A set of ancient skeletons discovered in Germany has demonstrated that, just like the Flintstones, Stone Age humans formed nuclear families.

Genetic analysis of four bodies found in a 4,600-year-old grave shows that they belonged to a mother, a father and their two sons, who were buried together in one another’s arms.

The Neolithic remains, which belong to a man aged between 40 and 60, a woman aged between 35 and 50, and boys aged 4 to 5 and 8 to 9, provide the earliest firm evidence for the existence of nuclear family units.

They may also bear witness to an ancient massacre: they were interred along with nine others in four graves, and many of the bodies show signs of a violent end. One female had a stone projectile head embedded in a vertebra, another had a fractured skull, and others had cut marks on their hands and forearms consistent with self-defence.

Most of the dead were children or women, and only one of the bodies belonged to a man in his prime, aged between 25 and 40. It is likely that these people were murdered in a raid by a rival tribe, before the survivors returned to bury their dead.

A second grave may also hold a less conventional family unit: it contains the bodies of an infant girl, two brothers aged 4 to 5 and 7 to 9, and a woman aged between 30 and 38.

DNA tests show that the two boys were probably brothers, and although the woman could not have been their mother, she is thought to have been a paternal aunt or stepmother. The baby’s body has been too badly preserved for a family relationship to be established.

Wolfgang Haak, of the University of Adelaide, who led the research, said that in each grave, the bodies were arranged in positions that appear to have been symbolic of their relationships. In the case of the nuclear family, the man and woman were placed face to face with arms and hands linked, and the two boys were also facing one another. This is unusual for graves from this period, known as the Corded Ware Culture after its typical pots decorated with twisted cords.

Details of the excavations, at Eulau, in Saxony-Anhalt, Germany, are published in the journal Proceedings of the National Academy of Sciences.

Dr Haak said the findings suggest that nuclear families were recognised as social units by the Corded Ware Culture, though this may not have been the dominant arrangment.

“In Eulau, we have established the presence of the classic nuclear family in a prehistoric context in Central Europe,” he said. “However, this does not establish the elemental family to bea universal model or the most ancient institution of human communities. For example, polygamous unions are prevalent in ethnographical data.”

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