Andesaurus (/ˌændəˈsɔːrəs/ AN-də-SOR-əs; "Andes lizard") is a genus of basal titanosaurian sauropod dinosaur which existed during the middle of the Cretaceous Period in South America. Like most sauropods, it would have had a small head on the end of a long neck and an equally long tail. Andesaurus was a very large animal, as were many others of its relatives, which included the largest animals ever to walk the Earth.