Prehistoric creatures shed their shells much like some of today's marine creatures do. Thus, shielded parts of animals have been found fossilized also. Bones are the main means of learning about animals. By mapping out how bones are lying in the ground, scientists find out how the specimen was deposited and perhaps how it got there. Studying the bones helps scientists to identify the type of animal, discover new species of dinosaurs, and how they relate to present day creatures such as turtles, crocodiles, lizards, and other amphibians.
Trace fossils record the movements and behaviors of the dinosaurs.
Trackways were usually made in mud or fine sand, and have been found at over 1500 sites, including quarries, coal mines, riverbeds, deserts, and mountains. These fossils are in abundance because dinosaurs made many tracks with their constant movement, and because tracks fossilize so well. Fossil footprints can provide paleontologists with information about speed and length of the stride of the dinosaur, whether they walked on two or four legs, and the bone structure of the foot. Things such as stalking behavior, and existence of dinosaur herds and stampedes can also be gathered from trackways. Unfortunately, linking a set of tracks with a particular species of dinosaur can prove to be quite difficult.