Shadows of Forgotten Ancestors

Maybe our distinction is the traditional and striking gender-specific division of labor: The men hunt and fight; the women gather and nurture.²⁵ But this cannot be a defining characteristic, because chimps have a similar division of labor: Patrols, group defense, and throwing missiles are all mainly male responsibilities; caring for the young and using tools to crack open nuts are mainly female responsibilities. Also, women’s and men’s jobs are in our time becoming increasingly indistinguishable.

Our long childhood, the years between birth and puberty, is essential for our education, but it is not as long as an elephant’s; and the progressively earlier arrival of sexual maturity in the human life cycle over the last few centuries is whittling down our childhood so that it is now only a little longer than the chimpanzees’ (who sexually mature around age ten). Play is so central to our growing up that it was once suggested²⁶ to call our species Homo ludens

(“the man who plays”). But play can be seen throughout the mammalian class, especially when maturity is long delayed.

The Roman philosopher Epictetus, a former slave, held the distinguishing characteristic of humans to be personal hygiene.²⁷ He must have known about birds, cats, and wolves but argued that “when … we see any other animal cleaning itself, we are accustomed to speak of the act with surprise, and to add that the animal is acting like a man.” But he then complains that many men are “dirty,” “stinking,” and “foul” and do not share this “distinguishing” characteristic. Such a man is advised to “go into a desert … and smell yourself.”

Humans have been called the only animal that laughs. However, chimps smile and laugh a lot.²⁸ The Athenian Stranger, in Plato’s Laws,²⁹

says humans are “afflicted with the inclination to weep more than any other animal.” But this inclination varies widely from culture to culture, and whimpering and crying is a fact of daily life among the chimps, children and adults alike.³⁰

Humans—who enslave, castrate, experiment on, and fillet other animals—have had an understandable penchant for pretending that animals do not feel pain. On whether we should grant some modicum of rights to other animals, the philosopher Jeremy Bentham stressed that the question was not how smart they are, but how much torment they can feel. Darwin was haunted by this issue:In the agony of death a dog has been known to caress his master, and every one has heard of the dog suffering under vivisection, who licked the hand of the operator; this man, unless the operation was fully justified by an increase of our knowledge, or unless he had a heart of stone, must have felt remorse to the last hour of his life.³¹

From all criteria available to us—the recognizable agony in the cries of wounded animals, for example, including those who usually utter hardly a sound*—this question seems moot. The limbic system in the human brain, known to be responsible for much of the richness of our emotional life, is prominent throughout the mammals. The same drugs that alleviate suffering in humans mitigate the cries and other signs of pain in many other animals. It is unseemly of us, who often behave so unfeelingly toward other animals, to contend that only humans can suffer.

Murder, cannibalism, infanticide, territoriality, and guerilla warfare are not unique to humans, as described in preceding chapters. Ants have slaves and domesticated animals and main force warfare.

“The use of punishment in the attempt to train their young in anything other than avoidance,” writes Toshisada Nishida, “seems exclusively limited to humans … No nonprimate mammals are known to teach by discouragement.”³³

But his exception of the nonhuman primates says much. Also, many animals coerce and punish the young as part of the educational process, aiding smooth entrance into the dominance hierarchy. It’s a little like hazing and initiation rites in our species.

Humans have institutionalized marriage and advocated monogamy, at least as an ideal; but gibbons, wolves, and many species of birds practice monogamy and mate for life. The courtship dances of animals are surely a kind of marriage ceremony. The following characteristics are described as typical of human marriage:There is some degree of mutual obligation between wife and husband. There is a right of sexual access (often but not invariably exclusive). There is an expectation that the relationship will persist through pregnancy, lactation, and childrearing. And there is some sort of legitimization of the status of the couple’s children.³⁴

But all of this is known in other animals, for example among the gibbons, plus primogeniture.