in the wild things ain't so easy. death rates are higher, males fight, lose females, lose groups and yes, fly solo.
however, even batchelor gorillas have interaction with other gorillas, even if it may on occasions be negative. and whilst they may have a somewhat lonelier life, its a free and enriched one.
one of my biggest issues i must keep reiterating is not just that rigo was kept alone, but that he was kept alone in that exhibit. the humane thing to do would have been to give the silverback gorilla access to the rainforest exhibit.
of course he wasn't, because one gorilla on display isn't as good for the visitors as a eight.
a good compromise would have been two groups of 4 or 5, but then that would not have avoided the issue of fixing the grottoes, which would house one group whilst the other was on display in the bigger enclosure.
the orangutans also lived in these appalling exhibits for too long, however, for the most part, they had eachother as stimulus. something rigo would have had if he was managed in an ethical manner.