Robert Ardrey (b. October 16, 1908, Chicago, Illinois—d. January 14, 1980, South Africa) was an American playwright and screenwriter who returned to his academic training in anthropology and the behavioral sciences in the 1950s.
African Genesis and The Territorial Imperative, two of Robert Ardrey's most widely read works, as well as Desmond Morris' The Naked Ape (1967), were key elements in the public discourse of the 1960s which challenged earlier anthropological assumptions. Ardrey's ideas notably influenced Arthur C. Clarke and Stanley Kubrick in the development of 2001: A Space Odyssey, as well as Sam Peckinpah, to whom Strother Martin gave copies of two of Ardrey's books. Hammond Innes' novel “Levkas Man” (1971) was also influenced by Ardrey's views on the Stone Age roots of human aggression.
As a science writer for the informed non-specialist reader in paleoanthropology, which encompasses anthropology, ethology, paleontology and human evolution, Robert Ardrey was among the proponents of the hunting hypothesis and the killer ape theory.
Ardrey postulated that precursors of Australopithecus survived millions of years of drought in the Miocene and Pliocene epochs, as the savannah spread and the forests shrank, by adapting the hunting ways of carnivorous species. Changes in survival techniques and social organisation gradually differentiated pre-humans from other primates. Concomitant changes in diet potentiated unique developments in the human brain.
The killer ape theory posits that aggression, a vital factor in hunting prey for food, was a fundamental characteristic which distinguished prehuman ancestors from other primates.