Date of Thesis

Summer 2021


Vocalizations are an important form of communication in brown capuchins. Vocal communication research in other species has suggested that vocalizations are acoustically individually distinctive, that subjects can distinguish identity based on these individualities, and that affiliative social bonds can influence a subject’s response to call playback, with more highly-affiliative individuals receiving more of a response. The present study involved a playback experiment where a single individual heard four in-group conspecifics, two high-affiliative and two low-affiliative, to determine whether brown capuchins distinguish conspecifics based on vocalization, and if the responses given are influenced by the strength of the affiliative social bond in the pairing. There were no differences in the behavioral responses of brown capuchins to the calls of high social affiliates over the calls of low social affiliates, but we explore multiple possible explanations for the suggestion that brown capuchins do not distinguish individual identity from hearing calls. The present study also found that subjects respond more to playbacks of alarm calls than to long calls, which reinforces the importance and complex dynamics of vocal communication in these primates.


brown capuchin, Cebus apella, Sapajus apella, vocal communication, social affiliation, playback

Access Type

Masters Thesis (Bucknell Access Only)

Degree Type

Master of Science


Animal Behavior

First Advisor

Dr. Reggie Gazes

Second Advisor

Dr. Peter Judge

Third Advisor

Dr. Aaron Mitchel

Available for download on Monday, July 22, 2024