Of the plants that grow in this part of China, millet is one of the few that contains the heavy carbon isotope known as C4 — most other plant foods have the lighter C2 isotope. The researchers found that most of the dog bones dating right back to the earliest phases at the site bore the C4 isotopic signature, suggesting that they were domesticated and being fed by humans (millet is not a grain that wild dogs eat in large quantities).
Bones of pigs from the site tell a slightly different story. The Phase 1 pig bones (7,900 to 7,200 years ago) showed no signs of millet in the diet, whereas the Phase 2 bones (6,500 to 4,900 years ago) do, suggesting that the earlier bones are of wild pigs and that pigs had been domesticated by the later phase of occupation.
‘Our results help fill in the picture of how agriculture arose in this part of the world,’ says Newsome. ‘There has been speculation that agriculture spread north from southern rice-farming areas, but the Phase 1 people were experimenting with agriculture by cultivating local grains. This simple system was later replaced in Phase 2 by a much more developed agricultural system.’ •
This article is an extract from the full article published in World Archaeology Issue 35. Click here to subscribe