Costly Signaling and Changing Faunal Abundances at Five Finger Ridge, Utah

Abstract

This research attempts to develop and test a series of predictions for identifying costly signaling forms of hunting in the prehistoric past. I predict that signaling hunters should place increasingly greater value in species that have become more rare on the landscape, while non-signaling hunters should respond by increasing their diet breadth. These animals may be identified from the archaeological record using taxonomic and skeletal part abundance measures combined with strontium isotope values to show that hunters were traveling further abroad when local populations became locally scarce. Since species with high signaling value should be widely shared in order to maximize the hunter’s signal to a broad audience, I also argue that taxonomic and skeletal part richness and evenness measures may be used to distinguish different forms of sharing.

I used the fauna from Five Finger Ridge, a Fremont site in the eastern Great Basin, to test these predictions. I found that density-mediated bone survivorship varied across taxa and site contexts, preventing the identification of behaviorally-meaningful patterns in household faunal assemblages. This finding demonstrates the importance of incorporating density-mediated destruction analyses in evaluations of taxonomic abundance measures. For the assemblage as a whole, I discovered significant fluctuations in the relative abundances of three leporid species (Nuttall’s cottontail, desert cottontail, and jackrabbits) and mountain sheep that appear to be related to climate change at the end of the Fremont Period. Strontium isotope data demonstrated that new sources of mountain sheep were used when environmental conditions became unfavorable to local populations. I also documented that later hunters at Five Finger Ridge were traveling to more distant locations to acquire large game using body part abundances and strontium isotopes.

This research attempts to expand the ways that archaeofaunal data are used for understanding prehistoric foraging decisions within a social context, while pushing methodological limits by extending the use of skeletal attrition and strontium isotope analyses. This research also provides significant data for understanding of the biogeography of a number of mammals and their responses to climate change in the past and present.