Infant feeding practices at the Pitted Ware Culture site of Ajvide, Gotland

The infant feeding practices used at the Middle Neolithic Pitted Ware Culture (PWC) site of Ajvide on the Baltic island of Gotland were investigated using carbon and nitrogen stable isotope ratio analysis. The PWC were marine hunters with a seal-based economy, but were contemporary with the farming Funnel Beaker and Boat Axe Cultures. The carbon and nitrogen stable isotope ratios of bone collagen from adult females (14 individuals) and bone and dentine collagen from subadult individuals (23 individuals, 55 samples) from Ajvide were analysed. The results (mean ± 1s.d.) were δ13C = −15.2 ± 0.4‰, δ15N = 15.6 ± 0.5‰ for the adult females, and δ13C = −15.3 ± 0.6‰, δ15N = 16.5 ± 1.1‰ for the subadults. The majority of infants continued breastfeeding into the third or fourth year of life. There was some variation in the types of supplementary foods used and the timing of their introduction, perhaps due to seasonal variation in the availability of different resources. The isotope ratios from one infant, a neonate, were indicative of a much more terrestrial diet than usually consumed by the PWC, suggesting contact with the contemporary farming populations. Comparison of the results from Ajvide to those from other PWC sites in the Baltic region reveals that both adult and subadult dietary practices differed slightly between sites.