Indigenous Hunter-gatherers Research Articles

Early Pastoralists in East Africa: Ecological and Social Dimensions

This article discusses the development of economies based on nonindigenous domestic cattle, sheep, goats, and donkeys in eastern Africa from the Lake Turkana basin south. It specifically addresses a previously noted delay of over a millennium in development of pastoral economies in the region. It argues that this lag could have been caused by novel epizootiological challenges encountered by pastoralists who had thrived in the Lake Turkana basin during the 5th millennium B.P. as they moved south into the Central Rift of Kenya. It reads the archaeofaunas, lithics, and ceramics in early “Neolithic” sites in Kenya and Tanzania as responses by immigrating pastoral groups and indigenous hunter–gatherers to an exceptionally dynamic environment, in which both climatic and veterinary factors made intergroup social alliances and exchange crucial.

Travelling Wave Solutions for the Spread of Farmers into a Region Occupied by Hunter–Gatherers

The geographical spread of an initially localized population of farmers into a region occupied by hunter–gatherers is modelled as a reaction–diffusion process in an infinite linear habitat. Hunter–gatherers who come in contact with farmers are converted at ratee. Growth of initial farmers, converted farmers, and hunter–gatherers is logistic with intrinsic ratesrf,rc, andrh. The carrying capacities of all farmers (i.e., initial and converted farmers combined) and hunter–gatherers areKandL. Individuals migrate at random, where the diffusion constant,D, is the same for all three groups. Under the above assumptions, we deduce the conditions under which wavefronts of initial or converted farmers are generated. Numerical work suggests that a travelling wave solution of constant shape always exists, comprising an advancing wavefront of all farmers and a retreating wavefront of hunter–gatherers. Linear analysis in phase space suggests that the speed is given by 2(Drf)1/2or 2[D(rc+eL)]1/2, whichever is greater. The composition of the expanding distribution of all farmers appears to depend on the relative magnitude ofrfversusrc+eLand ofeKversusrh. A wavefront of initial farmers is not generated ifrf<rc+eL. In this case, the initial farmers disappear completely ifeK<rh, whereas they spread mainly by diffusion behind the wavefront of converted farmers ifeK>rh. On the other hand, a wavefront of initial farmers is generated ifrf>rc+eL. In this case, the waveform is peaked with leading and trailing edges that converge to 0 ifeK<rh, while it is flat behind the wavefront ifeK>rhso that there is substantial displacement of the indigenous hunter–gatherers by the initial farmers.