Did milk play a major role in Bronze Age migrations?

Photo: horses on the Pontic steppes. Credit: a. Senokosov

The Pontic Steppes, an area between the Black and Caspian Seas, was home to a people we know today as the Jamna culture. Sometime in the Bronze Age, about 5,000 years ago, the Jamna spread east and west, a mass migration that left a distinct genetic imprint from Scandinavia to Siberia.

How our Jamna reached such vast distances across sparsely populated steppe regions remains unclear, said Professor Shivan Wilkin, a molecular biologist specializing in fossil proteins affiliated with the Max Planck Institute. A large genome study conducted a few years ago revealed the size and impact of this migratory wave, but not how they managed to cross the steppe. People lived there at that time, but no more than a few small groups of hunters and gatherers. Hunting or gathering cannot support this great wave of migration.

This gave Wilkin the idea that dairy products could be the key to this wave of migration. Milk and dairy products have a number of important advantages. They are not only a good source of proteins, carbohydrates and fats, but also moisture. Milk, whether fermented or not, is made up of more than 90 percent water. Dairy products are also available in winter, and there is no need to kill livestock for food. It is a source of nourishment that moves with you.

Wilkin and her team analyzed the painting from the skeletons of our bridle. The plaque retains the proteins from the food eaten at that time. This analysis of dental plaque makes it possible to look at the consumption of dairy products at an individual level. Not only that, but it also shows which animal the milk came from. Conserved proteins of ruminants can be broken down into smaller elements called peptides. Most of these peptides are the same for all ruminants, but some are different. The data showed that Jamna actually switched to dairy products at some point, mainly from cows, sheep and goats, but also from horses.

How Jamna came to transform into cattle and dairy is not completely known. The peoples who preceded them on the Pontic Plains were hunters and gatherers who kept some animals, but certainly not for dairy. Animal husbandry and dairy products were already popular among other peoples in Europe and Turkey. There is no known direct migration to the Pontic steppe of people who already have livestock in other areas. But cultural exchange is possible. Anyway, as soon as Jamna switched to animal husbandry and dairy consumption, they themselves rushed over a vast area.