A Stepwise Male Introduction Procedure to Prevent Inbreeding in Naturalistic Macaque Breeding Groups

SIMPLE SUMMARY: Housing of primates in groups increases animal welfare; however, this requires management to prevent inbreeding. To this end, males are introduced into captive macaque breeding groups, mimicking the natural migration patterns of these primates. However, such male introductions can be risky and unsuccessful. The procedure developed by the Biomedical Primate Research Centre (BPRC), Rijswijk, the Netherlands, to introduce male rhesus macaques (Macaca mulatta) into naturalistic social groups without a breeding male achieves relatively high success rates. Males are stepwise familiarized with and introduced to their new group, while all interactions between the new male and the resident females are closely monitored. Monitoring the behaviour of the resident females and their new male during all stages of the introduction provides crucial information as to whether or not it is safe to proceed. Flow diagrams identify which decisions must be made during the introduction period. The BPRC introduction procedure is widely applicable to primates with natural male migration. Following this procedure may improve the management of captive primate groups in any housing facility worldwide. Altogether, careful introduction management can minimize the risk associated with male introductions and enhance the welfare of captive primates. ABSTRACT: Male introductions into captive primate breeding groups can be risky and unsuccessful. However, they are necessary to prevent inbreeding in naturalistic breeding groups. The procedure used to introduce new individuals may affect the success and influence the risks associated with group introductions. At the Biomedical Primate Research Centre (BPRC) in Rijswijk, the Netherlands, male rhesus macaque (Macaca mulatta) introductions into naturalistic social groups with a matrilineal structure and without a breeding male achieve relatively high success rates. This paper describes the male introduction procedure used at the BPRC. Males are stepwise familiarized with and introduced to their new group, while all interactions between the new male and the resident females are closely monitored. Monitoring the behaviour of the resident females and their new male during all stages of the introduction provides crucial information as to whether or not it is safe to proceed. The BPRC introduction procedure is widely applicable and may improve the management of captive primate groups in any housing facility worldwide. Thus, the careful introduction management can minimize the risk associated with male introductions and enhance the welfare of captive primates.