Just questions- WHy is it necessary to have "survivor" kill or be killed as the premise in these types (there have been several) of stories? Isn't it possible that rather than into more warlike chimpanzee clans humans could rather de-evolve to more supportive/caring bonono-like families? What a lack of imagination on the part of the writers who turned this out as a horror story. What does it's popularity say about the state of our world today?