The stones date from 23,000 to 19,500 years ago, late in the last ice age. But the earliest archaeological evidence for crop cultivation in China is 11,000 years old, suggesting that farming was slow to emerge from ancient traditions of plant use.
That fits with a wider pattern, says Robin Allaby of the University of Warwick, UK. In the Middle East “we also have evidence of cereals at that 23,000-year point”, he says – which is long before people were farming them. “Although this period is around the late glacial maximum, there is a blip at 23,000 years during which time it was milder.” Millet and the other food plants could have flourished in the warmth, tempting people to start exploiting them.
Story: Colin Barras, NewScientist | Photo: Li Liu