Monkeys (I am referring to Macaca fascicularis mostly)are every where in Malaysia. They are no more confined to the forests like may be twenty to thirty years ago.
Now many of them are near human dwellings, be it in the city, urban and peri-urban areas.
Because of many human sympathizers (are they really?) they could now find easy access to food, mostly human food - either from garbage sites or even being fed by their human neighbours.
The abundance of food makes them very prolific breeeders. Their number in an area easily double in no time.
If before (after their area is replaced by human dwellings) they are squatters in human land, but now they think that they are the masters.
They raid houses for food and there are also cases they raid just for fun and to satisfy their curiosity.
In many places they now become public nuisance. They have become an issue worth said even in the state action committee, these monkeys.
Ways to overcome? Not too many. One of them is to translocate them to another forest area. Sound so easy.
Having so used to easy life, these translocated monkeys do not do that well in their new area. They soon migrate to areas near human. They soon become a problem, even to the orang asli!