Prehistoric creatures refer to animals that lived during the time before written history, primarily during the Paleozoic, Mesozoic, and Cenozoic eras. These creatures include well-known dinosaurs like the Tyrannosaurus rex and the Triceratops, as well as ancient marine life such as ammonites and ichthyosaurs. Fossils of these animals provide valuable insights into their physical characteristics and habitats. Many prehistoric creatures adapted to their environments in unique ways. For example, the woolly mammoth had thick fur to survive in cold climates, while the saber-toothed cat had long, sharp teeth for hunting. Understanding these creatures helps scientists learn about evolution and the Earth's history.