Pre-literate ancient societies seldom left us with much evidence of gender roles, but one team of researchers have found an innovative way to study the prehistoric division of labor. They've used prints left by potters' fingers to show the ratio of men and women in this important trade shifted with time, challenging the idea that men's and women's work was fairly fixed in pre-industrial societies.
Usually when scientists refer to “finding a fingerprint”, they mean it metaphorically, unless they are in forensics. However, Dr John Kanter of the University of North Florida has used actual fingerprints on 1,000-year-old pottery from America's south-western Ancestral Puebloan community, an ancient Native American culture, to determine who the potters were.
Naturally, we can't match prints to specific long-dead individuals, but Kanter used the fact the ridges are, on average, further apart on men's fingers than women's to establish which sex worked the clay.
Although our fingerprints are unique, patterns can be found, such as common features in closely related individuals. Moreover, ridge spacing correlates with biological sex well enough it can be used to identify the sex of the person who left a print with 80-90 percent accuracy, with the middle three fingers particularly reliable.
Imperfect as this is for an individual case, it's quite sufficient to reveal if a large sample of prints mainly came from men or women.
Kanter collected 985 shards of pottery from Chaco Canyon, which became a powerful religious and political center of the American Southwest around 1,000 years ago, filled with buildings five stories high. Much of Chaco's pottery was made by pinching clay paste together to form “corrugated” vessels. Fingerprints the potter left in the clay frequently survived both the firing and years of use.

The first Europeans to arrive in the southwest described pottery there as being mainly made by women. More recent anthropologists have recorded the same thing among surviving Native American communities, and extrapolated this back to the height of what is known as the Ancestral Puebloan civilization.
However, Kanter found 47 percent of the shards were made by distinctively male hands, 40 percent by women (or possibly children) and 13 percent had ridge gaps in an intermediary range, preventing identification.
On its own this refutes the assumption of pottery as a specifically women's job, but in Proceedings of the National Academy of Sciences Kanter goes further. Two-thirds of shards dating from before 1040 CE carry predominantly male prints, Kanter found, but those in subsequent layers were evenly split. Geographical divisions in gender roles were also identified.
Besides demonstrating archaeologists' creativity, the findings have implications far beyond a single society, showing ancient gender roles were much less fixed than we assume if we only look at one moment in time.
