Imagine this situation: A genetics laboratory somewhere in the near future finds a way to bring extinct human ancestors back to life. The scientists can create as many specimen as they will, the revived species will be healthy, we know exactly what to feed them etc.. The question is: When is an animal too human to be kept in a zoo? Most people (though not all) will agree that top-quality zoos should be allowed to keep and breed currently living apes (chimpanzees, gorillas, orangutans etc.) for conservation purposes. But what if human ancestors were ressurrected? What if they can walk bipedally? What if they use complex tools? What if they can control fire? What if they have a human-like language, or human-like intelligence? Where do we draw the limit? Do we draw the limit at Australopithecus, which would probably resemble a bipedal chimp intelligence-wise? Or do we draw the limit at Homo erectus, which used tools but not fire and didn't have a fully developed language? Or Neanderthals, which probably had almost human intelligence, yet may have had behavior that differed from modern day humans? What do you think?