Carnivore Modification in North America: Perspectives on Neotaphonomy, Carnivore Use of Carrion, and Great Plains Bison Bonbeds

This dissertation addresses the use of carnivore modification studies in North America. Research in Africa has long been a dominant influence in zooarchaeological and taphonomic studies of carnivore modifications. The main question of interest driving the Old World research is timing of hominin access to large-mammal carcasses. In contrast, North American taphonomists' interest in the potential meaning of carnivore modifications focuses on site formation processes in faunal assemblages created by humans, such as mass-kills of bison. The research presented here has three objectives intended to broaden the goals of New World taphonomy. The first objective is to present a comparative analysis of carnivore utilization data from eight bison bonebeds in the northern Great Plains, which illustrate how important patterns in the data are detectable and reflective of significant changes in human-carnivore interactions. The second objective is to describe how measurements of carnivore utilization serve as an explanatory tool to help clarify past interactions of secondary scavengers and hunting predators (human groups) in Great Plains prehistory. The third objective is to provide detailed observational data concerning feeding behaviors of North American carnivores The methods and concepts developed in this dissertation are applicable to further studies of large-mammal mass bonesites elsewhere in the world by illustrating how to collect and analyze carnivore modification and utilization data in a manner useful for addressing paleoecological questions in any context. The first objective was reached through a program of data collection from curated bison-kill faunal assemblages. Temporal distinctions in the intensity of carnivore utilization appear in different cultural periods of Plains prehistory. Paleoindian and Late Plains Archaic sites exhibit the most modification and heaviest utilization. These temporal patterns appear to follow fluctuations of human population growth. The second objective was reached by developing a Scavenging Ecocenter model, in which carnivores are either conditioned to become dependent upon human-produced carrion, or respond to competition for prey resources by changing their intensity of carrion utilization. This model can be used to guide questions concerning the potential for carnivores to have been stressed by a reduction in ungulate biomass, due to prehistoric human hunters in the Plains frequently killing large bison herds. The third objective was reached by carrying out actualistic studies on different carnivore taxa, which are here shown to behave differently while feeding on large-mammal body parts. Captive North American wolves, coyotes, mountain lions, bobcats, grizzly bears, and black bears were fed defleshed hind limbs of cattle (Bos taurus) and lamb (Ovis aries). Wolves displayed behaviors that include use of incisors for pulling soft tissue, and use of cheek teeth for gnawing at bones and soft tissue. Coyotes displayed similar behaviors to wolves although they left few tooth marks. Mountain lions and bobcats crouched while feeding and caused the most structural damage to the bones, by scoring and puncturing proximal and distal portions of the femora. Bear-modified elements displayed furrowing and gouging to the proximal ends and those regions around the knee that contain soft tissue. Knowledge of the distinct feeding actions can aid in distinguishing the carnivore taxa responsible for certain bone modifications and their intensity of use in prehistoric assemblages. The above studies are linked together with the goal to expand the research undertaken and interpretive utility of carnivore modification studies in North America; first, to gain a more comprehensive appreciation of site formation processes; second, to build a knowledge base concerning how humans and scavengers interacted in the past; and third, to apply taphonomic knowledge to conservation and wildlife efforts of North American carnivores