On a recent episode of the Dear Hank and John podcast (in which two brothers give “dubious advice”, I recommend it!) a listener sent in a question about why human infants were so useless. And even though both of them have children of their own, they didn’t really know what the answer was so they gave it their best shot: (paraphrasing here) because of bipedalism, women’s hips are too narrow and the baby needs to come out prematurely otherwise they won’t fit.
If you’ve read the earlier parts in this series debunking the Obstetrical Dilemma, you can imagine my epic head shaking and eye-rolling. I had already had this post waiting in the wings but I decided to rework the intro and title when I realized that lay people who have never heard the phrase “obstetrical dilemma” will forward it without even being aware of it. So, why are newborn humans useless?
In western culture, there is a long tradition of women suffering through labor… something about an apple? Throughout the history of obstetrics, theories have been tossed about to explain humanity’s apparently unique difficulties in childbirth. One of the more recent is the Obstetrical Dilemma which posits that the female pelvis is too narrow to give birth to human babies (without a lot of professional, technical intervention, and even then… ) but too wide (wider, on average, than a male pelvis) to be efficient.
Racist Roots with a side of Misogyny
The OD hypothesis came into being around the same time that hospital birth was becoming the norm in the United States. In 1949, Aldoph H. Schultz, from the John Hopkins University School of Medicine in Baltimore, Maryland published a paper titled Sex Differences in the Pelves of Primates about the pelvic measurements of a variety male and female cadavers from a selection of primate species. Among these non-human primate species are chimpanzees, gorillas, and negroes.
Yes, you read that correctly. And if you aren’t horrified, I am not sure I want you reading my blog.
Schultz believed that black people represented a different species of primate, describing their pelvic measurements as more animalistic than whites, as a means of explaining why they had easier births. His research was used to justify the lack of medical care available to pregnant black women across the U.S. but even more so in the Jim Crow south. Continue reading
When a chimpanzee is born, they are able to grasp their mother’s fur with their hands and feet and cling on effectively within weeks. A human newborn is not as strong or directed in their efforts though they still retain some of the so-called primitive reflexes from our common primate ancestor which fade as a human baby gets older. Newborn humans can strongly grasp with their hands (palmar grasp reflex) and they can flex their toes (plantar reflex) but due to their foot morphology, which lacks an opposable hallux (a big toe that looks more like a thumb) they cannot grasp with their feet as they do with their hands.
This is a problem for a species of “riders“, mammals whose breastmilk composition requires them to carry their baby with them for frequent feedings, unlike “parkers” whose offspring can be left for long stretches while their mother hunts or forages (or goes to the bathroom by herself for crying out loud!) If a baby cannot cling to it’s unlikely to survive, most rider mothers cannot afford the extra energy (literally in the form of calories) to carry their infant and it would certainly slow her down in the face of danger. Even if the mother did everything in her power to carry and protect her baby, the odds are against their survival and so that babies trait, the trait for not being able to cling on, wouldn’t get passed on. Unless of course, the mother was clever enough to make a technological adaptation for easier carrying… (you see where I am going here). Continue reading