What Female Animals Are Teaching Us About Human Female Health
Dr. Barbara Natterson-Horowitz is leading the way to linking evolutionary biology and veterinary science
Hiya!
So, I recently stumbled upon some research by Dr. Barbara Natterson-Horowitz that led me down quite the rabbit hole. It turns out that Dr. Natterson-Horowitz has quite the resume. She’s a cardiologist and evolutionary biologist at Harvard University, a professor of cardiology at the David Geffen School of Medicine at UCLA, a scientific researcher, and co-author of the New York Times bestseller “Zoobiquity.” Not to mention all the lectures she’s given and the awards she’s won.
In short, Dr. Natterson-Horowitz is blazing a trail for a much-needed but sorely lacking research topic involving women’s health. Not only is she bringing crucial attention to the neglected subject, but her niche is a revolutionary yet incredibly simple approach — combining veterinary science and evolutionary biology like never before. In other words, she’s studying how other female species in the animal kingdom evolved to overcome issues related to female health that human females struggle with, from diseases to pregnancy and childbirth.
Some Background
I discovered Dr. Natterson-Horowitz when I read an article in Scientific American penned by her about her research. In it, she summarizes her dedication:
“Numerous female animals have evolved over hundreds of millions of years to resist diseases that claim the lives of millions of women a year. Unraveling the biology behind these changes could lead to lifesaving interventions in women’s health.”
In the process, Dr. Natterson-Horowitz has hosted seminars regarding menstrual difficulties in great apes (including human females) and other animals, published studies about ovarian cancer in pythons, flamingoes, humans, and fish, and much more.
Throughout her impressive research, Dr. Natterson-Horowitz wrote how she realized that, in some ways, human females might have more in common with other female animals than with the human males in our lives.
Human Exceptionalism & Medical Gender Bias
Dr. Natterson-Horowitz expected her research to make a bigger impact than it has. Based on the responses she got, she realized anthropocentrism (human exceptionalism) was still “deeply entrenched in our medical traditions.” Anthropocentrism is the belief that we Humans are superior to the rest of the animal kingdom—that we’re Humans, not animals.
The truth, of course, is that Humans very much belong to the animal kingdom. We are animals—mammals, to be more specific. Dr. Natterson-Horowitz shares her personal experience in her SA article:
“People haven't always been comfortable accepting that humans are animals. It has been my experience that human health professionals reflexively assume diseases they treat in their patients are unique to our species. (They aren't.)”
In addition to our superiority complex, we’re prone to another bias — gender bias in medical research fields — which has caused lots of problems.
It wasn’t until 1993 that the National Institutes of Health (NIH) began requiring their human clinical trials to include women. Before that, even studies about diseases women are more prone to experiencing than men didn’t require researchers to include any women participants. If you can believe it, the NIH didn’t mandate the use of female lab animals in preclinical safety studies for new medical treatments until 2015.
The argument for excluding females from biomedical studies was the fear that the female menstrual cycle — and the physiological variations caused by it — would complicate the results. Since males don’t experience such fluctuations, it was thought using males exclusively would yield more consistent results, and it was assumed that male-only studies that would work for men would also work for women.
As Dr. Natterson-Horowitz summarizes in the SA article:
“Yet however well intended these investigators might have been, excluding females from studies proved enormously damaging to women's health.”
I guess I can sort of grasp the logic behind excluding females from scientific medical research to have fewer variables to worry about — but it doesn’t take much critical thinking to see the errors in this philosophy. After all, the argument for women’s exclusion due to the variables involving menstrual cycles would complicate results and conflict with the assumption that anything that works for men will also work for women.
The Study
After reading Dr. Natterson-Horowitz’s SA article, I found a 2022 paper published by her, UC Santa Barbara associate professor of anthropology Amy Boddy, and Dawn Zimmerman, the director of international programs for the Veterinary Initiative for Endangered Wildlife in PNAS Nexus, summarizing years of research concerning “female risks for common diseases across multiple species.”
Based on scientific evidence, humans still possess ancient molecular pathways and genes associated with resistance to common diseases that we share with other female animals. The trio’s paper provides ample examples of remarkable ways female animals have adapted that can inspire new ways to protect and improve women’s health. Here are just a few awesome animal adaptations they found:
Pausing Pregnancy Windows
Some female animals have a sort of built-in birth control, a phenomenon called embryonic diapause. It allows over 130 other female mammals, including fruit bats, bears, deer, and seals, to pause their pregnancies for a few days to 11 months.
Figuring out how embryonic diapause works in various female animals could show us new birth-control methods or ways of preserving embryos during in-vitro fertilization. Especially since some human female reproductive pathways are similar enough to other female species to potentially replicate the ability.
Extended Motherhood
While human males can father children well into their 80s and even 90s, female fertility diminishes after age 40 and plummets by age 50 thanks to menopause. Even pregnancy by age 35 is considered a geriatric pregnancy and presents a higher risk.
But the Greenland shark can become pregnant well after turning 200 years old. Understanding this extraordinary ability has the potential to help women experiencing infertility or difficulties conceiving, particularly after 35 years and older — especially since women in the United States are choosing to put off motherhood until after establishing a career and getting married or decline it altogether.
Defeating Hypertension and Heart Failure During Pregnancy
Giraffes, it turns out, are rockstars at managing hypertension (aka high blood pressure) during pregnancy. This is extra impressive because, thanks to their incredible height, giraffes have the highest blood pressure of any species, when they aren’t pregnant.
Cracking pregnant giraffes’ cardio secrets could save countless human female lives since hypertension and heart failure are risk factors affecting 6 to 8 percent of pregnancies. Did I mention that a third of pregnancy deaths in the United States are because of heart problems?
Perspective Shift
A unique combination of global warming, the pandemic, and feminism seems to have shined attention on the severe lack of research regarding female health. We’re quickly learning that while male and female humans are similar in many ways, we’re also biologically different in some crucial ones. It’s long past time we dedicate time and resources to studying and understanding women’s health.
The same trio of events also seems to affect our outdated beliefs about human exceptionalism. Dr. Natterson-Horowitz and other researchers are discovering that we have far more in common with the animal kingdom than ever thought possible. Following Dr. Natterson-Horowitz’s lead in finding the overlaps between evolutionary biology and veterinary science can further help us move beyond our bias and better care for female health—human or not.
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