Yellowstone National Park is the world’s first national park, founded in 1872. Large predators were decimated in the park, and wolves eradicated, but wolves were returned in 1996 leading to a ‘trophic cascade’ effect which has been studied in great depth. This research examines whether the changes seen post wolf reintroduction in 1996 are restoring Yellowstone to its original state, and whether historical sources can be used for biological research.