In the 70s, my family had a squirrel monkey for about seven years. The monkey was a great pet. Yes, we housed it in a cage, but we had an outside summer cage when it got warmer. We took it out of the cage on a leash. It was fed a monkey chow with additions of healthy human food. He gave his life in the end, but saved ours. Like a canary in the mines, he died from car fumes that would have caused our death. I agree with mainbutter that no ape should be kept by a normal family. I believe that there are species that can be kept, providing the owner is willing to learn the needs of the animal.