it's a decent size (with the siamang there for scale), but not exactly a lot of brachiating room. They're basically going to be going round in circles.
When they get worked up they'll most likely do a bit of to-and-fro-ing, then up and down, then throw themselves from one of the top ropes down to catch a lower rope, swing around a pole, etc.
I think, considering the size of the exhibit, anymore brachiating space and the animals may be able to leave the exhibit.
