5. Saltwater Crocodiles
Given the option to swim through a tank of crocs or sharks, most would choose the crocs, assuming they could out swim a croc. That would prove a fatal mistake. Sharks are fast, but crocodiles are more aggressive. They’re fast too, seven times the fastest human. The only predator for crocodiles are humans, which might be why they like to drown us when given the chance. An adult crocodile can live as long as a human and grow 23 feet long.