Sucking: A Love Story
From the moment my son was born, the one and only thing he asked of the world was that it give him something to suck. Among the very first photos I took of him, there’s a shot that foretells the next half year of his life. His pink-gray hand, wrinkled and fuzzy, takes up almost all the foreground. It’s expertly splayed with tension, as if he’d practiced jazz hands in the womb. In the background, slightly out of focus, is his mouth, agape, bobbing for boobie.
He’s missing. He has horrible aim.
It’s Isaiah’s first photo starring him and his new best friend. It is also the beginning of an obsession, his desperate need to get something—anything—into his mouth and suck on it like a toothless vampire bat.
He was designed to be a vampire bat: a newborn is a body led around by a mouth. It is his most sensitive organ, his most useful tool for probing the mysteries of the world—the best way to probe any mystery being to suck on it, of course. When you have a hammer, everything looks like a nail; when you are a baby, everything looks like something to suck. Even nothing is something to suck. Watch a sleeping or sleepy infant closely and you will often see her mouth slowly, silently, suck on nothing but air.
The typical baby in the parenting books we were reading seemed to be highly discriminating about what she sucked. The parents have tried every bottle; they’ve bought every brand of pacifier. But the baby accepts no substitutes for the breast. The baby will not be fooled. There’s an undercurrent of pride to these stories. Our child is too clever for these tricks, they seem to say. It is difficult having such a smart, loving, prodigiously attached child. But we manage.
This is not what Isaiah was like. He sucked—poorly—on his thumbs and fingers, and—expertly—on dirty laundry, stuffed sheep, our necks, other people’s noses. He not only accepted substitutes to the breast; he preferred substitutes. If we had put lumber in his bassinet, he would have sucked it down to driftwood.
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Over the years, a lot of people have not dealt well with finding a vampire bat in the nursery.
For more than a century, the sight of a baby sucking—how we have understood it, rationalized it, recoiled from it—has had a weird capacity to inspire and magnify parental anxieties. This is true for sucking in all its manifestations: breast-feeding and wet nursing, thumb-sucking and pacifiers, each of which has its own peculiar and revealing history. Each has left a mark: our continued confusion and ambivalence about pacifiers, and even thumb-sucking, is the legacy of these forgotten battles.
They were fierce, moral battles. Even before Sigmund Freud, a spurious association between sucking and sexuality had planted itself in the minds of parents and doctors. A treatise on childhood diseases from the turn of the century is matter-of-fact about it: “Infants who persist in the habit of sucking always become masturbators.” What were these infants sucking? Their thumbs. Such habits in infancy were said to be the seeds of adult delinquency. Mothers who ignored them were woefully naïve: “Even when warned and fully understanding the dangers, they in mistaken kindness, for temporary present good, neglect to provide against certain future evil.”
A hundred years later, too much sucking is still distressing. Even Google is aware of our unease: if you type “pacifiers” into the search engine, the first suggestion offered is “pacifiers good or bad.”
Babies, of course, have always picked good. “The immediate pleasure value of his mouth activity to the infant himself is easy to see from his reaction,” the psychiatrist Margaret Ribble wrote a half century ago in The Rights of Infants, the rare book at the time to acknowledge how vital sucking was for babies. “Pleasure is the principle on which he accepts or rejects; at this stage it is his criterion of good and bad, and no Emily Post is going to make him pretend anything different.” Those who have looked closely have always been amazed by the deep pleasure and meaning that babies find in sucking. Even Charles Darwin took note of it. “It may be presumed,” he wrote with dry affection of his newborn son, William Erasmus Darwin, “that infants feel pleasure whilst sucking and the expression of their swimming eyes seems to show that this is the case.” Freud, famously, compared the rapture of sucking—those swimming eyes—to orgasm. I thought Isaiah looked more like he’d slipped under the spell of a powerful opiate, as if he were taking in breast milk derived from a strict diet of poppy-seed cake.
Sucking is the act that governs early infancy. For generations, this fact has been oddly terrifying. It shouldn’t be. We know now that sucking is a benevolent dictator: it means well. If anything, it is supremely ironic that sucking has been the subject of so much grief. It’s how newborn babies survive. It’s almost the only thing they can do. You’d think we’d be happy they were so good at it.
