Sex at Dawn

Hrdy’s “seeds of confusion” theory posits that concealed ovulation and constant receptivity would benefit a female who had multiple male partners—by preventing them from killing her offspring and inducing them to defend or otherwise aid her children. Hrdy’s vision of human sexual evolution puts females directly at odds with males, who would presumably view fertile females as “individually recognizable and potentially defensible resource packets” too valuable to share.

Either way, as depicted in the standard narrative, human sexual prehistory was characterized by deceit, disappointment, and despair. According to this view, both males and females are, by nature, liars, whores, and cheats. At our most basic levels, we’re told, heterosexual men and women have evolved to trick one another while selfishly pursuing zero-sum, mutually antagonistic genetic agendas—even though this demands the betrayal of the people we claim to love most sincerely.

Original sin indeed.

*

But who would argue the gourmand takes less pleasure in her food than the glutton?

_*

We examine the nature of sexual j’ealousy in more detail in Chapter 9.

CHAPTER FOUR The Ape in the Mirror

Why should our nastiness be the baggage of an apish past and our kindness uniquely human? Why should we not seek continuity with other animals for our ‘noble’ traits as well?

STEPHEN JAY GOULD

‘Tis from the resemblance of the external actions of animals to those we ourselves perform, that we judge their internal likewise to resemble ours; and the same principle of reasoning, carry’d one step farther, will make us conclude that since our internal actions resemble each other, the causes, from which they are deriv’d, must also be resembling. When any hypothesis, therefore, is advanc’d to explain a mental operation, which is common to men and beasts, we must apply the same hypothesis to both.

DAVID HUME, A Treatise of Human Nature (1739-1740)

Genetically, the chimps and bonobos at the zoo are far closer to you and the other paying customers than they are to the gorillas, orangutans, monkeys, or anything else in a cage. Our DNA differs from that of chimps and bonobos by roughly 1.6 percent, making us closer to them than a dog is to a fox, a white-handed gibbon to a white-cheeked crested gibbon, an Indian elephant to an African elephant or, for any bird-watchers who may be tuning in, a red-eyed vireo to a white-eyed vireo.

The ancestral line leading to chimps and bonobos splits off from that leading to humans just five to six million years ago (though interbreeding probably continued for a million or so years after the split), with the chimp and bonobo lines separating somewhere between 3 million and 860,000 years ago.¹ Beyond these two close cousins, the familial distances to other primates grow much larger: the gorilla peeled away from the common line around nine million years ago, orangutans 16 million, and gibbons, the only monogamous ape, took an early exit about 22 million years ago. DNA evidence indicates that the last common ancestor for apes and monkeys lived about 30 million years ago. If you picture this relative genetic distance from humans geographically, with a mile representing about 100,000 years since we last shared a common ancestor, it might look something like this:

• Homo sapiens sapiens: New York, New York.

• Chimps and bonobos are practically neighbors, living within thirty miles of each other in Bridgeport, Connecticut, and York-town Heights, New York. Both just fifty miles from New York, they are well within commuting distance of humanity.

• Gorillas are enjoying cheese-steaks in Philadelphia, Pennsylvania.

• Orangutans are in Baltimore, Maryland, doing whatever it is people do in Baltimore.

• Gibbons are busily legislating monogamy in Washington, D.C.

• Old-world monkeys (baboons, macaques) are down around Roanoke, Virginia.

Carl Linnaeus, the first to make the taxonomic distinction between humans and chimps (in the mid-18th century), came to wish he hadn’t. This division (Pan and Homo) is now regarded as being without scientific justification, and many biologists advocate reclassifying humans, chimps, and bonobos together to reflect our striking similarities.