The concept of the 'killer-ape' offers a pessimistic reflection of humanity and its genesis, but the latest research shows that a primate species whose success is based on mutual aid and pleasure, not violence, is a better model for human origins.
Eric Michael Johnson in Times Higher Education:
In 1607, after being held captive by the Portuguese in West Africa's Congo Basin for nearly 18 years, the English sailor Andrew Battell returned home with lurid tales of “ape monsters”. The larger of the two creatures Battell described, according to the edited volume later published by travel writer Samuel Purchas, Purchas His Pilgrimes, “is in all proportion like a man”, but “more like a giant in stature…and has a man's face, hollow-eyed, with long haire upon his browes”. These marauding beasts “goe many together, and kill many (villagers)…they are so strong, that ten men cannot hold one of them”. Battell's narrative, much of which was received second hand and sure to be highly imaginative, was nevertheless one of Western society's earliest introductions to our evolutionary cousins, the great apes.
Simia quam similis turpissima bestia nobis (“How similar the ape, this ugliest of beasts, is to ourselves”). What the Roman poet Ennius presented in the 2nd century BC was a refrain that could be heard repeatedly during the subsequent two millennia whenever Europeans encountered this being that so threatened the line separating human and animal. The common depiction of non-human primates in the West as representations of sin and the Devil, wickedness, frivolity, impulsivity and violence would ultimately say more about our own discomfort at being reminded of similar qualities in ourselves than their nature.
But it is the depiction of the ape as monster that is even more revealing.