Intro
In this episode of “People I Mostly Admire” (Pima), economist Steve Levitt interviews Cat Bohannon, an evolution researcher and author of the book “Eve: How the female body drove 200 million years of human evolution.” The book offers fresh and surprising perspectives on the female role in human evolution, presenting new and fascinating ideas that can change one’s view of the world. Cat Bohannon’s deep knowledge about various scientific subjects and her ability to present these ideas in an engaging manner make her book an enlightening read.
Main Takeaways
Evolution of Mother’s Milk
- The evolution of mother’s milk dates back to ancient proto-mammalian ancestors, providing water, immunity, and prebiotics. Human milk is specifically designed to help newborns fight infections and aid in digestion.
- There was a historical belief that colostrum, the thick first milk, should not be given to babies, but rather to young wolves. However, colostrum is beneficial for babies as it primes their intestines and immune system.
- Male nipples can produce milk, and trans women can breastfeed using the same medical protocol as cisgender women. The male nipple is not vestigial, but rather a result of being mammals ready to produce milk with the right hormonal signal.
Role of Wet Nurses in Population Growth
- Wet nurses played a critical role in the viability of early cities and population growth due to breastfeeding being an ovulation suppressor.
- The practice of wet nursing led to more babies being born in ancient urban environments, impacting population growth.
- The female body’s role in human reproduction changes how we perceive ancient stories and population growth.
Menstruation and Pregnancy Challenges
- Women’s periods have been a subject of scientific inquiry for centuries due to the perceived costliness of menstruation in terms of blood, nutrition, and health.
- The building up of the uterine lining before the body receives a signal of a fertilized egg is a unique aspect of the menstrual cycle.
- The deeply invasive placenta in humans is the reason for the costly and dangerous nature of human pregnancies, leading to longer and more difficult pregnancies compared to other primates.
- The relationship between the fetus and the mother is not the idealized symbiotic one often portrayed, but rather a form of maternal-fetal competition, where both are vying for resources in the womb. Pregnancy is a kind of trench warfare where both the fetus and the mother are in a stalemate, each trying to survive and gain resources without harming the other.
Gynecology and Human Survival
- Gynecology is key to understanding human evolution and the challenges faced in reproduction. Human pregnancies pose significant dangers compared to other animals.
- Labor and childbirth in humans are more complex and risky due to metabolic thresholds and the size of the baby’s head.
- The advent of gynecology and the understanding of reproductive history have been crucial for human survival and evolution.
- The interdependence of societies has also been crucial for human survival and population growth.
- Lucy, a human ancestor, likely had midwives due to the obstetric dilemma of giving birth to big babies with a small pelvic opening.
- A study suggests that human ancestors faced a population bottleneck around 800-900,000 years ago, with only 1,280 breeding individuals remaining. The cause of this bottleneck is still debated.
- Human dominance as a species was not inevitable and was not biologically preordained. For most of human history, humans were prey species and not the top of the food chain.
- Collaboration and societal behavior, especially in addressing the challenges of childbirth and infant care, contributed to human success.
Mating Strategies and Power Dynamics
- The evolution of the human body, including the co-evolution of the penis and vagina, provides evidence for ancient mating strategies and power dynamics.
- Different mating strategies in primates are reflected in their body types and reproductive organs.
- Humans have medium-sized testicles, suggesting a balanced mating strategy with less male competition compared to primates with large testicles.
- The transition from matriarchy to patriarchy in human society is not clearly defined, and the discussion of ancient mating strategies sheds light on potential societal structures.
- Matriarchal baboons demonstrate that male-female relationships can influence mating patterns, and exclusive relationships and monogamy can challenge existing norms and lead to male inheritance of social status.
Author’s Feminist Perspective
- The author’s work has an explicitly feminist viewpoint, which is unusual in the field of economics.
- She discusses the notion of ideology-free writing in science and her conscious decision to deviate from that norm.
- The author shares personal stories, such as her experience of applying for a job at an escort agency and her reflection on the economic impact on women and non-binary individuals who put their bodies up for rent.
- She reflects on the challenges of writing about the evolution of the female body without mentioning her own experience of nearly becoming a prostitute.
Conclusion
The episode explores the fascinating role of the female body in human evolution and the challenges faced in reproduction. It highlights the importance of gynecology and midwifery in human survival and population growth. The discussion of ancient mating strategies and power dynamics sheds light on potential societal structures. The author’s feminist perspective adds a unique and thought-provoking dimension to the conversation. Listeners are encouraged to share their thoughts on the episode and explore the new show “The Economics of Everyday Things,” which delves into various intriguing topics.
