For part of my degree I have to design an enclosure which could house Goodfellow's tree kangaroos. After doing some research on enclosures found in other zoos throughout the world I am particularly keen on the enclosure at both the Taronga Zoo and the Detroit Zoo. However, in all the photos/diagrams I have seen of outdoor enclosures I haven't noticed any walls in particular or a 'ceiling' so to speak. I would have thought this would be necessary because they can jump from so high and could potentially jump out of a tree and escape? Maybe I'm being silly... Any info anyone has would be an incredible help!