Animal herders living in what was a grassy part of North Africa’s Sahara Desert around 7,000 years ago had a taste for cattle milk, or perhaps milk products such as butter. Researchers have identified a chemical signature of dairy fats on the inside surfaces of pottery from that time.
Dairy products played a big part in the diets of these ancient Africans, even though they did not live in farming villages as the earliest European milk users did, reports a team led by biogeochemists Julie Dunne and Richard Evershed, both of the University of Bristol in England.
Dairying may have spread from the Middle East and nearby areas — where farming emerged around 10,000 years ago — to Africa and Europe within a couple thousand years, the scientists propose in the June 21 Nature.
Chemical evidence shows that cattle milked in the ancient Sahara ate plants from both cool, wet areas and hot, dry expanses. “Animals were being moved around the landscape between different ecosystems containing different plants, possibly as a result of seasonal variations in available pastures,” Evershed says.
Researchers generally assume that North Africans domesticated cattle, sheep and goats before growing crops. Previously excavated bones of domesticated animals date to roughly 8,000 years ago in North Africa. Rock paintings in the region depict cattle herding and a few instances of milking, but no reliable dates exist for these artworks.
An early date for dairying in North Africa “implies that one of the reasons local African peoples adopted cattle was for their milk products,” says anthropologist Diane Gifford-Gonzalez of the University of California, Santa Cruz.
A 2008 pottery study led by Evershed placed the origins of cattle milking in what’s now northwestern Turkey at about 9,000 years ago.
Farming, raising animals, dairying and making pottery all apparently spread across Europe at the same time, says anthropologist Kevin Gibbs of the University of Aberdeen, Scotland. In contrast, the new study shows that Saharan herders adopted cattle and dairying into a nomadic lifestyle after having made pottery for several thousand years.
Some African groups possess genetic mutations that enable milk drinking without nausea and other unpleasant reactions to lactose, a sugar found in milk. These mutations commonly appear in Europeans, whose farming ancestors used milk at least 6,000 years ago (SN: 2/1/03, p. 67).
“We could be looking at multiple origins for dairying,” remarks bioarchaeologist Oliver Craig of the University of York, England.
Dunne and Evershed’s group identified different forms of carbon in small, ground-up samples taken from 81 pottery fragments previously found at a Libyan rock shelter and mostly dating to between 7,200 and 5,800 years ago. Each specimen contained carbon with a distinctive signature found in milk fats. Further chemical comparisons to milk fats from grazing animals now living in Africa showed that ancient Saharans milked cattle, but not goats or sheep.Large amounts of dairy fat on the African pottery reflect either good preservation in arid conditions or the use of fat-rich products such as butter that store well and can be digested by lactose-intolerant individuals, Craig says.