Assessment of Age at Weaning for Post-Contact Maya of Tipu, Belize, Using Stable Carbon, Nitrogen, and Oxygen Isotope Ratios
Master of Arts (MA)
Geography and Anthropology
Age at weaning was assessed for a post-Spanish contact Maya population, the Tipu, by sampling 25 individuals (20 subadults less than seven years of age and five females from 18 to 45 years of age). Whole ribs, for younger subadults, and rib fragments, for older subadults and adults, were sampled for stable nitrogen, carbon, and oxygen isotope ratios. Five lines of evidence were used to assess age at weaning: stable carbon composition from collagen (δ13Ccol), stable nitrogen composition from collagen (δ15Ncol), stable carbon composition from apatite (δ13Cap), difference in collagen and apatite composition (Δ13Cap-col), and stable oxygen composition from apatite (δ18Oap). The subadults interpreted as breastfeeding at time of death were those that displayed the trophic level effect: δ15Ncol elevated 2‰ to 3‰ above the stable nitrogen composition of the adult females and δ13Ccol elevated ~1‰ above the stable carbon composition of the adult females. For this study, three subadults less than one year, one aged one to two years, and one aged two to four years displayed the trophic level effect. The other lines of evidence (i.e., δ13Cap, Δ13Cap-col, and δ18Oap) suggest individuals less than one year of age consumed a diet of breast milk, while other subadults consumed a diet equivalent to the mother’s before two to four years of age. Breast milk and maize have similar carbon content, and therefore, the δ13Cap varied little between the subadult categories and the adult females. The difference between collagen and apatite (Δ13Cap-col) increased as maize consumption in the subadult diet increased and breast milk consumption decreased. Lastly, δ18Oap decreased as the subadults increased their consumption of environmental water. Though ethnohistoric data suggest that individuals at Tipu were weaned between three and four years of age, data from this study suggests that individuals at Tipu may have been fully weaned by two to three years of age.
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Hiers, Chaney, "Assessment of Age at Weaning for Post-Contact Maya of Tipu, Belize, Using Stable Carbon, Nitrogen, and Oxygen Isotope Ratios" (2014). LSU Master's Theses. 1372.