Cryptozoologists study cryptids: creatures whose existence has yet to be (or cannot entirely be) proven. Bigfoot, Nessie the Loch Ness Monster (yes, she has a name!), the Jersey Devil, El Chupacabra, Mothman, and werewolves are just a few of the many creatures that are studied in the world of cryptozoology. But, did you know that some real species we know about today were once considered cryptids?