Colin Barras examines how Neolithic Europe suffered a devastating conquest.
The sarsen stones of Stonehenge were erected some 4500 years ago but within a few centuries those who built it vanished, with almost every Briton from the entire country wiped out by incomers. DNA evidence is now informing what we know about these migrants.
A group of livestock herders called the Yamnaya occupied the Eurasian steppe north of the Black Sea and the Caucasus mountains. Between 5000 and 4000 years ago, they and their descendants colonised large areas of Europe, leaving a genetic legacy that persists to this day. Studies of archaeological finds shows that their arrival coincided with big changes in social and cultural behaviour, such as burial practices, and alongside this there appeared a warrior class and a sharp upturn in lethal violence.
Before about 5000 years ago, Neolithic Europe was prosperous, community-minded and relatively peaceful, occupied by farmers who worked together and built large stone structures, many of which were used as shared graves, with up to 200 burials. They were innovators, who it is thought had worked out how to use livestock to pull heavy loads, and may have had wheeled vehicles.
Staring about 5000 years ago in south-east Europe the dead started to be buried singly in 'pit graves', with the body decorated with ochre, a red pigment and the grave covered with wooden beams and a mound of earth, known as a kurgan. This burial custom was associated particularly with the Yamnaya. By 4900 years ago, the Corded Wear people (named after their distinctive pottery and adopting many other Yamnaya practices) began to appear in central and northern Europe.
Until about five years ago, the generally accepted theory was that this happened through the movement of ideas and technology while people stayed were they were. In 2015 geneticists suggested an alternative. It was discovered that occupants of Corded Wear graves in Germany could trace back about three quarters of their ancestry to the Yamnaya. They were not copying Yamnaya practices, they were largely Yamnaya in origin. This migration happened in just a few generations, and it is likely that this happened through a combination of disease, warfare and death.
Just before the Yamnaya arrived, Neolithic Europe was in crisis. Populations began shrinking about 5300 years ago. Studies of Neolithic teeth indicate plague-causing bacteria began spreading across Europe perhaps as early as 5700 years ago. When the settlements reached their greatest size, thousands of people lived in unhygienic conditions and in close contact with livestock.
The Yamnaya found a small and weakened indigenous population. Even so, the sheer speed of the change suggests that the migrants were dynamic and aggressive, perhaps mainly young male warriors as Yamnaya women seem to have joined the migration later. It is thought the incomers were horse-riders, and ancient DNA suggests they were unusually tall for the time. The males from outside displaced local males almost completely to the extent that only they fathered children. The latest genetic evidence reveals that they also went east into the Indian subcontinent.
Source: History of Violence by Colin Barras, New Scientist 30 March 2019
[I have elsewhere read about the behaviour of primates in Africa. Bonobos are generally peaceful and deal with disagreements by consensual sexual acts, while chimps carry out violent raids; the two species live in distinct forest areas and do not come into contact. Given human primate descent, it might be that a similar evolution happened, but the open land area of Europe allowed the Yamnaya to take over.]
