Monkey Mountain was only separated from the large enclosure inhabited by the gibbons by a five or six-meter-wide circular path, making them genuine neighbors.
Monkey Mountain was recessed into the ground, so from within the gibbons' enclosure, one could easily take in the entire view of Monkey Mountain. Conversely, from Monkey Mountain, one could see into the gibbons' cage just as well. It could be said that every move of one party was under the watchful eye of the other.
Being primates themselves, the gibbons and the macaques of Monkey Mountain used to get along quite well and rarely fought. If the Monkey King was in a good mood, he would even throw some fruit towards the gibbons' enclosure from a distance. Their "languages" must have been mutually intelligible, as they sometimes chattered and hooted at each other across the circular path, holding conversations that no one else could understand.