January 25, 2021 by Robert Franklin, JD, Member, National Board of Directors
Anthropologist Lee Gettler and colleagues have long been major contributors to our understanding of fathers and the evolution of fatherhood. In her excellent book, The Life of Dad, Dr. Anna Machin cited Gettler who’s studied populations in the Philippines and Africa.
Machin cited Gettler for teaching us that males with high levels of testosterone tend to be more successful at attracting females with whom to pair-bond, but, when their first child is born, those same males undergo the biggest drop in serum testosterone levels. It’s long been known that new fathers experience a sharp decline in testosterone, likely an evolutionary adaptation making them more likely to care for and not be a danger to offspring, and be more attentive to the mother.
Meanwhile, among Gettler’s Filipino male cohort, those who’d partnered with a woman but had no children showed little or no change in serum testosterone levels.
Now Gettler has moved on to other things (Child and Family Blog, January, 2021). He speculates that parenting behavior by males actually predates the sharing of food among pre-humans. In fact, he asserts that parental behavior by males made the sharing of food possible. And the sharing of food among various members of a tribe or clan was one of the foundational blocks on which Homo sapiens was built.
New anthropological research offers an intriguing answer. It suggests that caring fatherhood is not only core to men’s parenting, but that it may have come first in human evolution, before fathers provided food for their offspring. Indeed, if humans had not first developed early forms of caring fatherhood, then the provider father might never have arrived: Thus, “caring dad” may have laid the evolutionary foundations for “provider dad.”…
Adult males, females, and children benefit from such sharing. Indeed, the pooling of high-energy food resources (such as meat and root vegetables) helps explain how humans evolved large, energetically costly brains that make up only a small percentage (~4%) of our body weight but require nearly 20% of the calories we burn each day. It also helps explain our unique family strategy of raising many very needy, slow-growing children at the same time, which sets us apart from other mammals, including other primates.
But why did we begin doing it? After all, although chimpanzees sometimes hunt and kill, food sharing among adults is rare-to-non-existent. So Gettler hypothesizes that, among pre-humans, males began to do childrearing work that in turn encouraged them to share the food they brought in with their offspring.
Through observation of non-human primate behaviors, my research team suggests an answer: Low-cost, basic forms of adult male care of infants, aiding mothers, helped pave the way for greater cooperation, including food sharing…
We argue that similar low-cost behaviors could have evolved in early humans and then been ratcheted up through evolutionary time. Caring would have laid the social and trust foundations for the later emergence of more proactive, riskier, more costly food sharing. Such food sharing eventually led to subsistence specialization and resource pooling that became common in human families and communities. Thus, we argue that the caring father predated the provisioning father rather than vice versa.
Plus, it seems that low-testosterone males are more likely to be generous with food and other things including services in the society at large, i.e. not limited to their immediate families.
Of course that’s just a theory on Gettler, et al’s part, but it seems plausible.
And, as we’ve long known, parenting behavior on the part of both sexes is a matter of hormones. Certain hormones like oxytocin, prolactin, estradiol and others produce parental behavior in adults. The drop in testosterone levels in males also makes male parenting behavior possible. Now, exactly why we, unlike the vast majority (90 – 95%) of other social mammals evolved those hormones in males remains a mystery. My own theory is that genetic mutation produced either the hormones or their receptors in the brain or both and that in turn produced parenting behavior in males having the mutation(s). Females then began sexually selecting for those parental traits because the male attention, protection and food sharing enhanced both her and her infant’s chances of survival.
These findings challenge how we might think about contemporary fatherhood and its potential. They highlight direct caring for children as an important feature of men’s lives from early in human evolution. This perspective questions more historically and culturally limited ways in which paternal roles have been regarded, viewed through the particularities of 20th-century industrial societies, which shaped quite narrow perceptions of men’s capabilities. Our growing understanding of the biology of fatherhood underscores the flexibility of fathers to adapt to meet the many different challenges that face parents, whether it is providing direct care to children or food and resources for them.
Allow me to phrase the matter somewhat more bluntly: it’s long past time that we stopped regarding fathers as unimportant peripheral players in the lives of children. In fact, human fathers are necessary to children’s well-being as eons of human and pre-human evolution demonstrate. Family courts and laws aren’t just behind the times, they’re positively primitive.