By the late Holocene, most archaeological sites in the central Rift Valley display a significant pastoralist occupation and are dominated by cattle and caprines, while others preserve an abundant wild grassland fauna with substantial numbers of cattle and caprines (Gifford, Isaac, and Nelson 1980).
2008, Charles R. Peters, et al., 3: Paleoecology of the Serengeti-Mara Ecosystem, A. R. E. Sinclair, Craig Packer, Simon A. R. Mduma, John M. Fryxell (editors, Serengeti III: Human Impacts on Ecosystem Dynamics, page 77