The continent of South America was isolated for millions of years during the Cenozoic Period, which had a significant impact on its wildlife. This isolation helped foster species that were not found anywhere else on Earth. Approximately 3 million years ago, the Great American Biotic Interchange occurred due to the Isthmus of Panama, which allowed for the mixing of North and South American faunas. The mixing of faunas created new opportunities for expansion, competition, and replacement of species. South American wildlife in the Pleistocene varied greatly; an example is the giant ground sloth, "Megatherium". The continent also had quite a few grazers and mixed feeders such as the camel-like litoptern "Macrauchenia", "Cuvieronius", "Doedicurus", "Glyptodon", "Hippidion" and "Toxodon". There were also "Stegomastodons", found as far south as Patagonia. The main predators of the region were "Arctotherium" and "Smilodon".