A dried clump of human feces and the traces of human muscle protein on a cooking pot are proof of prehistoric cannibalism in the American Southwest about 850 years ago, according to a team of scientists.
The findings are the latest analysis of a site near Cowboy Wash in southwestern Colorado, a Pueblo village that was suddenly abandoned around A.D. 1150. It is one of several dozen ancient village sites in the region that archaeologists say show signs of violent death and human consumption of human flesh.
Prepared as Food
Until recently, the evidence for cannibalism had been circumstantial, but significant by archaeological standards. Previous excavations revealed seven bodies at the site had been dismembered, broken apart and scattered directly on the household floor at a time when the dead were normally buried outside the house in a fetal position.
The skeletons also showed signs that they had been prepared as food. Archaeologists found cut marks from tools used to butcher meat from bone, scorching on bones where they had been exposed to open flame and “pot polish” — the tell-tale burnish at the ends of bones that have been worn from rubbing against the inside of a cooking pot.
But it is the biochemical analysis of dried human excrement — known as a coprolite in archaeologist parlance — found in one of three pithouses at the site that is most convincing, say the authors of a study published this week in Nature. In the excrement, researchers found a protein that could only come from the consumption of human flesh.
“The evidence clearly demonstrates that in the past, someone consumed human flesh at the Cowboy Wash site,” says Richard Marlar, a biochemist at the University of Colorado School of Medicine and an author of the study.
“Eight to 16 hours later,” he says, “the person that ate that food defecated into the central fireplace. It may have been the final desecration of the site, or the degrading of the people that lived there.”
Marlar and his colleagues found a human protein called myoglobin in the unburned human feces, which had been deposited in the fireplace after its final use. Myoglobin is protein that transports oxygen from the membrane of muscle cells to the energy-producing parts of cells. It is only found in heart muscle and muscles that attach to bone, says Marlar.
The scientists chose the protein myoglobin because it is not found in human stool material, even from the natural shedding of cells in the digestive tract, says Marlar. The team also used a technique that could distinguish human myoglobin from that of other animals in the area — such as deer, rabbit and bison — that would have been routinely consumed by Puebloan people.
Along with the fecal material, pieces of a recovered Cowboy Wash cooking pot tested positive for myoglobin. This finding was consistent with the smoothed ends of some bones that had most likely rubbed against the inside of the pot as they stewed.
Violent and Hungry
Many scholars have been skeptical of evidence that points to cannibalism because there are no historic accounts that Southwestern Indian people engaged in the practice, says Brian Billman, an archaeologist at the University of North Carolina at Chapel Hill and project director at the excavation in the mid-1990s. Other experts have suggested that what appears to be cannibalism may have been the ritual killing of individuals thought to be witches or enemies, or the mutilation of corpses.