Occasional Hunts or Mass Kills? Investigating the Origins of Archaeological Pronghorn Bonebeds in Southwest Wyoming

Abstract

It is often unclear whether an archaeological animal bonebed was formed by a mass kill of individuals from a single prey population or through the accumulation of a number of separate kills which occurred over a long time period or at multiple locations. The isotope ratio variation within animals from an archaeological bonebed can be used to investigate this question by comparing the isotope ratio variation within an archaeological assemblage to the variation within modern populations. If the archaeological variation exceeds that expected within a single population, then an accumulation is indicated. Otherwise, a single mass kill or a series of kills from a single population over a fairly short time period is more likely. This technique is demonstrated using carbon, oxygen, and strontium isotope ratios to characterize the amount of variation within pronghorn tooth enamel from six archaeological sites in southwestern Wyoming. The results indicate that the Austin Wash and Trappers Point sites are the result of an accumulation of pronghorn from multiple populations, while the Firehole Basin, Gailiun, and Boars Tusk sites do not show evidence of accumulation and therefore may be the result of mass kills. The Eden-Farson site formation characteristics are currently indeterminate.