Photo from early 80s. Apologies for its poor quality: scanned from a faded print, of a picture taken when I was very young.
This pit was part of the zoo development in the late 70s / early 80s. It wold have made rather a good coati or racoon enclosure, maybe, but was quite a snug fit for the three brown bears that resided there, and spent most of their time begging for nuts (as in this picture). They eventually escaped, and were shot - an event that contributed to the zoo's eventual closure, I think.