Social Behavior in Adult Female Pigtail Macaques ( Macaca nemestrina ): Evidence for Familiarity‐Independent Pairing Success

ABSTRACT

This study examined how partner familiarity influences social behavior in pigtail macaques (Macaca nemestrina) housed in continuous full‐contact pairs. Behavioral data were collected from 40 novel and familiar adult female pairs across six observation sessions, three conducted in person and three via remote video, over a 10‐day period. A 100% success rate was achieved for all pairings. Overall, female pigtail macaques demonstrated strong social flexibility, showing few behavioral differences between familiar and unfamiliar partners. Novel pairs exhibited more mounting, move‐away behaviors, and affiliative facial expressions, which declined over time, indicating rapid social adjustment. While certain affiliative and submissive behaviors were sensitive to familiarity, the majority of social interactions remained stable and tolerant. Methods of observation had minimal impact on most behaviors, though facial expressions and approach behaviors were more frequently observed during in‐person sessions. These findings highlight the social competence and tolerance of adult female pigtail macaques and support their suitability for continuous pair housing with unfamiliar partners.