There is pest control. And the government will actually pay a bounty on dead monkeys. However, individuals can't own guns here (without going through a LOT of paperwork that is still not likely to be approved) so you can't just go out and shoot them. And the tourists love them, so you can't do anything obvious like setting traps, or you'll get tourist backlash. If they get too annoying or do something dangerous, you can call the official government monkey exterminator. But they are pretty adorable ... they often use our lawn as a place to let the babies play that is safely fenced. :-)