The grunt and girney vocalizations of free -ranging female rhesus macaques

• Main Author: Whitham, Jessica Camille Ring
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01.01.2007
• Subjects: Physical anthropology; Psychobiology; Zoology
• ISBN: 9798209539131

I investigated the grunt and girney vocalizations of female rhesus macaques (Macaca mulatta) to assess whether these calls are best interpreted as representational signals of benign intent (Silk et al. 2000), signals that operate through other mechanisms, or arousal-related calls with no communicative function. I focally observed 19 free-ranging adult female rhesus macaques on the island of Cayo Santiago before and after the beginning of the birth season. Female calls increased dramatically after infants were born in the study group and most were directed at mother-infant dyads. When infants were physically separated from their mothers, callers visually oriented towards infants in the majority of cases, suggesting that infants were the recipients of vocalizations. Females were more likely to groom mothers, less likely to elicit a submissive response from mothers, and more likely to initiate infant handling if they called after they approached than if they remained silent. Infant handling, however, was not necessarily benign. Females often emitted vocalizations from a distance > 1 m and approaches or social interactions with mothers or infants rarely followed calls. Rather, the female simply sat and observed the infant, sometimes tail-wagging while vocalizing. My results are consistent with the hypothesis that grunts and girneys are arousal-related, attention-getting or arousal-inducing vocalizations with which female monkeys address young infants. Mothers, however, may have learned that grunts and girneys are unlikely to be associated with significant risk and therefore, are generally tolerant of the caller's proximity and behavior.