Megalodon (full name Otodus megalodon) means "Big Tooth" - a suitable moniker for what may be the biggest shark to have ever lived. This absolute unit grew to be an average of 15 meters in length. Its razor-sharp teeth were as large as a human's hand, reaching an average diagonal length of 18 centimeters. Because sharks' skeletons are mostly made out of cartilage, the only fossils paleontologists have of Megalodon are teeth, vertebrae, and coprolites. This makes it difficult to reconstruct what it would have looked like in life, but we can assume that it looked like a huge basking shark or thick great white. Megalodon prowled the oceans of the Neogene Period in subtropical and temperate waters. As juveniles, they stayed in shallow coastal environments, but as adults they preferred deeper water offshore. Their prey of choice were smaller cetaceans, and several whale bones have been discovered with massive cuts from Megalodon teeth. They competed with predatory whales like Livyatan for prey, which is one factor that lead to their extinction. Although popular Shark Week documentaries claim that this giant species might still exist, it is impossible that it has survived. It was not equipped to dine on the larger whales that evolved, it could not compete with killer whales, and could not take the colder climate.