Student Prize Award Abstract
2002 Poster Paper Award

SOCIAL CONTEXT AFFECTS VOCAL STRUCTURE IN A CALLITRICHID PRIMATE (CALLITHRIX KUHLII)

M. Rukstalis; J. E. Fite and J. A. French
UNOmaha, Callitrichid Research Center, Department of Biology, University of Nebraska at Omaha, Omaha, NE, 68182, USA

The degree to which changes in social environment affect the vocal structure of non-human primates is a topic which has remained largely unexplored. To date only one other study, in pygmy marmosets, has specifically investigated the flexibility of the vocal behavior of callitrichid primates in response to novel conspecifics (Elowson and Snowdon, 1994). We assessed the cross-species generality of this finding in Wied's black tufted-ear marmosets (Callithrix kuhlii). Individual phee calls were obtained over a period of nine weeks from animals housed in five pre-existing social groups. All calls were then analyzed for several acoustic and temporal features including call duration, bandwidth, and peak frequency. Four of the five groups were then placed in auditory contact with an unfamiliar group and recorded for an additional nine weeks. Given that C. kuhlii and C. pygmaea are closely related species with similar social systems, reproductive strategies, and ecologies we predicted that natural selection should also favor the ability of C. kuhlii marmosets to modify the structure of their "phee call" (contact call) in response to the presence of novel conspecifics. Our results suggest that marmosets maintain vocal plasticity beyond early developmental stages and social environment plays a larger role in vocal structure then previously demonstrated.