MaRGA Meeting, 2004: Abstracts

13: Neuroscience / Communication / Behavior

Preliminary Evidence of Early Long Call Acquisition
and Usage in a Callitrichid Primate (Callithrix kuhlii)

M. Rukstalis¹ and J.A. French²

Affiliation: Callitrichid Primate Research Center, ¹Departments of Biology and ²Psychology, University of Nebraska at Omaha, Omaha, NE

The acquisition and appropriate usage of adult vocalizations among infant primates is a topic which has generated much controversy. Recent research has suggested that primate infants may experience more complex periods of vocal ontogeny then previously believed. However, this study presents preliminary evidence of a limited ontogeny in the acquisition and appropriate usage of one vocalization, the long call, in Wied's black tufted-ear marmosets (Callithrix kuhlii). We assessed the morphology and usage of phee calls (i.e., long calls) in isolated marmoset infants from one to seven weeks of age. Infant marmosets removed from their natal cage vocalized frequently, participating in antiphonal calling bouts with parents and siblings. When compared to adults, the structure of marmoset infant long calls was similar even as early as eight days of age (mean duration of call 2.73s vs. 2.87s, respectively). While infant calls were similar, some structural differences were evident. In general eight day-old infant marmosets had higher maximum and minimum call frequencies then adults (11.98 kHz and 7.93 kHz vs. 7.99 kHz and 5.74 kHz respectively), used more syllables per call (5.2 vs. 3.7), and had shorter average syllable length (348.2 ms vs. 595.5 ms). These differences were reduced by seven weeks of age and may reflect maturational changes (i.e. increasing vocal tract length and body mass) rather than development of a functional call. While additional calls in the marmoset's repertoire may undergo more complex periods of development, the preliminary evidence presented here suggest that long calls may experience a limited ontogeny.