Rob Dunn is the author of The Wild Life of Our Bodies, the story of our changing relationship with predators, parasites, mutualists, commensals, and all the rest. He is a science writer  and scientist  at North Carolina State University, where he studies the stories of the species that have lived alongside humans as we have spread around the world, be they bacteria in your belly button ants in your backyard  or cave crickets in your basement.