Behavioral Flexibility in the Sanje Mangabey (Cercocebus sanjei), Udzungwa Mountains, Tanzania




Lloyd, Emily Kathryn

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Understanding primate behavioral responses to fluctuations in resource abundance and distribution is a major goal of primate ecology. This dissertation research examines how the Sanje mangabey, an endemic primate species in an extremely diverse, tropical montane environment, responds to spatiotemporal resource variation. A combination of observational techniques were used to collect primate behavioral data, including diet, activity, substrate use, habitat use, and social and feeding data. Resource availability in the habitat was assessed using established phenology plots and vegetation transecting. Daily ranging data were collected using GPS locators. It is evident from this research that the Sanje mangabey is capable of significant foraging, social and feeding flexibility, enabling the maintenance of high levels of preferred food intake throughout the year. The mangabeys demonstrated strategic range shifting and selective exploitation of different habitats, and the utilization of a wide variety of food resources, especially through the use of cheek pouches to process large seeds out of ripe fruit pulp. Such flexibility permits the use of alternative within-group spatial positioning to mitigate potential within-group contest competition, demonstrating that the selective value of social dominance may be lessened in highly flexible primates within highly diverse environments. Overall, this study provides evidence that critical evaluations of socioecological models are enhanced by an examination of how multiple interacting variables influence primate behavior; such important refinements are required if these models are to continue to influence and reflect primatological theory.


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behavioral flexibility, cheek pouches, habitat shift, intraspecific feeding competition, seasonality, spatial organization