Large predators are increasingly appearing in unexpected places — alligators in saltwater marshes, killer whales in rivers, and mountain lions far away from the closest mountain. Experts hypothesize that as successful conservation efforts increase the local populations of these predators, they are moving beyond their usual habitats in search of food. However, Brian Silliman, professor of marine conservation biology at Duke University, has a different theory. He believes the animals are recolonizing habitats they lived and hunted in for centuries — before human activity pushed them to the brink of extinction, and long before researchers began studying them.