Why Do Women Have Breasts, Anyway?

Maybe because I’ve never had the sort of chest that men stare at, I’m more willing to consider alternative theories of origin. And there are lots. One thing making it tricky is that, unlike the opposable thumb, breasts leave no fossil record. There’s no way of knowing exactly when the well-endowed rack appeared in human evolution. Was it before bipedalism or after? Before we lost our fur? Pretty much all of the theories accounting for breasts, Mascia-Lees’s and the Dixsons’ included, are best categorized as SWAG, scientific wild-ass guesses.

Since breasts are catchments of our collective and individual fantasies, it makes sense that not even scientists are immune from their charms. When we consider the mysterious origin of this fine fleshy organ, breasts become easy metaphors for whatever we desire, from buttocks to political hegemony. One desert zoologist sees in breasts the camel’s hump, an adaptation that allows us to survive in arid climates through fluid and fat storage. To feminists, the breast story is a parable of self-determination.

There are plenty of other entertaining, if far-fetched breast-origin stories. Wrote Henri de Mondeville, the surgeon to King Philippe le Bel of France in the early fourteenth century, “The reasons why the breasts of women are on the chest, whereas other animals more often have them elsewhere, are of three kinds. First, the chest is a noble notable and chaste place and thus they can be decently shown. Secondly, warmed by the heart, they return their warmth to it so that this organ strengthens itself. The third reason applies only to big breasts which, by covering the chest, warm, cover, and strengthen the stomach.”

In 1840, one physician speculated that fatty breasts warm the milk and “enable women of the lower class to bear the very severe blows which they often receive in their drunken pugilistic contests.” He’d perhaps been reading a few too many Gothic novels.

More recently, an Israeli researcher posited that fatty breasts are needed to help the upright female maintain her balance. Otherwise, her fatty bottom would tip her backward. My sister-in-law says this is certainly the reason in her case.

Elaine Morgan, the Welsh critic, has buttressed her own breast theories with some astute anatomical observations. She notes that when our ancestors lost their fur, babies faced some new challenges. Other tiny primates cling to their mother’s fur from a very early age. Mom is free to swing from the trees and dig up ants, even while junior breast-feeds. No such luck for humans. We have to hold our little urchins, and the best place for that is the crook of our arm. Even then, though, the nipple still needs to come down a bit to baby. The pendulous breast came to the rescue. Then, once the human baby’s hands were free from clutching, they could gesture. An important form of expression evolved and helped make us who we are.

The whole enterprise is greatly assisted by a flexible, unmoored nipple. As Morgan puts it, the brilliantly shaped human breast “ensures that the nipple is no longer anchored tightly to the ribs, as they are in monkeys. The skin of the breast around the nipple becomes more loosely fitting to make it more manoeuvrable, leaving space beneath the looser skin to be occupied by glandular tissue and fat. Adult males find the resulting species-specific contours sexually stimulating, but the instigator and first beneficiary of the change was the baby.”

I can wholly affirm that it would be very awkward to breast-feed without a nice moveable feast of a nipple. British anthropologist Gillian Bentley of the University of Durham was nursing her own child when another anatomical light bulb went off: it was our skull shape that drove the ontogeny of rounded breasts. One of the major distinguishing features between us and other primates, indeed between us and most mammals, is our lack of anything resembling a snout. There could be a couple of reasons for this. One is that we have different jaw and teeth structures, the better for eating a varied diet, including cooked meats, which means we don’t need huge mandibles to rip apart raw flesh. Another is that we have humongous brains and, at birth, relatively large heads, five times the size of what you’d expect in a primate our size. But in order for newborns to get through our unusually narrow bipedal hips, their faces need to be flat, said Bentley. Flat faces and flat chests don’t work well together. Think of kissing a mirror; if the baby’s face had to smoosh against a flat chest, it wouldn’t be able to breathe through its nose. (Now here you might be clever and ask, as I did, Why didn’t evolution instead come up with a different place for the nose, say, near the ear? In fact, why are all mammal noses between the eyes and mouth? The answer has to do with our primitive, born-from-fish infrastructure, a template we’re not free to mess with. No doubt it was easier for our genes to tinker with the breast instead.) Thanks to round breasts, we can be smarter.

NEXT: “What if instead of men selecting breasts, the breasts selected the men?”

TAGS: breasts and natural and unnatural history | florence williams | why do women have breasts

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