For tens of thousands of years, human communities in West Africa grappled with some of the most varied and challenging environments in the world. The members of these communities evolved strategies for living on the arid grasslands of the Saharan edge, in the savanna woodlands to the south, and even down in the wet green rainforests north of the Gulf of Guinea. Like the successful Stone Age pioneers elsewhere in the African and Eurasian tropics, early West Africans drew upon a shared cultural tradition of tool-making to fashion clothing, shelter, storage containers and weapons. They used fire to shape their immediate domestic and natural environments. They cooked meat, fish and plants, transforming the yields from their hunting, fishing and gathering. In order to improve their hunting prospects, they burned patches in the grasslands and woodlands to draw wild game to the resulting fresh plant growth. In the rainforests, where lightning and natural tree fall had already tom holes in the green canopies, they charred out biologically productive edge environments, or ecotones, that likewise enhanced their opportunities to harvest wild game.

The ecological zones in which early West African pioneers struggled can be depicted on a map as long and narrow bands that extend from east to west across the region. These ecological bands are characterized by distinctively different annual rainfall profiles as well as different plant and animal populations. Over a mere 2000 kilometers, a succession of highly diverse ecological zones begins at the southern edge of the Sahara, known as the sahel, where only plants and animals that have adapted to very arid conditions are able to survive. Below the sahel begins the vast and open grasslands known as the savanna, and then, at the southern edge of these grasslands, begins an ecological zone with an even denser distribution of trees, known as the woodlands. These open forests in turn merge into the nearly full humidity of the tropical rainforests and lagoons along the Gulf of Guinea.

For the countless generations of early pioneers, travel within and across one or more of these ecological zones was a common experience, building up an ecological knowledge of plants, animals, insects, water supplies and mineral resources.