What Eurasia sent back stayed on Africa's edges

Traffic ran into Africa as well. Sheep and goats came south out of the Levant to northeastern Africa as early as the seventh millennium BCE, along with more cattle, and those two animals did eventually spread across most of the continent. The crops did much less. By the seventh and sixth millennia, barley and early wheats were growing along the Mediterranean fringe, where winter rain suited them, and in irrigated pockets of Egypt such as the Fayum. Sometime before the Sahara finished drying, probably in the fourth millennium, wheat, barley and chickpeas passed southeast into the highlands of Eritrea and northern Ethiopia, where cool-season rains gave them conditions close to Mediterranean ones. That is the whole list, and it stops at the coast, the Nile corridor and the highlands. Eurasian crops never reworked the farming of the African interior the way African crops reworked farming in South Asia. The exchange was real and the balance sat on Africa's side.

The Levisa rock shelter in Cuba holds a Lithic age deposit dated to 4190 BCE. It is among the earliest confirmed human occupations anywhere in the Caribbean islands. The people who left it worked stone, took what they needed from the rivers and the high ground behind them, and moved with the seasons rather than settling in one place. They were foragers, and the way they lived has to be kept separate from the Taino societies that European ships met almost six thousand years later. Those were farmers with villages, chiefs and ball courts, and they came out of a different tradition. This matters for how the region gets narrated. A Caribbean history that opens in 1492 treats the islands as empty until Europe arrives. A rock shelter in Cuba dated to 4190 BCE says the islands had been occupied for something like six thousand years by then, which makes the usual starting point a decision somebody took.

In the matrilineal societies spread right across Africa's southern savanna belt, a young man who wanted to marry applied to the mother of the woman and to her mother's female relatives, acting as a group. Their consent was the one that counted, ahead of her father's and ahead of her mother's brother's. To win it he performed bride service, working for months and sometimes for several years under their direction. After he was accepted and married he was still required to show marked deference to his mother in law for the rest of her life. Marriage is the central economic and reproductive transaction any society makes, and here the women of the lineage controlled it. They judged the suitor, set the labour, and admitted him or refused him. The practice turns up in societies speaking languages from deep and separate branches of Bantu, which puts it in place long before those branches parted. For thousands of years, across a third of the continent, this was ordinary.

Southern Cushitic speakers in East Africa domesticated the cowpea by the third millennium BCE, working independently of the West African farmers who had domesticated the same plant among Niger-Congo speakers. Two centres, two cultivated varieties, two language families, one continent, and both running at the same time. The West African variety is the one that travelled. It went east with the other African exports, reached India and kept going, and it is the cowpea that turns up in cuisines far from where it started. The East African domestication stayed close to home, which is why almost nobody has heard of it, and it is the more useful of the two facts for anyone trying to understand how agricultural invention actually works. Crop improvement went on in several African regions at once, in different ecological zones, among peoples of different language families, each of them responding to the ground in front of them.