Afinando o tom: um estudo vocal longitudinal em Callithrix jacchus juvenis selvagens

Abstract

The white-tufted marmoset (Callithrix jacchus) is a species of neotropical primate native to northeastern of Brazil, inhabiting the Caatinga and Atlantic Forest regions. They have many biological and social characteristics similar to humans, including a cooperative breeding system and gregarious habits, combined with a broad vocal repertoire. In addition to being targets of interest in biomedical research due to their similar biology and for being easy to keep in captivity, the vocalizations of these animals have been extensively studied recently, with increasing evidence of learning mechanisms and vocal plasticity. However, few studies evaluate the natural context in which they occur in the species, with most of them focusing on the infancy and adulthood phase of these animals. Our research investigated acoustic parameters variations of four types of vocalizations in juvenile marmosets (5-10 months) over a six-month period in a natural environment: “phee”, “cry”, “twitter” and “trill”. We then compared these variations with those of adult marmosets (from 15 months of age), seeking to understand the vocal development of young marmosets and social context in which calls are used. We did not observe significant variations in acoustic parameters of the analyzed vocalizations in juvenile marmosets throughout the study, nor any noticeable influences of vocal feedback for young individuals. However, we did observe differences in frequency values of “cry” and “phee” between juveniles and adults, with a tendency for juvenile averages to approach those of the adults. Our data also confirms the presence of vocalizations from infant to the adult phase in marmosets and shows variations in usage frequency and context for all vocalizations. As indicated by previous authors, these subtle and gradual variations in acoustic parameters and in vocalizations usage in juvenile marmosets suggest that, despite a vocal profile that can be largely explained by biological development, social experiences must be important for maturation and contextualization of the main vocalizations of marmosets.