A multi-isotopic (δ13C, δ15N, and δ34S) faunal baseline for Maya subsistence and migration studies

Abstract

Subsistence practices and migration among the prehispanic Maya have been extensively studied using multiple isotopic techniques, although stable sulfur isotope (δ34S) analysis has been minimally applied in the Maya archaeology. This study compares expected variation in δ34S values in the Maya region with the values from 148 faunal specimens to create a sulfur isotope baseline for the Northern and Eastern lowlands. These data are combined with stable carbon (δ13C) and nitrogen isotope (δ15N) results to investigate the diets and identify nonlocal animals at Maya sites located in Belize, Guatemala, and Mexico. The δ13C and δ15N results are consistent with those of previous Maya archaeological faunal studies. The sulfur isotope data indicate that terrestrial, marine, and freshwater ecosystems exhibit different values, which were used to evaluate the hypothesized variation in δ34S values in this part of the Maya region. Marine taxa δ34S values were likely influenced by dissimilatory sulfate reduction (DSR) and freshwater sulfur inputs in coastal areas. The δ34S values of freshwater taxa similarly reflect the influence of DSR, but also the variable sulfur sources in freshwater ecosystems. The terrestrial fauna from coastal sites had δ34S values influenced by marine sulfate deposited by sea spray. The δ34S values of inland terrestrial animals overlap those from coastal sites due to the underlying limestone geology derived from marine evaporites. Eight terrestrial faunal δ34S values from six sites were statistical outliers, representing nonlocal animals that were exchanged from isotopically distinct regions. The results suggest δ34S values may differentiate between Maya consumption of terrestrial- and freshwater-based dietary protein and can identify nonlocal animals and, by extension, humans. This study presents the first extensive archaeological faunal sulfur isotope baseline for Mesoamerica and for a tropical continental setting in general. These results demonstrate a multi-isotopic framework that includes sulfur isotope analysis can provide important insights into Maya subsistence practices, migration, and animal exchange.