New insights into the marine contribution to ancient Easter Islanders' diet

Easter Island (or Rapa Nui), internationally renowned for its megalithic statues, is the most isolated inhabited island of the Pacific. Archaeological surveys undertaken from the end of the 19th century led to the discovery of the remains of several hundred human individuals. The majority were buried in monuments (funerary stone platform called ahu) or in caves. This paper presents a study of the ancient Easter Islanders' diet through carbon and nitrogen stable isotope analysis of human tooth and bone collagen and, more particularly, evaluates the impact of gender, age, social status and location of burials. The 125 studied individuals are from 16 sites, which date mainly from the 17th to the 19th centuries. This anthropological material is housed at the Royal Belgian Institute of Natural sciences and the Father Sebastián Englert Anthropological Museum of Easter Island. One hundred and seven individuals showed well-preserved collagen. The stable isotope data provide new information on ancient Easter Islander dietary habits. They demonstrate gender disparity in access to food resources and show that children were breastfed until 3 years of age. Furthermore, the isotopic signatures cluster according to the place of burial (ahu) indicating family dietary specificities. Finally, our study reveals influences of social status on food intake: individuals from Ahu Nau Nau, which is said to be the royal ahu, display the highest nitrogen and carbon isotope values. A greater consumption of marine products may explain this distinction.