DescriptionBetween individual differences that show within individual stability have garnered increasing interest in animal behavioral ecology. Such research spans across a diversity of taxa using a variety of theoretical frameworks. One challenge of studying individual differences is determining which personality traits are biologically relevant and theoretically salient. The coping style and stress reactivity framework offer a compelling solution to this challenge by focusing on the biologically significant process of mounting a stress response, which is of relevance as the stress response often necessities rapid decision making under circumstances with a certain degree of uncertainty. Additional environmental information afforded by inhibition during a stress response can be invaluable in avoiding a stressor, or cost an organism its life through the time lost. Coping style and stress reactivity historically have been used in a variety of small-bodied taxa, but recent applications have applied this framework to captive primates or post hoc to wild primates. Utilizing this framework a priori with wild primates is significant because such individual differences in the stress response are theoretically salient for informing how individuals response to social stressors. Such differences in a wild primate could, therefore, scale-up to influence social structure.
I completed a 17-month field study on 44 wild adult olive baboons (Papio anubis) from two groups in Laikipia, Kenya. I utilized experiments to quantify coping styles and stress reactivity; personality surveys to measures personality trait differences; focal animal sampling to collect behavioral data for dominance hierarchies, social group structure, and behavioral tendencies; as well as fecal sampling to attain concentrations of fecal glucocorticoid metabolites. I begin this dissertation by outlining several of the alternative theoretical frameworks for understanding individual differences. Then I expand upon the utility of the coping style framework and why baboons have utility as study subjects under such a framework.
Chapter 2 of this dissertation details a unique experimental paradigm which simultaneously presents a threat with an incentive. This paradigm is used to obtain measures of individual differences in coping style and stress reactivity. Validation of the experimental results is conducted by examining my findings in light of those from a variety of other taxa. I compare these experimental results to behavioral rates from the focal follow data and find that, overall, the experimental data are poor predictors for behavioral rates. Similarly, survey-collected personality factors – Neuroticism, Assertiveness, and Friendliness – do not covary with the stress reactivity and coping style scores, with the exception of stress reactivity predicting Neuroticism.
Chapter 3 details whether the experimental results can be used to predict social network position or social dominance rank. The coping style scores were predictors neither for social network strength nor degree across several behavioral networks. Homophily, however, was observed for coping styles in a strong-edge proximity network, such that individuals that scored similarly in the coping style factor scores were more likely to have strong associations in a two-meter proximity network.
Chapter 4 examines whether coping style and stress reactivity scores interact with measures of social support and dominance certainty to predict fecal glucocorticoid metabolites concentrations. None of the variables of interest were strong predictors of fecal glucocorticoid metabolites, with the exception of social support. Males that had a greater number of strong grooming partners had lower fecal glucocorticoid metabolite concentrations than males with fewer weaker grooming partners.