They're not exactly fish, and they're certainly not snakes that live in water. What they are - if you can get over the slithery, darting weirdness of eels - is fascinating: truly ever-changing, versatile and resilient. To discuss the remarkable characteristics of eels, Nam Kiwanuka welcomes Patrik Svensson, journalist and author of "The Book of Eels: Our Enduring Fascination with the Most Mysterious Creature in the Natural World;" and Steven Cooke, professor and Canada Research Chair of Environmental Science and Biology at Carleton University.