Macaques, orangutans, and colobines all eat at the same fruit tree but there really isn't much fighting that goes on between them. Although, because the orangutans are much bigger than the macaques and colobines they eat more thus reducing the resource for the others. If the fruit trees are wiped out then the competition between these competitors will rise and they might start to become fierce with each other.
Orangutans need some loving too, right? An example of intraspecific competition between orangutans is finding a mate. Orangutans are much like humans because a preganancy lasts roughly nine months. They also only have one child at a time and only have one about every seven years because they have to take care of their offspring the first seven years of it's life. It is because they reproduce this slowly that finding a mate for the males is a serious job. Females are also very picky about who they want to mate with so alot of times the male that has the biggest cheek flaps win. If there is a sub-adult male trying to mate with an adult female, a larger, older male orangutan will come in and shoo away the smaller males. So, if there is a disaster that comes along, such as a tsunami, because they reproduce so slowly it could take decades for the population to go back to its normal size.