Prehistoric animals are those that lived before recorded history. The most well-known of these is the DINOSAUR, which is an 8-letter word. Another prehistoric animal is the Eohippus, also an 8-letter word, which was a small horse-like creature that lived during the Eocene epoch. The MAMMOTH, a 7-letter word, was a large elephant-like creature that lived during the Pleistocene epoch. The Stegosaur, a 9-letter word, was a large herbivorous DINOSAUR with plates along its back and a tail with spikes. The DIPLODOCUS, a 10-letter word, was a large long-necked DINOSAUR that lived during the Jurassic period. Finally, the Pterosaur, a 9-letter word, was a flying reptile that lived during the Mesozoic era.