This is off the top of my head rather than checking but there should be a door to the monkey cave from the boar cave, and maybe a couple of others. The connections between the caves actually foreshadow connections between the characters. It’s a little difficult to tell because of how crowded the walls in each cave are, but if there’s an image of an animal that *isn’t* the one that the room is associated with, the door closest to it should lead to that animal’s room. Doors that lead to the monkey room won’t have any markings like that, or suspiciously thick moss growing where that mark would likely have been.