Carbon and nitrogen stable isotope analysis of hunter–gatherers from the Coleman site,a Late Prehistoric cemetery in Central Texas

We report on a stable isotopic analysis of 17 hunter–gatherer burials from the Coleman site (41BX568), a Late Prehistoric Toyah Interval (700–350 years BP) occupation in Texas. Prior to our analysis, isotopic research on Toyah populations in Central Texas was represented by a single burial at site 41BX677. That burial showed an isotopic pattern suggestive of a diet heavily focused on CAM/C₄ plants and C₄ fauna. Coleman burials show a different pattern. While interpretations are complicated by high variability in the isotopic signatures of children and by differences in male and female diets possibly related to mate exchange, the 11 adult and adolescent burials at Coleman show a diet focused on C₃ fauna and the use of both C₃ and CAM/C₄ plants. The moderate CAM/C₄ plant use is a radical departure from a trend of increasing C₃ plant use that characterized hunter–gatherers in this region for at least 6200 years prior to the start of the Toyah Interval. Protein sources among Coleman adults probably centered on deer, but also included high nitrogen (δ¹⁵N) animals, such as fish. Males seem to have differential access to these high nitrogen sources. Two different isotopic patterns, one reflecting a focus on C₃ fauna and moderate use of CAM/C₄ plants, and a second reflecting C₄ fauna and extensive use of CAM/C₄ plants, are represented during Toyah. While interpretations are complicated by small sample sizes, these two patterns could simply reflect temporal differences, different acquisition strategies based on availability, or hint at different subsistence strategies. It may also be the case that the 41BX677 individual represents an immigrant into the Central Texas region, one with a different isotopic history.