Maybe Snowleopard or another American chatter can elaborate on the situation in the US. How many actual 'working' bachelor groups have you got these days?
@ Pertinax: There are 25 bachelor troops in 20 zoos.
As is the case now with AZA elephant husbandry standards. How do we get them to do the same for gorillas. It was AZA who changed this?
@zooman: The AZA has complied some kind of husbandry and facilites guidelines for nearly every taxa or major species.
There are currently 15 solitary gorilla males in US zoos. 6 of these males are soon to be integrated into a social grouping.