Who you calling an animal? (Human nature, part II)

Human beings are animals.  Our extraterrestrial observer might at first find little reason to assume that our human species is very different from the many other species populating our planet.  This non-human observer might have access to samples of terrestrial DNA, which would indicate to the observer that homo sapiens is closely related to other varieties of primate, a little more distantly to the many more species that bear and nurse live pups, and yet more distantly to all of the other living (as well as extinct) species on the planet.  But the DNA would clearly indicate that homo sapiens shares common biological origins with the rest.  Yet this observer would soon discover compelling indications that homo sapiens is somewhat unique among terrestrial species—the capacity of our species to build massive cities and orbital structures, dominate terrestrial resources, capture and enslave other species, and transform the entire planetary environment for our short-term use.  This observer might be impressed (or not) with our literature, our culture, our technology, our politics or the quality of our abstract thoughts, but could hardly fail to observe our collective ability to dominate our world, even to destruction.  This observer might also note that we seem inordinately boastful about this very capacity.

We human beings have various and conflicting attitudes toward the other indigenous species of our home world.  We exploit, incarcerate and destroy non-human species with deliberate and coordinated precision.  (We may also have done this with closely-related but now-extinct human species.)  We breed, raise and modify other species for personal display and consumption.  But we also treat them as members of our families, sometimes stooping to pick up their waste as if we were their devoted servants.  And we often attribute humanlike motives and personalities to these pets.  Perhaps we think we do them the complement of making them more like ourselves.  But we might turn the comparison around, consider that we are finding ourselves to be very much like them.

Many of our human behaviours are embarrassingly indistinguishable from animal behaviors.  You’re not sure?  Spend a bit of time observing how a typical human being occupies her day.  Like her cat, she will pass the greater part breathing, sleeping, blinking, stretching, yawning, scratching, eating, drinking, belching, defecating, and attending to the myriad physical needs she shares with other species of animal.  Are our yawns qualitatively different from cat yawns?  Is our sleep meaningfully distinct from a dog’s sleep?  Most of our behaviors fall beneath the level of conscious planning, as with other species.  Our genomes and protein-making functions are largely indistinguishable from those of other species—no doubt because we are so closely related to them.  There are really only a few behaviors and abilities in which we differ from other animal species, and perhaps then only in degrees.  But you may be resisting this conclusion.  An animal is, by definition, something other than a human being.  Whose definition is that?  Ours, of course.  It favors our desire for exceptionalism.  But we are hardly unbiased word-spinners.  (And cats resent being lumped together with those barbarous dogs.)

Think about sex.  (Perhaps you were already.)  How would you go about explaining human sexuality in entirely dispassionate and rational terms to an intelligent extraterrestrial that happened to reproduce asexually.  Explain the reasoning process by which you selected your present sexual preferences.  Oh yes, you were concerned about the precarious numbers of your species, so made a rational decision to commit yourself to a form of reproductive activity that you would otherwise have shown little interest in.  Since reproduction is your singular goal, personal attraction is of no concern whatever.  Sex is merely a clinical procedure to achieve a specific end—a viable offspring.  (Indeed, this is how millions of teenaged boys first developed their purely practical concern for sex.)  And if we were capable of choosing our sexual behavior on such terms, sex as we practice it now (with all the wasteful dating and dinners and extravagant displays of affection) would be entirely transformed.  We would be indifferent to the method of producing offspring as long as it got the job done.  Society would celebrate every human pregnancy equally.  Birth control would be unheard of.  But the more uncomfortable truth is that we possess these aggressive sexual desires precisely because nature has such little confidence in our reasoning abilities.  The pleasures of sex are really a series of electrochemical processes, the human versions not so far removed from those driving animal reproduction.

Still not convinced that you’re an animal?  Think of a televised crime drama in which the plot turns on the discovery of a crucial piece of DNA evidence.  The victim is discovered to have skin cells beneath her fingernails, presumably from the last person with whom she had physical contact before her violent demise.  The state’s expert witness reveals with conclusive-looking DNA slides that the victim and the perpetrator were closely related.  Even the defense attorney’s own expert witness can do no better than suggest that the sample might have come from any one of four other people, all closely related to the victim (and all with airtight alibis).  The jury brings in a guilty verdict because it finds the prosecutor’s case compelling—so does the television audience.  We all know that individual members of the human species are each just a little bit different from the others, even when they belong to the same ethnicities or birth families.  Most of us (even casual television viewers) accept that modern genetics can show whether two individuals are closely or distantly related.  We accept this because each individual genome is constructed by the intermingling of their parents’ genomes (“you’ve got your mother’s eyes, but your father’s temper”), just as their genomes had been similarly inherited from their parents.  The genome of every individual is unique (barring identical twins) but varies according to well-established and easily-mappable rules.  We are most closely related to those with who we share recent ancestors (parents and grandparents), more distantly to those with whom we share distant ancestors.  How far back?  As far as you can go.  There are no clear boundaries, no obvious stopping places.  Every human being on earth is related to every other human being (within approximately 2400-3000 generations—that’s a lot of third-plus cousins).  But by the same genetic rules we are also related, a little more distantly, to every other hominin species that has lived on the planet in the last several hundred thousand years (all extinct but for us, though we retain some Neanderthal DNA), and just a little more distantly to every other species of primate.  We have most of our genome in common with chimpanzees, bonobos and gorillas.  We can keep going—to the remainder of the mammalian class, then to birds and reptiles and the rest of the animal kingdom, then to virtually every other living being all the way to the origins of terrestrial life.  Almost all living beings on the planet share not only a fundamental genetic structure but the same cellular interloper—mitochondrial DNA—which passes exclusively from mothers to offspring.  We share this trait with virtually all other species on our planet.  It’s really no more likely that all these different species were distinct and separate creations than that you and your second cousins were.  We’re all related here.  As far as genetics is concerned, the borders between species are of little significance, especially when considered in the context of time.

