This large gorilla habitat has no apparent barriers towards the back of the exhibit. I've visited the Woodland Park Zoo countless times, and yet I have no proof of where the enclosure actually ends. There is a moat somewhere hidden beneath all of the lush foliage, and this is the larger of the two enclosures. There are about a dozen gorillas at the zoo, divided into two separate troops, and there have been at least a dozen births since the zoo opened these natural environments in 1979.
This is one of the best gorilla exhibits in North America, because it has a large canopy with a bed of hay in one area, an expansive lawn towards the right of the exhibit, and plenty of foliage and lush, non-hotwired areas for the apes to hide. It is not a cage by any means and it is not an empty soccer field like many other great ape enclosures, but simply a combination of the two. There are rocks and a small waterfall, and I have no idea how far back the habitat extends. Incidentally, it is 30 years old this year!
@snowleopard Quite remarkable and noteworthy how progressive / ahead of its time this kind of enclosure was when it was opened in 1979 and I'm sure that even to this day it suits the inhabitants very well.