When other mammals arrive in the world, they take advantage of the fact. Shortly after being born, a calf can stand. A deer can run.
A baby can suck.
There are no mammals who arrive in the world to lower expectations than the human newborn. After marsupials, which are suckled in a pouch until they can cross the street, we are the least prepared, least advanced mammals at birth. The amount of time we need before we are truly ready for post-utero life is much closer to eighteen months than to nine. It takes human infants nine months outside the womb before they are as capable as a chimpanzee in its first minute of life.
This ineptitude is evolution’s blessing and its curse, and to understand why such an arrangement would ever make sense, we have to rewind the tape a couple of million years. The brains of our newly upright ancestors were exploding in size, but the birth canal was shrinking: the new bipedal lifestyle required a narrower pelvis. It was, essentially, “a conflict between walking and thinking.”
Bigger heads, smaller openings: no one needed a traffic report to see the bottleneck. “The professions of obstetrics and midwifery probably would not exist,” as the anthropologist Wenda Trevathan observes, “were it not for the inherent conflict between the bipedal pelvis and the large-brained infant.” There was an imperfect compromise: mothers began to give birth sooner, when the fetus was relatively small-brained. It was the only way to reconcile a big brain with a small pelvis: the bulk of the brain growth—the bulk of what was supposed to happen during gestation—now took place outside the womb, where there were no physical barriers. It was a highly atypical arrangement: the brains of most mammals grow quickly only before birth. The brains of humans quadruple in size after birth.
All this meant that gestation, counting the time spent inside the womb and the time outside it, now took approximately forever. There are other mammals that gestate at our achingly slow pace. And there are other mammals that are born helpless. But Homo sapiens is the only mammal that’s both: we take forever to prepare ourselves and we’re still not ready in time.
This paradox is responsible for the extraordinary achievements of the species later in life: among our many questionable singular virtues, it is why we are the only mammal to go to graduate school. But to any mother exhausted after hours of labor, what may be more apparent is how little evolution has willed her at that moment: a mammal—possibly a baby, possibly a naked mole rat—who will not smile at her for well over a month but who will scream from the instant of birth.
He can do almost nothing else. Except suck.
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When Carl Linnaeus, the great Swedish naturalist, sorted the natural world into taxonomical categories for his magnum opus Systema Naturae—the foundation for how we think and talk about all plants and animals—he threw out the Quadrupedia class, which ordered warm-blooded animals by their number of feet, in favor of an order determined by mammae, or breasts. Hence, Mammalia, or mammals. Early taxonomical classification was an art, not a science, and not always physiologically rigorous: a previous influential scheme had divided animals between the biblical categories of clean and unclean. Mammalia was a more scientific classification, but it was still somewhat arbitrary. There are at least a half-dozen characteristics unique to all mammals, including hair. But not all mammals have mammae: male horses, for example, as Linnaeus himself admitted, have no breasts.
Linnaeus, as the historian Londa Schiebinger has argued, might have been wiser to move away from form and toward function: rather than focusing—scandalously—on the physiological fact of breasts, he should have directed the eyes of naturalists to what those mammae are designed to do. This distinction makes so much sense it already exists. In German, mammals aren’t named for what they have; they’re named for what they do. They are Säugetiere—suckling animals. If Linnaeus had made this tweak, we would think of ourselves today not as Mammalia but as Sugentia: the suckling ones. Sucking is our true mammalian obligation. More than any anatomical fact, it is what connects us to our fellow mammals.
Proof of the nomenclature is in the womb: as Sugentia, we give ourselves prenatal hickies. Like children covered with cookie crumbs, newborn babies inadvertently disclose what they have been up to out of sight. They emerge from the womb with their bodies tattooed by compulsive sucking. You can see fetuses contentedly sucking on their extremities on ultrasounds. Infants born without sucking marks on their hands or arms may have already found their thumbs and fingers, which is why a newborn, a creature incapable of holding her head up, is able to find her hands shortly after birth. It’s not luck. It’s practice. Fetuses are able to move their hands up to their face by the end of the first trimester; by sixteen weeks, they begin sucking their thumbs.
In-utero sucking prepares the fetus for the critical task of nursing. So does swallowing. By the end of gestation, the fetus swallows as much as a liter of amniotic fluid every day just to keep the composition of the uterine environment from falling out of whack. It’s proportionally more liquid, compared to body mass, than any of us will ever drink again.
