I’m a bookcase snoop. When I am invited to a new home, I can’t wait to see what they have on their bookshelves or coffee table. A lot of people seem to enjoy when I post about what I am currently reading so I thought I might highlight a few of my favorites from my bookshelves. And I’d love to hear from you on your favorites. Continue reading
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
Anyone who has cared for a newborn as been there. That moment when you feel like you have tried everything to soothe your crying baby and you just want to sit down and cry yourself. But what if there was some magic trick that would calm your baby and brighten your own mood? According to science there just might be some magic in taking a walk with your baby– but you’ll need to carry them for the full benefit. 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
Humans, like the other Great Apes, are physiologically riders; breast milk composition is not suited to parking infants for long periods between feeding (Ross). For this reason among many others, our species has had to carry our babies with us wherever we go. Unfortunately, humans find carrying infants more difficult than our evolutionary cousins for three reasons: lack non-grasping feet and body hair, physically helpless infants and, most importantly for this post, the relative size of our infants.
Non-human apes in the taxonomic family Hominidae (literally means “Great Ape” and makes me think of Charlotte’s Web’s “Some Pig” but I digress) have smaller, more precocious babies than humans. Adult gorillas, for example, are significantly larger than adult humans, yet their newborns are about half the size of human newborns. Chimpanzees, which are our closest extant evolutionary relative and have a similar adult body weight to us, give birth to newborns that are around 3% of their adult size, while humans have newborns that are around 6% of adult size (DeSilva). At what point since our common ancestor with chimpanzees, did hominins start having bigger babies? Continue reading
Have you ever wondered why some animals create a nest or den for their offspring, while others carry their babies everywhere they go? These represent two reproductive strategies, or ways of producing and caring for offspring that survive to sexual maturity, called parking and riding respectively. Continue reading