Date of Thesis

Spring 2018


Self-directed behavior, such as self-scratching and self-grooming, is a behavioral indicator of anxiety in nonhuman primates. Patterns of self-directed behavior are used to identify social and environmental factors related to primate anxiety. This study explored the social context in which individuals in a captive group of hamadryas baboons (Papio hamadryas hamadryas) exhibited self-directed behavior. Self-directed behavior in a partner’s presence was predicted to increase with relationship insecurity. More than 130 hours of behavioral observations were conducted on 12 baboons. Self-directed and social behavior were recorded with focal sampling to determine each animal’s self-directed behavior rate in the presence of each other group member. These data were also used to calculate variation in response to approach over time, a newly proposed measure of relationship insecurity. Aggressive and submissive behavior were recorded ad libitum to construct a dominance hierarchy. High-ranking animals were found to exhibit significantly higher rates of self-directed behavior than low-ranking animals. Adults also exhibited higher rates of self-directed behavior than juveniles. Self-directed behavior rate increased with the relative dominance rank of the social partner in close proximity. Self-directed behavior rate also increased with the overall amount of aggression the social partner exhibited over the course of the study. No relationship was found between self-directed behavior rate in a partner’s presence and relationship insecurity. Results suggest that baboons in this group experienced anxiety related to their own dominance rank and that of their social partners. Captivity and the steeply linear nature of the group’s dominance hierarchy may have prevented any possible relationship insecurity effects from emerging. Variation in response to approach over time did not positively correlate with other relationship variables, suggesting it may serve as an independent and viable measure of relationship security.


primate behavior, self-directed behavior, social behavior, anxiety, hamadryas baboons (Papio hamadryas hamadryas)

Access Type

Masters Thesis

Degree Type

Master of Science


Animal Behavior

First Advisor

Peter G. Judge