Early Childhood in Precolonial South America: Breastfeeding, Infant Mortality, and Stable Isotopes Analysis in Southeastern Shell Mound Builders During the Middle Holocene (7th–5th Millennium BP)

ABSTRACT This article presents and discusses isotopic data on breastfeeding, weaning, and complementary diet during early childhood in Middle Holocene southeastern Brazil. The study focuses on human individuals from two contemporaneous shell mounds, Piaçaguera (7151–5668 yBP) and Moraes (6791–5590 yBP), which show distinct patterns of infant mortality. We conducted δ 15 N and δ 13 C analyses on collagen extracted from subadult bones (Piaçaguera: n = 13; Moraes: n = 13) and sequential dentine slices from permanent (Piaçaguera: n = 7; Moraes: n = 11) and deciduous teeth (Moraes: n = 5). Our findings indicate that weaning ended between 2 and 4 years old in Piaçaguera, with complementary foods similar to the adults. At Moraes, weaning ended between 2 and 5 years old, with a higher consumption of freshwater fish during early childhood and by pregnant women. The weaning ages at Piaçaguera and Moraes align with those documented in other precolonial South American groups. However, our study suggests different dietary preferences and strategies within each group, possibly linked to distinct patterns of infant mortality, particularly evident in the Moraes group.