The megalodon, “big tooth” in Greek, is an extinct megatoothed shark that existed in prehistoric times, from the Oligocene to Pleistocene epochs, approximately 25 to 1.5 million years ago. Paleontological research indicates that Carcharodon megalodon is among the largest and most powerful macro-predatory fishes in vertebrate history, approaching a length of around 20.3 meters (67 ft).