A growing concern in Southeast Asian countries is the interface between long-tailed macaques (Macaca fascicularis) and human beings (Homo sapiens) and the consequences that this sympatric relationship brings to the affected human communities and macaque populations. A variety of potential negative and positive consequences exist in zones of interface for both humans and macaques. As a result, the relationship between M. fascicularis and humanity has become a recent focus for academics and NGOs worldwide. In addition, regional governments, whose citizens have expressed concern about the disturbances caused by living closely with macaques, have attempted or are newly initiating programs to manage or reduce populations of macaques living alongside people. The occurrence of human–macaque overlap is not isolated to a few exceptional locations, but rather macaque synanthropy is a widespread phenomenon existing in regions all throughout peninsular and insular Southeast Asia. In this volume, we begin to build a more comprehensive understanding of long-tailed macaque populations and the extent of their overlap with humans.

In several regions of Southeast Asia, governments and NGOs have already initiated management programs to control macaque populations. These programs are a result of an effort to respond to citizen complaints and have set out to reduce what they consider overpopulated and/or nuisance macaque populations. Management programs have occurred or are occurring in Thailand, Malaysia, Hong Kong and Singapore, and to a lesser extent in some regions of Indonesia.