Watch Movies2Watch. A documentary based on Robert Ardrey's books that presents 15 million years of human evolution. The author believes that man began killing systematically 30,000 years ago when the Cro-Magnon Man killed off the Neanderthal Man because the latter was different. Man has been killing ever since. This very rare and most unusual docudrama with a cast made up entirely of men in ape suits is based on the work of the impossibly pompous anthropologist/ screenwriter Robert Ardrey, who attempts to unpack the origins and evolution of the killer instinct.