Diana,
my feeling about the gorillas at Animal Kingdom is that:
1. they have a great environment and appear to be enjoying it
2. so many people from all over the world get to see them and realize that they are endangered and, hopefully, will want to help them.

The Disney folks discussed with us how they maintain a database of every gorilla in captivity all over the world and the bloodlines of each of them so when they breed, they can find the best matches for overall health and longevity. They want these animals to survive. They are working to make it happen. A lot of the anti-zoo folks talk a good game but don't ever actually do anything to preserve the species. Philosophy without appropriate action is just a lot of hot air IMHO.

I've been to the Miami Zoo, Atlanta, Louisville -- some of the finest zoos in the world. As a photographer, I value the opportunity to see these guys and capture images of them.

Jim