Diet and Migration in Prehistoric Remote Oceania

Abstract

The human processes of food production and migration are intertwined and of utmost importance in the tropical Pacific, where generally depauperate islands predicated the need for effective cultural adaptations in order for settlements to thrive. This thesis investigates movement and diet of individuals from two prehistoric burial sites in Remote Oceania. Stable isotope analyses (δ13C, δ15N, δ34S) of bone collagen were conducted to examine diet within the last few years of an individual's life, while dentine collagen analysis provided information about childhood diet. Oral conditions (caries, macrowear, calculus, chipping, periodontitis, alveolar lesions, and ante-mortem tooth loss) were also examined as dietary indicators. Strontium analysis (87Sr/86Sr) of tooth enamel was conducted to investigate childhood residence, identify likely migrants, and consider cultural forces that may have affected movement in the past.

The first collection (n = 28) is from the coastal site of Bourewa in the Republic of Fiji. Bourewa contained burials dated to the Vuda phase (c. 750-150 BP), a period in which climatic fluctuations in Fiji potentially dramatically affected food resources. The second skeletal collection (n = 126) are from the `Atele burial mounds on the Tongan island of Tongatapu (c. 500-150 BP). The first burial mound (To-At-1) could be classified as a commoner's burial mound while the second mound (To-At-2) was possibly used as a chiefly burial place. The possibility of diet and mobility reflecting status differences in these mounds are explored. To-At-1 and To-At-2 contained a large proportion of subadults: the bone collagen of children and adolescents yields information about the diet of those who did not survive to adulthood.

Potential differences in isotope values and oral conditions frequency are explored between the sites, burial mounds, sexes, and age groups. These findings are interpreted within the biocultural context of late prehistoric social, political, and ecological environments and compared to past Pacific studies, placing the interpretations in a wider context. Bourewa individuals relied more heavily on marine foods compared to `Atele individuals as evidenced by significantly higher δ13Cbone values, less severe caries, and more severe wear. Stable isotope values from the `Atele burial mounds suggest To-At-2 adults consumed proportionately more terrestrial foods than To-At-1 adults. Dentine and bone stable isotope values from both Bourewa and `Atele adults differed significantly, suggesting childhood and adult diet variation. Caries prevalence did not differ between the sexes in either site (though in `Atele there were significant sex-based differences in paleodietary isotope values). This lack of sex-based differences in caries prevalence is at odds with the global trend of females displaying higher caries rates.

Only one immigrant within each site was detected using 87Sr/86Sr analysis. Most displayed 87Sr/86Sr ratios expected for people living along a marine coastline. Paleodietary isotope values of a childhood diet different from the rest of the population served as supplementary evidence for pinpointing immigrants. This method identified two other Bourewa individuals who lived inland during childhood. With only one non-local in `Atele, religiopolitical control may have restricted who entered (and was buried on) the sacred island of Tongatapu.