I haven't been up there for over ten years. I believe the mandrill might be off-exhibit (she is getting VERY old) and the gorillas like to hide. But I heard the drill boys are very curious and easy to see and of course the star of the exhibit is the chimps which, in their arboreal exhibit, are visible from all over the zoo.
They used to have it so it was 3 males gorillas, 2 mandrills, and a Diana Monkey. The last time I went I did see the female in exhibit. She was with the male gorillas. ISIS says there are two male drills, and one female mandrill. I am not sure where the Diana Monkey, and Mandrill went. They probably passed but I am not sure. The Diana monkey was bought at a pet store by a Brooklyn family in Florida. Cookie, the monkey was spayed and had here canines removed. She was given to the Detroit Zoo, and I guess was some how combined in with the other primates. You would think she would have had issues.
