Capture from the wild
All macaque species are vulnerable to human exploitation, the synanthropic species (those who have adapted best - and even might thrive - on the fringes of human areas) probably most of all. When populations are perceived to be too large, or conflict with humans is present, they are sometimes rounded up and sold, live or dead, as subjects for biomedical experimentation.
Human residents in one Malaysian neighborhood, who had assumed that they were simply being relocated, were alarmed to learn that the pig-tailed macaques trapped in their area were being killed, and in such large numbers that a second incinerator had to be built to accommodate. In this case, the authorities carrying out this work were so under-resourced that they were unable to check the traps on a regular basis and many macaques died in their trapping cages in the interim.
Macaques may be hunted for food, or captured intentionally or opportunistically to be pets or performers. In Vietnam, a large proportion of macaques surrendered to government-run rescue facilities show evidence of snare wounds, suggesting that they were caught in snares set for other animals and then kept or sold.
Apart from the immediate physical and psychological distress of being trapped, snared or otherwise captured, such activities severely disrupt macaque social hierarchies and connections between individuals, compromising the well-being of not only those individuals who have been taken, but also of those left behind.