Over the last several weeks, I've been reading The Civilizations of Africa: A History to 1800 by Christopher Ehret. This book was published in 2002 and is based upon Ehret's work as a linguist studying African languages. The Amazon link for this book can be found here.
The book describes the placement and economy of early Afroasiatic, Nilo-Saharan, Niger-Congo, Khoisan and BaTwa communities starting at approximately 21,000 ybp. He describes how each of these communities employed and developed food acquisition methods in response to changes in their local climates.
Relevant to the discussion of domestication on the Nile is Ehret's description of two distinct cultures: The proto-Afroasiatic culture originating along the Red Sea Hills and northern Ethiopian highlands and the proto-Nilo-Saharan culture of the middle Nile. Map 4 of the book illustrates the proposed locations for these proto cultures:
post). Early Nilo-Saharan peoples are believed to have lived at the confluence of the White and Blue Nile (post).
These groups gradually expanded outwards from their homelands, especially after 10500 bp during the phase of the green Sahara. Ehret refers to this phase as the Holocene Climatic Optimum. (On this blog, it has previously been referred to as the Great Wet Phase of the Sahara.) Ehret points out that during these expansions, the Afroasiatic and Nilo-Saharan cultures came into contact with each other. There is linguistic evidence of cultural exchange, including the exchange of knowledge about plant and livestock cultivation. The forms of exchange are quite detailed and I would be doing the author a disservice to copy his recently published work directly on this blog.
Ehret's book is available on Amazon for a modest price. I have read the first four chapters and I believe the book deserves at least four stars, so don't be fooled by the review of one disgruntled reader. In addition to the in depth discussion on Afroasiatic and Nilo-Saharan cultures, there is the remarkable early history of Niger-Congo, Khoisan and BaTwa peoples. African domestication of various crops such as cotton, sorghum, yams, millet, black-eyed peas, palm oil and African groundnut are explored. The book is easy to read and does not require any specialist knowledge of African archaeology or linguistics.
Regarding the recent discussion on this blog, Ehret's linguistic deductions do support the assertion that cattle were domesticated independently by the Nilo-Saharans at about 10,000 bp. He also suggests that Afroasiatic speakers of the Red Sea hills may have engaged in a form of "protection of wild cows". As of the 2002 publication, Ehret stated that the exchange of knowledge regarding cattle herding between Nilo-Saharans and Afroasiatic speakers of the Red Sea hills is as yet poorly understood.