Stone Age hunter-gatherers in Europe may have been trading with settled farmers as long as 7,000 years ago -- acquiring pigs to supplement their hauls of wild boar, scientists said Tuesday.
A study in the journal Nature Communications claims to provide the first evidence of live animal trade between the indigenous, nomadic Ertebolle hunters of northern Europe and more advanced, settled farmers who originally came from the Fertile Crescent -- today's Turkey, Syria and Iraq.
"Hunters and farmers were not only acquainted with each other but even traded live animals," said a statement from Germany's Kiel University, which contributed to the study.
Hunter-gatherers and farmers co-existed in northern Europe from about 5,500 to 4,200 BC.
The hunter-gatherers lived off seals and wild boar on the western Baltic coast, while the farmers cultivated crops and livestock south of the Elbe River that runs through central Europe.
The two groups are believed to have made sporadic contact, as suggested by excavated axes and pottery resembling those of the farmers at hunter-gatherer settlements, but the nature and extent of the exchanges remain a mystery.
There has been no previous evidence that the hunters had access to any domestic animals other than dogs.
For the new study, a team analyzed DNA from pig remains unearthed at different Ertebolle settlements. They found the swine had maternal ancestors from the Middle East, like the domestic pigs of their farmer neighbors across the river.
"Members of the Mesolithic (middle Stone Age) Ertebolle culture already had domestic pigs as early as 4,600 B.C., although they were -- as hunters and gatherers -- not yet familiar with animal husbandry," said the statement.
"Ertebolle hunter-gatherers acquired domestic pigs of varying size and coat color, added the study.
Some of the Ertebolle pigs had a light-colored coat with black spots -- a typical feature of domesticated swine and completely different to the inconspicuous grey coat of the wild boar they would have been more familiar with.
The researchers concluded that the two groups likely traded with one another, though they could not rule out livestock theft as a possible explanation.
"Although it is unclear why the Ertebolle sought domestic pigs, both large and small pigs with multicolored coats would likely have seemed strange and exotic compared with the more familiar appearance of the locally available wild boar they traditionally hunted," the team reported.
Their acquaintance with domestic pigs did not immediately revolutionize the hunter-gatherer lifestyle, however.
The Ertebolle continued hunting wild prey for hundreds of years after they started raising a few domestic pigs, before finally settling down to farm full-time.
The study also showed that domestic pigs were present in the region some 500 years earlier than previously thought.