What the Dog Saw: And Other Adventures

day cycle? It was, in the words of its inventor, meant to fit into a case “indistinguishable” from a woman’s cosmetics compact, so that it might be carried “without giving a visual clue as to matters which are of no concern to others.” Today, the Pill is still often sold in dial packs and taken in twenty-eight-day cycles. It remains, in other words, a drug shaped by the dictates of the Catholic Church – by John Rock’s desire to make this new method of birth control seem as natural as possible. This was John Rock’s error. He was consumed by the idea of the natural. But what he thought was natural wasn’t so natural after all, and the Pill he ushered into the world turned out to be something other than what he thought it was. In John Rock’s mind the dictates of religion and the principles of science got mixed up, and only now are we beginning to untangle them.

2.

In 1986, a young scientist named Beverly Strassmann traveled to Africa to live with the Dogon tribe of Mali. Her research site was the village of Sangui in the Sahel, about 120 miles south of Timbuktu. The Sahel is thorn savannah, green in the rainy season and semi-arid the rest of the year. The Dogon grow millet, sorghum, and onions, raise livestock, and live in adobe houses on the Bandiagara escarpment. They use no contraception. Many of them have held on to their ancestral customs and religious beliefs. Dogon farmers, in many respects, live much as people of that region have lived since antiquity. Strassmann wanted to construct a precise reproductive profile of the women in the tribe, in order to understand what female biology might have been like in the millennia that preceded the modern age. In a way, Strassmann was trying to answer the same question about female biology that John Rock and the Catholic Church had struggled with in the early sixties: what is natural? Only, her sense of natural was not theological but evolutionary. In the era during which natural selection established the basic patterns of human biology – the natural history of our species – how often did women have children? How often did they menstruate? When did they reach puberty and menopause? What impact did breast- feeding have on ovulation? These questions had been studied before, but never so thoroughly that anthropologists felt they knew the answers with any certainty.

Strassmann, who teaches at the University of Michigan at Ann Arbor, is a slender, soft-spoken woman with red hair, and she recalls her time in Mali with a certain wry humor. The house she stayed in while in Sangui had been used as a shelter for sheep before she came and was turned into a pigsty after she left. A small brown snake lived in her latrine, and would curl up in a camouflaged coil on the seat she sat on while bathing. The villagers, she says, were of two minds: was it a deadly snake – Kere me jongolo, literally, “My bite cannot be healed” – or a harmless mouse snake? (It turned out to be the latter.) Once, one of her neighbors and best friends in the tribe roasted her a rat as a special treat. “I told him that white people aren’t allowed to eat rat because rat is our totem,” Strassmann says. “I can still see it. Bloated and charred. Stretched by its paws. Whiskers singed. To say nothing of the tail.” Strassmann meant to live in Sangui for eighteen months, but her experiences there were so profound and exhilarating that she stayed for two and a half years. “I felt incredibly privileged,” she says. “I just couldn’t tear myself away.”

Part of Strassmann’s work focused on the Dogon’s practice of segregating menstruating women in special huts on the fringes of the village. In Sangui, there were two menstrual huts – dark, cramped, one-room adobe structures, with boards for beds. Each accommodated three women, and when the rooms were full, latecomers were forced to stay outside on the rocks. “It’s not a place where people kick back and enjoy themselves,” Strassmann says. “It’s simply a nighttime hangout. They get there at dusk, and get up early in the morning and draw their water.” Strassmann took urine samples from the women using the hut, to confirm that they were menstruating. Then she made a list of all the women in the village, and for her entire time in Mali – 736 consecutive nights – she kept track of everyone who visited the hut. Among the Dogon, she found a woman on average has her first period at the age of sixteen and gives birth eight or nine times. From menarche, the onset of menstruation, to the age of twenty, she averages seven periods a year. Over the next decade and a half, from the age of twenty to the age of thirty-four, she spends so much time either pregnant or breast-feeding (which, among the Dogon, suppresses ovulation for an average of twenty months) that she averages only slightly more than one period per year. Then, from the age of thirty-five until menopause, at around fifty, as her fertility rapidly declines, she averages four menses a year. All told, Dogon women menstruate about a hundred times in their lives. (Those who survive early childhood typically live into their seventh or eighth decade.) By contrast, the average for contemporary Western women is somewhere between three hundred and fifty and four hundred times.

