Peter B. Gray Ph.D.

The Evolving Father

The Human Zoo

What would human families look like in captivity?

Posted Oct 14, 2013

Human in a zoo

Imagine you were tasked with the job of crafting a new zoo exhibit featuring that least exotic of species—our own, Homo sapiens. Suppose the zoo already had enclosures featuring orangutans, chimpanzees, bonobos, and gorillas, but generous funding had made possible an ability to build a new space for displaying their evolutionary cousin, ourselves. You would appreciate that attempts were made to provide naturalistic groups for these other species (e.g., gorillas in one-male polygynous family groups). That’s for good reason, as Robert Martin notes in his book, How We Do It: “It is reasonable to assume that species-typical social patterns have some genetic basis. In captivity, primates typically show the same pattern as in the wild. For example, keeping gibbons in zoos is successful only if adults are caged as pairs, along with any growing offspring.” (p. 57)

OK, so how do you present a “natural” group of humans? Influenced by evolutionary principles, you might immediately appreciate that having a large group (tens of thousands, much less millions) of people living together in a settlement is evolutionarily novel, much less financially impractical for the zoo exhibit. You might then consider creating hunter-gatherer-like families. But that, too, can be complicated. Do you depict forager groups as described by 20th century anthropologists in Australia, a continent entirely of hunter-gatherers? Or maybe among recently studies African hunter-gatherers such as the Aka or Hadza, for whom some of the richest data exist? Then again, today’s foragers employ hunting technologies such as bows and arrows that haven’t been around long, so maybe it would be better to imagine how foraging ancestors lived at the dawn of our species’ existence in Africa around 200,000 years ago. You appreciate that this is still a somewhat arbitrary cutoff, recognizing that animatronic earlier hominin social groups could also be interesting (like these), even if slightly creepy to some kids visiting the zoo. 

If this exercise in creating a human zoo exhibit is beginning to seem strained or strange, you realize through a google search that previous attempts have been undertaken, as in London in 2005, and in other cases with extremely ethnocentric and offensive results. You inform your thought process by learning more about foragers, comparative primate research, and reproductive physiology and genetics, all couched within an overarching evolutionary theoretical perspective. You puzzle over how to recognize the multi-tiered nature of human social groups—from families to camps to something like tribes. Eventually, you settle on how to organize your human zoo exhibit.

You create an exhibit with around 25 people in a multi-male, multi-female group. Nested within that group are sets of four reproductive partnerships—three of those socially monogamous, and another consisting of a man with two women. Each of the women has children of various ages, spaced around 4-5 years apart. There are older individuals—a few more grandmothers than grandfathers—who also seem taken by their youngest kin. As for the four partnered men, they engage in various paternal behaviors, although these are clearly constrained by the nature of the zoo exhibit. The men forage for food resources that have been planted within the exhibit in hard-to-reach nooks (“enrichment” activities for the guys), and the men share those resources with other group members, including their family members. The males seem to pay close attention when other human observers get too close for comfort; when some adolescent males visiting the exhibit antagonize group members, one of the protective males throws feces and rocks at one of the lads, hitting him upside the skull. When a stray coyote wanders into the enclosure one night, interested in nabbing an infant, a dad and mom together chase it away. The several males also linger close to their reproductive partners and kids much of the day but also sleep next to each other at night. The dads sometimes hold their young children, but to many observers’ surprise don’t seem to exact punishment when the kids stray too close to the dangerous electrical fence that keeps them from leaving. You also notice one of the dads sharing stories with his near-adolescent son, catching words with deeper social insight. 

After about a week of this exhibit attracting record crowds at the zoo, you awaken to a middle-of-the-night phone call. A security guard explains that the humans have somehow created fancy new tools that enabled them to sneak out of their exhibit in the dead of night. The human enclosure is now empty. In a sense, the zoo inhabitants have moved beyond their foraging-like social mixture to the wider world of the present. Oh well; it was a fun experiment imagining the social lives, including the roles of fathers, among our early human forebears.

Some recent works that focus on evolution and human reproductive behavior include:

Dixson, A. F. (2012). Primate sexuality, 2nd Edition. New York: Oxford University Press. 

Martin, R. (2013). How we do it: The evolution and future of human reproduction. New York: Basic Books.

Geary, D. C. (2010). Male, female: The evolution of human sex differences, 2nd Ed. Washington, D.C.: American Psychological Association. 

Gray, P. B., & Anderson, K. G. (2010). Fatherhood: Evolution and human paternal behavior. Cambridge: Harvard University Press. 

Gray, P. B., & Garcia, J. R. (2013). Evolution and human sexual behavior. Cambridge: Harvard University Press.

Hrdy, S. B. (2009). Mothers and others: The evolutionary origins of mutual understanding. Cambridge: Belknap Press of Harvard University Press.

Walker, R. S., Hill, K. R. Flinn, M. V., & Ellsworth, R. M. (2011). Evolutionary history of hunter-gatherer marriage practices. PLoS ONE 6, e19066.

Marlowe, F. (2010). The Hadza: Hunter-gatherers of Tanzania. Berkeley: University of California Press.