Horticultural intensification and plant-based diets of 18th century CE Waikato Māori in Aotearoa New Zealand

In Aotearoa New Zealand, Māori oral histories, ethno-historical accounts, and archaeological evidence indicate that kūmara (sweet potato; Ipomoea batatas) and taro (Colocasia esculenta) horticulture were key drivers of population growth and cultural change. We investigate diet, childhood residency, and chromosomal sex of Māori tūpuna (ancestors) who were discovered accidentally during roadworks in the Waikato region, an area with widespread evidence for intensive horticulture from the sixteenth century CE. The kōiwi tangata (human remains), dated to ca. 250-170 cal BP, were interred as a commingled secondary burial in a borrow pit during the Traditional Period of Māori history, a time characterized by highly distinctive art, architecture, cosmology, and whakapapa (genealogy). Using isotope and enamel peptide analyses we find that all seven tūpuna relied primarily on plant foods. Two children (chromosomally male and chromosomally female, respectively) were likely local and weaned onto plant foods within the first two to three years of life. These findings demonstrate that horticulture was central to life in the Waikato during the Traditional Period, to the extent that some individuals ate predominantly plant-based diets.