After World War II, the brutality of apes had become an anthropological preoccupation that promised answers to the question:
Does our capacity for depravity divide us from the animal kingdom, or does violence lie at the core of our nature, an upshot of our evolution?
Such unease only intensified as the brinkmanship of nuclear powers threatened to tilt into even more catastrophic conflict.
Against this backdrop, a corrosive vision of primate life grew more vivid: Front and center was a portrait of male tyranny, aggression, antagonism.
Fuel for this conviction can be traced back to the 1920s and the notorious carnage at Monkey Hill, a captive-primate colony at the London Zoo.
The Monkey Hill enclosure had been designed with the latest thinking on animal welfare in mind.
Rather than consigning apes to stuffy, shadowy cages where lung diseases ran rife, the open-air attraction featured artificial-rock monoliths furnished with heat and light.
To this impressive diorama, the zoo sought to introduce an equally impressive animal.
Amid a popular craze for all things Egyptian (King Tut’s tomb had lately been discovered), it settled on the hamadryas baboon, a creature that appears in hieroglyphics and, rendered as a deity, on pharaonic jewelry.
With the benefit of hindsight, as de Waal tells it, the exhibit was doomed from the get-go.
In their natural habitats in countries such as Somalia and Ethiopia, hamadryas baboons form polygynous groups.
Marauding, virile males snatch juvenile females from their kin before they become reproductively mature and amass “harems.”
But the zoo wanted only resplendent males, which can weigh nearly twice as much as females and sport a frost-gray ruff around a narrow, pumice-pink face.
About 100 were ordered.
When the baboons arrived, the staff found that the batch included a handful of surplus females.
On release, a bloody furor unfolded.
The males grievously injured or killed one another; they butchered or maimed more than half the females, and some copulated with corpses.
The event would be retold over the years as an archetypal narrative of male supremacy and barbarity and abject female subservience.
This, some were quick to pronounce, was what the animal within us looked like: We’re naturally led to dominate and oppress, or to be oppressed.