The zoo used to have tree kangaroos, banded palm civets and a tiger quoll (it has since died) in the Aussie Road House, so I'm sure that one of those animals occupied this exhibit along with the echidna(s).
Yes, the climbing structures were for the Tiger Quolls (and Binturongs before the quolls). We were going to acquire more after ours had passed away but we decided to dedicate the space to our echidna. This picture also doesn't show the floor of the exhibit which provides about one foot of dirt for the echidna as well as some shrubs and logs.
Please take the trash container awy from there, if anybody from the institution is reding this.This is a rather special exhibit.If you were to visit the Prado museum, you would not find a trash can right in front of the "Las Meninas" painting.I realize zoo visitors can be messy, but I am sure there are many other places perfect for the trash can.