Since taste buds emerge as early as the first trimester, we all once knew what the womb tastes like. Fetuses are highly sensitive to taste: experiments conducted decades ago, before the advent of ethical niceties, found that a fetus will swallow more amniotic fluid after the injection of saccharin and less after the introduction of a “noxious” substance. Amniotic fluid has many of the same flavors as breast milk, and newborns may find a measure of comfort in nursing because it makes their new alien world seem a little more like home. They uniformly prefer any odors or flavors they experienced in the womb; they turn toward their mother’s amniotic fluid and away from that of another mother. The connection between amniotic fluid and breast milk is the rare bit of continuity from the prenatal to the postnatal world—think of breast milk as the very first transitional object.
As adults, we look at newborns, these befuddled arrivals in our ex-utero world, and we naturally see versions of us—really lousy versions of us. But it may be more fair to see newborns as really good versions of Sugentia. They are designed to do what they have to do: their facial muscles, astonishingly well developed, flush milk out of their mothers; their guts thrive on the milk; their teeth arrive tardily, for their mother’s sake.
They are born ready to suck. You might think that after the trauma of birth—the physical stress, the astonishment of arriving in a new world—a baby might need some time to get himself together. But the readiness of a newborn to suck, measured by sucking pressure, is at its maximum just after birth. Within six to eight hours afterward, it has already declined.
A newborn is so ready, in fact, that if placed on his mother’s chest after birth he will find his way to her breasts on his own. It will take him almost an hour, he will have been guided almost exclusively by his nose, but he will make it. It’s an extraordinary act of blind will. Newborns are comically nearsighted—approximately 20/400—but their sense of smell is fully developed and they suss out their surroundings with it. At a week, breast-fed babies identify their mother by smell: in experiments, they consistently turn their heads toward her breast pad and away from the pad of another lactating mother. (A week later, they identify their mother’s armpit odor.) When newborns are placed on their mother’s chest between a washed and an unwashed breast, they consistently choose the unwashed breast—the side with her scent.
On the spectrum of postpartum nursing competence, we are closer to rats, who can’t nurse if they can’t smell, than farm animals like sheep and cattle, who can wobble their way, eyes open, to the nipple. Precisely what we do when we get there had long been a mystery. Only twenty-five years ago, a paper on the anatomy of sucking began by saying, “It is clear from recent lay and professional texts that there is much confusion as to the precise nature of infant sucking.”
There’s a good reason for this: it is genuinely confusing. What babies do is not what the word “sucking” leads you to expect: babies pump out milk not so much by sucking as by squeezing. The infant squeezes the breast between his tongue and palate, elongating the nipple and compressing it with wavelike motions of his tongue; this expresses the milk, which is then swept away for swallowing. Suction doesn’t actually propel the milk from the breast; it just keeps the nipple in place. (Our idea of how breast-feeding works—an infant sucking milk out of the breast—is actually how bottle-feeding works.)
Scientists have now studied breast-feeding in millisecond-level detail. With mathematical rigor, researchers have tried to calculate norms for swallow rates, suck runs, efficiencies of feeding, rhythmic stability—every aspect of a suck or swallow. Having hyperdetailed data enables earlier diagnoses of neurological or feeding disorders in high-risk infants. And feeding disorders are common: feeding is complicated. In order to nurse successfully, a newborn has to coordinate sucking and swallowing with breathing: a few milliseconds off in any direction and the whole apparatus malfunctions. If a baby breathes in milk, he chokes; if he swallows air, he gets gas. Eating is a remarkable achievement, the most complex motor act a newborn can accomplish. In approximately a tenth of a second, a litany of crucial openings and flaps are covered, raised, lowered, squeezed—all to prevent liquid from dripping into the lungs. Things can go wrong at any point in this process, for almost any reason. It is a physiological marvel that all infants don’t have pneumonia from sodden lungs.
This is what’s happening behind a baby’s chugging cheeks. We notice almost none of it. We can’t notice it. Sucking is a high-wire balancing act performed only behind a curtain. It’s a marvel that fails to seem marvelous.
Copyright © 2013 by Nicholas Day