Non-Local Enemies or Local Subjects of Violence?: Using Strontium (87Sr/86Sr) and Lead (206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb) Isobiographies to Reconstruct Geographic Origins and Early Childhood Mobility of Decapitated Male Heads from the Majes Valley, Peru

Throughout much of the pre-Hispanic Andes, bioarchaeological and iconographic evidence shows that the decapitation, dismemberment, and display of human heads were important aspects of ritual practices. Researchers have debated about the social identities of these decapitated heads—were they revered local ancestors, non-local enemies captured in raids or war, or locals injured in distant combat partially repatriated for home burial—answers which have distinct implications for understanding the motivations and social contexts of this practice. We describe trophy-taking and trophy-making from the Uraca cemetery in pre-Hispanic Arequipa, Peru. To determine whether these trophies were locals, we employ radiogenic isotope analyses ( 87 Sr/ 86 Sr, 206 Pb/ 204 Pb, 207 Pb/ 204 Pb, 208 Pb/ 204 Pb) of tooth enamel from 37 individuals (25 non-trophies and 12 adult male trophies). To understand the degree of childhood mobility that occurred and whether that differed between individuals who became trophies and those who did not, we also examine 87 Sr/ 86 Sr, 206 Pb/ 204 Pb, 207 Pb/ 204 Pb, 208 Pb/ 204 Pb in paired teeth from infancy/early childhood and middle childhood of 18 individuals (8 non-trophies and 10 trophies). Results show that 20% of the non-trophies and 75% of the trophies were non-local relative to modeled local 87 Sr/ 86 Sr and mean (± 2 SD) of lead isotope values. Intra-childhood differences show that the individuals who became trophies experienced more childhood mobility than non-trophy individuals. This suggests Uraca’s external interactions and mobility were structured by violent intergroup raids and warfare throughout the region. Ongoing analyses will extend Uraca’s residential isobiographies to adolescence and late-life, refine the expected range of isotope ratios in the region, and clarify the extent of Majes Valley mobility during the mid-first millennium CE.