Using stable nitrogen‐isotopes to study weaning behavior in past populations

Several different methods have been used to explore weaning behavior in past populations, including demographic profiles, non‐specific osteological indicators of stress, and bone chemistry studies. Stable nitrogen‐isotope ratios of prehistoric bone proteins provide an especially useful method for reconstructing the weaning patterns of archaeological populations. A demographic measure of fertility (the D30+/D5+ ratio) is compared with age‐related changes in stable nitrogen‐isotope ratios for human burials from one historic cemetery and two prehistoric ones. The stable nitrogen‐isotope ratios show that each population had a characteristic and distinctive combination of weaning time and rate, and that neither the timing nor tempo of weaning was clearly correlated with the demographic measure of fertility. These results demonstrate the feasibility of using stable nitrogen‐isotope ratios to compare weaning patterns and fertility in past populations. This example also shows that the relationship between fertility and weaning behavior is complex.