The Prehistory of West Africa spans from the earliest human presence in the region until the emergence of the Iron Age in West Africa. Acheulean tool-using archaic humans may have dwelled throughout West Africa since at least between 780,000 BP and 126,000 BP (Middle Pleistocene). During the Pleistocene, Middle Stone Age peoples (e.g., Iwo Eleru people, possibly Aterians), who dwelled throughout West Africa between MIS 4 and MIS 2, were gradually replaced by incoming Late Stone Age peoples, who migrated into West Africa as an increase in humid conditions resulted in the subsequent expansion of the West African forest. West African hunter-gatherers occupied western Central Africa (e.g., Shum Laka) earlier than 32,000 BP, dwelled throughout coastal West Africa by 12,000 BP, and migrated nort