Scientists have discovered that North African people have been making yogurt for more than 7,000 years, thanks to an analysis of pottery shards which was published in the journal Nature. Yogurt left tell-tale traces of fat on the ceramic fragments, which suggests that it might have been a way for these people to tolerate milk as adults.

The earliest dairying dates back to 9,000 years in Anatolia, but the new findings from 7,000 years ago predate the emergence and spread of the gene variants needed for adults to digest the lactose found in milk. Richard Evershed, a biomolecular archaeologist at the University of Bristol, led the study.

Evershed thinks that the people in North Africa processed the milk to lower the lactose content, making it more digestible. Evershed and his team analyzed pottery shards dating from 5200 to 3000 BC from the Takarkori rock shelter in southwestern Libya, in the Acacus mountains. In this area, there are vivid representations on rocks depicting cattle, with full udders. There are even pictures of people milking cattle. These pictures have proven difficult to date precisely. This is why the team turned to the pottery shards.

The scientists examined 81 shards using mass spectrometry to identify certain animal fats. They were able to pick out the exact origin of 29 of these samples, all of which contained fats that came from dairy food.

The carbon isotopes found in the milk fat also points out that the animals ate a lot of different plants, suggesting that the people might have let the cattle graze and then moved them around a lot. The mutations that arose in adults to allow the digestion of lactose arose 7,000 to 8,000 years ago in Europe, and later spread to Africa. Fresh milk is an uncontaminated source of fluid, and the people who were able to tolerate lactose stayed better hydrated than those who didn’t have the gene.

[via Nature]