Eels have fascinated humans for thousands of years, even captivating big thinkers like Aristotle and Freud. Despite having been around for some 200 million years, eels are still rather mysterious creatures. For example, scientists still aren’t sure exactly how they spawn.But those unanswered questions haven’t stopped humans from wanting to eat them. So much so that they’re now endangered in some areas—and a lucrative criminal enterprise has risen up to poach baby eels from the wild.Guest host Rachel Feltman talks with Ellen Ruppel Shell, author of Slippery Beast: A True Crime History, with Eels about her journey into the wild world of eels.Read an excerpt of Slippery Beast: A True Crime History, with Eels. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.