The history of Ohio includes many thousands of years of human activity. What is now Ohio was probably first settled by Paleo-Indian people, who lived in the area as early as 13,000 B.C. A fossil dated between 11,727 and 11,424 B.C. indicates they hunted large animals, including Jefferson's ground sloth, using stone tools. Later ancestors of Native Americans were known as the Archaic peoples. Sophisticated successive cultures of precolonial peoples indigenous peoples, such as the Adena, Hopewell and Mississippian, built monumental earthworks as part of their religious and political expression: mounds and walled enclosures, some of which have survived to the present.