SPOILER ALERT the smart monkeys in the monkey pound escape, there must be say 30-50 of them? They then bust some regular ones out of the zoo (another 20-30?) as well as busting some more out of the research labs (100?), then they all escape into the forest via a bridge, and get lucky that it is a bit cloudy and the humans cannot see them to kill them. A few get killed along the way, then I guess the remaining procreate in the forest or something, then take over the planet. I suppose the humans could just nuke the forest or something, but maybe the monkeys would outsmart them again I dunno.