Isotopic Evidence of Weaning in Hunter-gatherers from the Late Holocene in Lake Salitroso, Patagonia, Argentina

TESSONE, AUGUSTO; GARCÍA GURAIEB, SOALNA; GOÑI, RAFAEL AGUSTÍN; PANARELLO, HÉCTOR OSVALDO

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY

WILEY-LISS, DIV JOHN WILEY & SONS INC

Lugar: New York; Año: 2015 vol. 158 p. 105 - 115

0002-9483

Objectives: The timing and duration of breastfeeding and weaning in past hunter-gatherer populations are discussed based on the results of stable carbon and nitrogen isotope analyses undertaken on a Late Holocene skeletal sample from Lake Salitroso in the Patagonian steppe (Argentina). Research in Lake Salitroso is part of a regional project that studies the Relationship between hunter-gatherer societies, their organizational systems and the environmental changes during the last 3,000 years in Patagonia. Methods: The sample included 52 individuals: 33 subadults and 19 adults of both sexes. They were recovered from 24 burial stone structures -locally called chenques-, with dates ranging from ca. 800 BP to 350 BP. Ribs were selected for collagen extraction and measurement of 13C/12C and 15N/14N ratios. Results: A 13C mean value of -18.7 ± 0.5 was obtained, with a range between -19.8 and -17.1 whereas 15N recorded a mean of 11.9 ± 1.1 with a range between 10.1 and 14.8. 15N data showed an age-related pattern with particularly marked difference between values for subadults under the age of 4 and older individuals. As opposed to 15N, 13C showed little variation with age. Conclusions: An early incorporation of supplementary solid food between 0.75 and 2 years of age and a late cessation of breastfeeding at about 5 to 6 years of age were inferred. This suggests that among this Patagonian hunter-gatherer population weaning was a gradual and lengthy process. These results are consistent with the patterns observed in cross-cultural studies and archaeological samples of hunter-gatherer groups.