Publication Date


Document Type


First Advisor

Porter, Leila M.

Degree Name

M.A. (Master of Arts)

Legacy Department

Department of Anthropology


Central American spider monkey--Effect of predation on--Costa Rica; Predation (Biology)--Costa Rica; Parental behavior in animals--Costa Rica


Predation risk is a significant survival problem for immature primates, but only a few studies have examined the risk of predation on immatures in ateline primates. This study examined whether spider monkey mothers changed their interactions with their infants due to a perceived change in predation risk while foraging in different sized groups. I proposed that a mother's proximity to her infant/juvenile varied depending on whether she was alone with her offspring, with one other adult female, or with a larger group of adults. Because group living potentially reduces predation risk, I suggested that mothers would be in closer proximity to their infants when there were no other adults present. I also predicted that mothers would be in closer proximity to their infants than to their juveniles since infants are likely to face greater predation risk than juveniles. However, the differences in mother-offspring distances between infants as compared to juveniles were smaller than predicted and there was little to no evidence that a mother's distance to her infant was driven by group size. My prediction that a mother's proximity to other adult group members has an effect on her vigilance behavior was also not supported. These results suggest that feeding competition rather than predation risks may be the primary factor in determining mother-infant distances in spider monkeys.


Advisors: Leila Porter.||Committee members: Dan Gebo; Laurie Kauffman.||Includes bibliographical references.||Includes illustrations.


iii, 39 pages




Northern Illinois University

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