This is the study of prehistoric life based on fossil evidence. Fossils provide evidence about life on Earth millions, or even billions, of years ago. They can be preserved remains of living things, such as bones or teeth. Fossils also can be impressions left in stone, like animal tracks or the shape of a leaf.
Scientists who study fossils are called paleontologists (Pay-lee-en-TOL-oh-jists). Paleontologists compare fossils to find clues about early organisms and how they lived. Fossils can show how organisms evolved over very long periods of time. They also show how living things today relate to those from millions of years ago. Some fossils even give clues about how ancient organisms went about their daily lives. For example, fossil footprints suggest some dinosaurs lived in groups.