The Paleolithic (American spelling; British spelling: Palaeolithic; pronunciation: ) Age, Era or Period is a prehistoric period of human history distinguished by the development of the most primitive stone tools discovered (Grahame Clark's Modes I and II), and covers roughly 95% of human technological prehistory. It extends from the earliest known use of stone tools, probably by hominins such as australopithecines, 2.6 million years ago, to the end of the Pleistocene around 10,000 BP.