Dissertation Research: Population Density, Social Behavior, and Physiological Stress in Lemur catta

Princeton University, Princeton NJ

Investigators

Abstract

Differences in population density are often reflected in social behavior yet the pathways and mechanisms remain to be elucidated, particularly in natural populations. This research on a wild population of the prosimian, Lemur catta, uses endocrine responses to identify the relative contributions of several ecological and social stressors to density-dependent changes in behavior, physiology, and reproductive success. The study benefits from unique field conditions in which six habituated primate groups are studied across a well-documented population-density gradient, and research methods have been established for obtaining individual-level data on survival, reproduction, foraging efficiency, aggressive behavior, and levels of stress response as measured by excreted steroids sampled without intervention. The data for approximately 80 animals over a two-year period permit testing the hypotheses that food scarcity, conflicts within groups, and conflicts between groups are reflected to varying degrees in cortisol levels and that the magnitude of this stress response predicts individual health and short-term reproductive success.