Birth control in urban macaques: Description of a tubectomy program and post-op monitoring in Macaca fascicularis, Indonesia

In Asia, primates and humans are increasingly forced to share space, and often enter in conflict when primates proliferate in anthropogenic environments. Reproductive control is increasingly used to limit population growth but very few monitoring data are available. Therefore, the efficiency and implications of such programs require a careful examination. Our research aims to assess the adequacy and implications of a three-year sterilization program in wild female long-tailed macaques in Ubud, Bali. We present the rationales behind the selected methods (surgical approach of endoscopic tubectomy and giant trapping cages for captures) and we describe the demographic population model used to establish the objectives of population growth control. We then present the outcomes of this program and the postoperative monitoring results. 137 females underwent tubectomy over four successive campaigns between 2017 and 2019, which represented 45% of the sexually mature females of the population. The survival rate was very high (96%) six months after sterilization and no major postoperative complication were recorded. No novel pregnancy in treated females was observed, reflecting a 100% success rate of the procedure. Moreover, the surgical approach was also applicable for pregnant females since 26% of the treated females were pregnant at the time of the surgery and 77% of them experienced term delivery. Overall, this study case demonstrates the safety and efficiency of tubectomy sterilization as mean of population control in wild macaques. A demographical and behavioural monitoring is currently in progress to provide a global evaluation of the implications of such programs