Genetic analysis reveals kinship in ancient Moche sacrifice

Harvard University-led researchers investigated an elite Moche burial group at Huaca Cao Viejo, uncovering new details on kin-based status within Moche society. The evidence centers on four generations of a family dated to approximately 500 CE, with genetic data connecting the Señora de Cao to a sibling, a grandparent, and two sacrificed juveniles.

Moche culture thrived along Peru’s North Coast between the 4th and 10th centuries CE, constructing monumental adobe temples (huacas) and complex irrigation networks. Previous archaeological work has hypothesized kinship as a factor in high status and political influence.

Genomic evidence was required to verify whether Moche elites were indeed buried with close relatives and whether sacrificial victims shared direct biological ties with principal tomb occupants.

In the study, “Family relations of Moche elite burials on the North Coast of Peru (~500 CE): Analyses of the Señora de Cao and relatives,” published in PNAS, researchers set out to confirm or reject earlier hypotheses.

Examination of pyramid-like tomb structures in the Chicama Valley revealed six individuals placed in four burials. Investigators extracted and sequenced ancient DNA from the teeth and bones of all six individuals. Radiocarbon dating places five of those remains around 500 CE, while one grandparent figure predated the others by several decades and was likely reburied to accompany the group.

Stable isotope ratios of carbon, nitrogen, oxygen, lead, and strontium established dietary patterns and geographic origins.

Analysis of carbon isotopes indicated that most elite group members consumed a diet heavily reliant on C4 plants, such as maize, constituting approximately 70% of their plant intake. Nitrogen isotope ratios suggest that their protein intake included substantial amounts of marine protein, estimated between 45% to 70%.

Strontium isotope ratios (87Sr/86Sr) for most members of the elite group aligned with local values consistent with the Chicama Valley. The sacrificed juveniles exhibited distinct strontium ratios that diverged from the local values, indicating origins from a different geographic region.

Lead isotope ratios reinforced this finding, with one of the juveniles (called B3s) presenting as an extreme outlier compared to the other individuals, further supporting her nonlocal origins. Oxygen isotope ratios for B3s were relatively low, consistent with an inland or highland upbringing.

B3s contrasts with the others, who all showed signatures of residence near the Chicama Valley. Without genetic evidence, this might suggest that B3s was unrelated to the others.

Genetic results confirmed close ties among the individuals, including a sibling relationship between an adult male and the Señora and a parent-child link between that male and his sacrificed son.

The female juvenile, B3s, was also identified as a second-degree relative of the Señora. With isotopic signatures pointing to a distant childhood setting, B3s suggests that Moche familial connections persisted across great distances.

Analysis of burial offerings, such as layered textiles and ceremonial clubs, affirmed elite standing for all adults, though the juveniles were mostly unadorned.

The Señora de Cao possessed the most lavish regalia, including crowns, tiaras, clubs, nose and ear rings. Her skin still bears tattoos of spiders and snakes, signs that she may have been a healer or spiritual leader. Her importance is remarkable for a woman who was only 25 at the time of her death.

Reburial of an earlier ancestor in the same enclosure hints at a social emphasis on honoring past generations and consolidating power through maintained ancestral presence.

This honoring seems to carry much less weight when considering future generations, as the forensic archaeology of the site supports a brutal pattern of ritual strangulation for the juveniles. Placement of the sacrificed children with elite kin demonstrates that wealth and authority were intertwined with family ties, even in death.

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