Age-related changes and vocal convergence in titi monkey duet pulses

• Published in: Behaviour Vol. 156; no. 15; pp. 1471 - 1494
• Main Authors: Clink, Dena J, Lau, Allison R, Bales, Karen L
• Format: Journal Article
• Language: English
• Published: Leiden|Boston Brill 2019; Brill Academic Publishers, Inc
• Subjects: Age; Conspecifics; Convergence; Monkeys; Plecturocebus cupreus; Primates; Pulse duration; Pulse rate; Regular articles
• DOI: 10.1163/1568539X-00003575
• ISSN: 0005-7959

Abstract Duets in pair-bonding primates serve as a primary mode of communication between pairs, and duets may provide cues to conspecifics regarding the calling individual or pair. Here, we test the hypothesis that pulse elements in coppery titi monkey duets vary with condition and identity of the caller. We predicted that pulse elements would vary with age, sex, or pair-bond length. We estimated pulse rate and duration for 378 pulse elements from the duets of 74 captive titi monkeys (Plecturocebus cupreus). We found inter-individual variation in both features, and evidence for vocal convergence among pair mates in pulse rate. Age was the best predictor of pulse rate, and pulse rate decreased with age. Age and pair-bond length reliably predicted pulse duration. Our results suggest that variation in titi monkey duets reflects differences in caller condition and pair identity, and contribute to growing evidence for vocal plasticity in nonhuman primates.