Interpreting Pleistocene Predator-Prey Dynamics: Inference from Skeletal Pathology, Dental Growth and Stature
- Author(s): Brown, Caitlin Anna-Corbett
- Advisor(s): Van Valkenburgh, Blaire
- et al.
Mammalian teeth and bone contain a record of an animal’s health and environment over daily, weekly, and yearly time scales. These tissues have long been used to assess the health and environmental conditions particular to individuals, but they may also preserve characteristics of entire populations, in this case relative population size and behavior. In this dissertation, we draw new inferences from skeletal and dental characters to demonstrate that they preserve 1) unique signals of predatory behavior and 2) relative changes in ungulate population size. Chapter 1 assesses the potential of skeletal pathology to preserve a signal of behavior in extinct species, specifically the hunting modes of two Pleistocene predators reconstructed as ambush and pursuit predators, respectively. To answer this question we analyzed injury rates across thousands of pathological elements and performed quantitative analysis of injury locations, the first such application of spatial analyses. In chapter 2, we documented a correlation between population size, nutritional status and dental/osteological features in extant moose (Alces alces) using mandibles collected over the past five decades from Isle Royale, MI. This is the first attempt to use patterns of dental growth and wear in past or present populations to infer food-limitation and relative density. In chapter 3 we examined incremental growth rates of dentin, the tooth tissue surrounding the pulp cavity, allowing a first look at the responses of tooth enamel, dentin and bone growth to episodes of stress in a wild population. Through this work we developed methods of characterizing past ecosystems to benefit studies that seek to restore national parks to their pre-anthropogenic state or contribute to the long-standing paleontological debate regarding the Pleistocene mammal extinctions. As a result of our efforts, we have a robust set of both macroscopic and microscopic indicators of predatory behavior (Chapter 1) and nutritional stress (Chapter 2-3) that can be applied to extinct and extant carnivoran and ungulate and populations.