Even though we generally think of footprints as ephemeral, in the right conditions, footprints can be preserved for an extraordinarily long time, even millions of years. Preserved footprints give paleontologists details that fossils alone can't. By looking at the sediments or rocks where the footprints are located, researchers can get an idea of what kind of environment the dinosaurs were living in. By looking at their size and depth, they can get a better idea of how big or small the dinosaur was, even without any remaining flesh. Looking at how different tracks of footprints overlaps can even tell scientists how different species of dinosaurs interacted with each other. And looking at the spacing between footprints, scientists can figure out how fast the dinosaurs were going when they walked the Earth those many years ago. Looking at how different tracks of footprints overlaps can even tell scientists how different species of dinosaurs interacted.