Yellowstone National Park is home to hundreds of different species. While you are visiting, keep an eye out for all the different types of mammals, birds, fish, reptiles, and amphibians. The park has a long history of Native Americans, expeditions, and more recently, tourists. Ulysses S. Grant signed The Act of Dedication in 1872 making Yellowstone a National Park. Yellowstone is also known for its supervolcano which erupted around 630,000 years ago.