Strassmann’s office is in the basement of a converted stable next to the Natural History Museum on the University of Michigan campus. Behind her desk is a row of battered filing cabinets, and as she was talking, she turned and pulled out a series of yellowed charts. Each page listed, on the left, the first names and identification numbers of the Sangui women. Across the top was a time line, broken into thirty-day blocks. Every menses of every woman was marked with an X. In the village, Strassmann explained, there were two women who were sterile, and, because they couldn’t get pregnant, they were regulars at the menstrual hut. She flipped through the pages until she found them. “Look, she had twenty-nine menses over two years, and the other had twenty-three.” Next to each of their names was a solid line of x’s. “Here’s a woman approaching menopause,” Strassmann went on, running her finger down the page. “She’s cycling but is a little bit erratic. Here’s another woman of prime childbearing age. Two periods. Then pregnant. I never saw her again at the menstrual hut. This woman here didn’t go to the menstrual hut for twenty months after giving birth, because she was breast-feeding. Two periods. Got pregnant. Then she miscarried, had a few periods, then got pregnant again. This woman had three menses in the study period.” There weren’t a lot of x’s on Strassmann’s sheets. Most of the boxes were blank. She flipped back through her sheets to the two anomalous women who were menstruating every month. “If this were a menstrual chart of undergraduates here at the University of Michigan, all the rows would be like this.”

Strassmann does not claim that her statistics apply to every preindustrial society. But she believes – and other anthropological work backs her up – that the number of lifetime menses isn’t greatly affected by differences in diet or climate or method of subsistence (foraging versus agriculture, say). The more significant factors, Strassmann says, are things like the prevalence of wet-nursing or sterility. But overall she believes that the basic pattern of late menarche, many pregnancies, and long menstrual-free stretches caused by intensive breast-feeding was virtually universal up until the “demographic transition” of a hundred years ago from high to low fertility. In other words, what we think of as normal – frequent menses – is in evolutionary terms abnormal. “It’s a pity that gynecologists think that women have to menstruate every month,” Strassmann went on. “They just don’t understand the real biology of menstruation.”

To Strassmann and others in the field of evolutionary medicine, this shift from a hundred to four hundred lifetime menses is enormously significant. It means that women’s bodies are being subjected to changes and stresses that they were not necessarily designed by evolution to handle. In a brilliant and provocative book, Is Menstruation Obsolete?, Drs. Elsimar Coutinho and Sheldon S. Segal, two of the world’s most prominent contraceptive researchers, argue that this recent move to what they call “incessant ovulation” has become a serious problem for women’s health. It doesn’t mean that women are always better off the less they menstruate. There are times – particularly in the context of certain medical conditions – when women ought to be concerned if they aren’t menstruating: In obese women, a failure to menstruate can signal an increased risk of uterine cancer. In female athletes, a failure to menstruate can signal an increased risk of osteoporosis. But for most women, Coutinho and Segal say, incessant ovulation serves no purpose except to increase the occurence of abdominal pain, mood shifts, migraines, endometriosis, fibroids, and anemia – the last of which, they point out, is “one of the most serious health problems in the world.”

Most serious of all is the greatly increased risk of some cancers. Cancer, after all, occurs because as cells divide and reproduce they sometimes make mistakes that cripple the cells’ defenses against runaway growth. That’s one of the reasons that our risk of cancer generally increases as we age: our cells have more time to make mistakes. But this also means that any change promoting cell division has the potential to increase cancer risk, and ovulation appears to be one of those changes. Whenever a woman ovulates, an egg literally bursts through the walls of her ovaries. To heal that puncture, the cells of the ovary wall have to divide and reproduce. Every time a woman gets pregnant and bears a child, her lifetime risk of ovarian cancer drops 10 percent. Why? Possibly because, between nine months of pregnancy and the suppression of ovulation associated with breast-feeding, she stops ovulating for twelve months – and saves her ovarian walls from twelve bouts of cell