I've seen several shows on this monkey, and that's exactly wht Oliver is, a monkey. When he was taken on a tour of China, it was claimed that he had matching genetic make-up of both humans and chimps...
This was untrue, however. He is just a monkey. He was likely captured as a baby and trained to walk upright. He is also known for drinking beer and smoking cigars. All things that any chimp can be trained to not only do, but things they would likely enjoy anyway.