The natural evolution of our species is nothing other than reproductive genetics (as dramatized in the crime program) multiplied over generations.  Just as there are small differences between individuals of the same breeding population (which is all that a species is), so there are slightly greater differences between recently-diverged species.  We can call some of these differences mutations, as long as we understand that mutations (those giving rise to heritable variations) are among the ordinary mechanisms of sexual reproduction.  The more adaptable genetic combinations (that is, those useful for prospering and propagating within the specific environment at hand) are more likely than others to be reproduced.  This is natural selection’s irreducible measure of success.  Human beings (homo sapiens) have survived and expanded both in numbers and across diverse territories over the past few hundred thousand years (but for a close call some 60,000 years ago) because we have adapted more successfully than others to our various environments—not compared to other living species, but to those that did not survive and reproduce.  We humans have proven to be a very successful animal species, though it may be too soon to call.  Our self-awareness may be a key part of our winning adaptation “strategy” (though no one thought of it before it happened), but we are otherwise no different from any other species that has survived in its environment and produced offspring.

To remain honest with ourselves and with the other members of our species with whom we interact to manage our shared society, we would do best to remember that we are stuffed with animal needs and animal drives.  We may reluctantly have to sympathize with young males (or even older ones) who have difficulty controlling their aggressive behavior and sexual impulses.  They did not choose those drives.  It is their natural behavior, and may at times be overwhelming.  It cannot be wished away.  Yet to succeed in a civil society—a very deliberate and artificial construct—they (and we) must strive to better manage these animal behaviors.

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And human beings are primates.  We can learn a lot about our own behaviors as human beings by observing our nearest surviving relatives.  Our closest living non-human cousins are chimpanzees and bonobos, with whom we share more than 98% of our genome.  Chimps and bonobos are closely related to one another yet distinguished by a slightly different African environment and about 900,000 years of evolution (whereas we are 6-7 million years removed).  Their behavior has evolved dramatically in the meantime.  Chimpanzees are more prone to aggression and violence, and have been documented taking part in gang warfare, murder and cannibalism.  (The chimps you see on kids’ television are not adult males—those would be much too aggressive and dangerous to work with.)  Bonobos have generally enjoyed a more abundant food supply and tend to live peaceably.  They prefer making love to war.  The two varieties between them exhibit much of the range of human behavior.

Compare the adult male of the human species to another of its nearest surviving genetic relations—the gorilla.  If you have watched a silverback interacting with other members of his social group (a popular exhibit at any major zoo), you will realize that the dominant male tends to be a bad-tempered, aggressive and rather selfish individual.  He will bully or destroy male rivals.  He will use female members of the band for his own pleasure.  He will take the first choice of available food—even seize it from others if they get to it before he does.  He rules by virtue of superior strength and aggressiveness (like Zeus over the Olympian gods).  But we don’t berate him for this behavior.  We consider it natural—beyond choosing or conscious control.  In the wild, his aggressive behavior may even be necessary for the protection and survival of his troop.  Likewise, adult male chimpanzees are often violent and unsympathetic individuals, capable of appalling brutality, bullying, even chimpicide.  Now consider how adult human males are inclined to behave when unconstrained—the ones we call alpha males.  Their aggressive and frequently destructive behavior has driven much of human history.  And for much of it the other members of society have chosen to placate them or stay out of their way.  Today we are more inclined to call their bad behavior what it is—uncivilized, boorish, out of date.  Yet this behavior is as much the manifestation of inherited genes as is the behavior of other great apes.

But we may also note that a silverback gorilla (at least in nature) is unlikely to enjoy a long, comfortable and prosperous old age.  There is no retirement for him, no pension earned from a lifetime of social superiority.  He can expect no gentle nursing care in his declining years.  Those who rely on brute force to maintain their superiority will likely end their lives in violence.  So it may well be for us—we can choose a long life with a comfortable retirement or gamble on social dominance, but probably not both.