bones happened in 1786 when an enormous skull with jaws a meter long was found in a chalk quarry in the Netherlands.
Then, about 1810, eleven-year-old Mary Anning unearthed some unusual fossil bones in the 200-million-year-old limestone cliffs of Lyme Regis in Dorset, England. During the next twenty years or so the Anning family collected the fossils -- remains of ichthyosaurs ("fish-lizards") and pleisosaurs ("near-lizards") -- and sold them to tourists and to scientists from Cambridge and Oxford.
In 1825 a quarry near Cuckold, Sussex revealed some mysterious fossilized bones that were reconstructed by the local doctor and naturalist Gideon Mantell as Iguanadon.
In America, strange fossil footprints discovered in Massachussetts in 1802 were wrongly identified in 1836 as the three-toed prints of a huge bird. Fossil hunting in the U.S. took off in the 1870's. In the 1880's Othneil Marsh of Yale was the first to reconstruct Brontosaurus ("thunder lizard").
In 1907 the fossilized remains of an immense Brachiosaurus was found in East Africa. The first dinosaur nests and fossilized eggs were found in 1922 in Mongolia.
Evidence of dinosaurs has now been found on every continent of the world.