Temperament and Social Hierarchy in a Colony of Juvenile Male Southern Pig-Tailed Macaques (Macaca nemestrina) at the Primate Research Center, IPB University

Abstract

The use of southern pig-tailed macaques (Macaca nemestrina) as animal models requires adherence to animal welfare principles and the 3Rs (replacement, reduction, and refinement). This study aimed to characterize the temperament of individual juvenile pig-tailed macaques and to determine the social hierarchy structure within a captive colony to support the development of appropriate management and training strategies. Temperament assesssment was conducted through behavioral observations using a standardized ethogram durig 20-minute focal samping sessions, four sessions per day over 14 consecutive days. The subjects were four juvenile males aged approximately three years housed in colony cage GM 2/4 at the Research Animal Faciity at Lodaya (RAF-L), Primate Research Center, IPB University. We recorded 2,838 behavioral events across five temperament categories (aggresive, neutral, affiliative, submissive, and anxious). A one-way ANOVA with Tukey HSD post hoc test  revealed that affiliative behaviors were significantly more frequent than othercategories (p<0.05). Three individuals exhibites predominantly affiliative temperaments, while one exhibited an aggresive temperament. Social hierarchy positions (high rank, middle rank, and low rank) were established by accumulating the frequency of aggressive-submissive interactions among the four individuals. One individual occupied the high-rank position, one occupied the middle rank, and two were categorized as low rank. notably, one low-rank individual that had been hand-reared displayed elevated frequenciea of anxious behaviors, including steretypic pacing. these findings provide a behavioral baseline for refining colony managemnet and training protocols consistent with the 3Rs framework.