Of course, there were no people on the earth when dinosaurs were alive. So how do we know about dinosaurs and other animals of long ago?
Sometimes, when a dinosaur died, its body lay on the muddy ground. The soft parts rotted away, but mud covered the bones and kept them from rotting. Over millions of years, the bones and the mud turned into rock. This helped keep them whole. Over many more millions of years, sun and rain wore away the rock around it, leaving the rocky skeleton. These rocky bones and skeletons are called fossils.
Scientists look for fossils such as this and dig them out of the ground. By studying fossils, the scientists can tell what the animal looked like. They can tell what it ate by the shape of its teeth. Often, they can even tell how well the animal could see and hear and smell things.
Some creatures living in the world today look very much like some of the fossils of ancient animals. By studying these creatures, scientists can get an even better idea of life on the earth millions and millions of years ago.
Picture Credit : Google