Why Are Newborn Humans Useless? |Squished Pt3|

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?

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Body Hair

Apes, including humans, are physiologically riders, meaning that they carry their babies with them as opposed to leaving them in nests or dens because their breast milk composition is not suited to leaving their infants alone for long periods of time (Ross, 2001). But unlike humans, apes don’t need a tool to carry their infants in part because they have body hair for their infants to cling to but it’s more complicated than simply having body hair and a baby that can grasp it. Hair strength, density, infant weight, carrying position, adult posture, and even humidity play a part in successful infant carrying without tool use. Continue reading