Finding Australopithecines, Part 2: Love and Sex

This the second part of a series of posts on how I put together a plausible behavior pattern and psychology for the species, Australopithecus afarensis, for my upcoming novel, To Give a Rose. In the first installment, I talked about how I approached the project and I established my use of basic terms–“foot-ape” for australopithecine, and “man, woman, and child” for the adult male, adult female, and immature stage of
any hominoid, including the living apes.

All You Need Is Love

Sexuality is obviously an important facet of any mammal’s behavior, since that is how we reproduce ourselves. And foot-apes were clearly deeply social creatures, since their closest modern relatives, humans, chimpanzees, and bonobos, all are. And obviously these two facets of life were connected for them in some way, because sexual intercourse is, by definition, an interaction between individuals. But that’s about all we know for sure.

To write the book, I obviously had to do better.

The general social behavior of the foot-apes in Rose is similar to that of chimpanzees and bonobos today in that they live in flexible fission-fusion communities of several dozen individuals of both sexes and all ages. “Flexible fission-fusion” means that the membership pf a community is not always all together but instead spends time divided into subgroups of varying membership. We humans follow the same pattern, although our communities are larger and more complex. This is entirely in keeping with expert speculation.

But, when it comes to sex, I depart from expert opinion (at least as it stood when I was researching for the story), as I mentioned in the earlier post. The common idea was that australopithecines were monogamous  and that males, freed from fighting over females, cooperated to provide their mates and children with extra food.

Monogamy, of course, seemed unlikely to me. When humans are monogamous, it’s because of complex cultural structures that I doubt an ape could develop–and many human cultures don’t even prize monogamy. But even if foot-apes were monogamous, and even if being monogamous led to men arguing less, why would arguing less result in cooperation? Why would a man spend his time feeding another man’s child?

True, groups of brothers or cousins might work together as a reproductive team–technically, that is known as kin altruism. The idea is that since a man’s nieces and nephews carry some of the same genes he does, supporting them is almost as good as supporting his own children. In chimpanzees, bonobos, and many human cultures, it is the females who disperse at maturity, leaving males to live with their relatives, so the scenario is plausible. Equally plausible is that men might work together being doing so benefits both of them–that’s reciprocal altruism, I’ll scratch your back if you scratch mine.

But none of those scenarios have anything to do with monogamy. In other species, like lions, where brothers do act as reproductive teams, they also mate with the same females. Monogamy doesn’t necessarily preclude cooperation among males, but it does not foster cooperation, either.

As it turns out, polygamy provides a better reason for males to cooperate than monogamy does.

As a mental exercise, let’s think about successful reproductive strategies for a hypothetical mammal. These creatures want to pass on their genes. To do that, they can either have as many offspring as possible and hope some live long enough to reproduce in turn, or they can have fewer offspring and work to protect and support them–or they can pursue some intermediate strategy. The key is that quantity and quality are always at odds–the more attention one gives per offspring, the fewer offspring there can be, and vice versa.

Our hypothetical species is a mammal, so the females lean towards parental quality, but males can do quality or quantity, depending on how many females they mate with. Obviously, whether males are promiscuous or not, they’ll prefer monogamous females. Nobody really likes competition. But for the monogamous male, female monogamy is critical–if he’s going to spend his entire reproductive career raising her children, they’d better be his.

Now, he can hedge his bets by also having a few casual sexual encounters on the side, but if all the males are doing the same thing, then his primary mate must logically be somebody else’s secondary. Also, while the number of males a female mates with has no bearing on how many children she has, females, too, take a risk in committing to just one mate. Suppose he has a hidden genetic disorder? What if he dies or abandons her? She has reason to hedge her bets, too.

So, let’s say our hypothetical species has a sexual system where most individuals are promiscuous, but unevenly so. Each has one, perhaps two, primary mates, but also some number of more casual contacts. In this system, no male can ever be sure he is a child’s biological father, but he has a good chance of it if he is the mother’s primary lover. He can therefore comfortably give that child most of his parental support–while reserving a little extra for the children of his other lovers, who could be his but probably aren’t.

A human man following this strategy would be a good provider to his wife, while contributing to the college funds of his mistresses’ children. If he visits prostitutes, whose chances of bearing his child are very low but not zero, he pays them fairly.  His wife, meanwhile, presumably has a few lovers on the side and occasionally prostitutes herself for extra cash, so the family finances balance out.

The curious thing about our hypothetical scenario is that it means a child can effectively have more than one father. Obviously, only one male contributed sperm to that child, but since the mother’s lovers don’t know which of them it was, they all have an interest in the child’s welfare. If our hypothetical creatures are all honest and open about their sexual behavior and don’t fight about it, then these “co-fathers” can act as a team, working together for the sake of their common lover and her children. Of course, each man will belong to multiple such teams, at varying levels of commitment.

Non-monogamy will thus have produced male teamwork.

If our hypothetical beings sound morally reprehensible, it might be because the genetic strategy scenario is inherently selfish and utilitarian. Fortunately, real animals almost certainly don’t think this way–how could they? They don’t know about genetics. Even human animals, who do know about genetics, usually have sex because they feel an urge. We’re even less likely to care for children with genetics in mind.

Genetic strategy scenarios explain the real sexual and parental behavior of various species quite well because urges are also, to some degree, the result of genes. Individuals whose urges do not lead them to reproductive success don’t pass on their motivations. But to understand the mind of an animal, human or otherwise, it is necessary to understand the urge.

So, what do our hypothetical bet-hedgers feel like?

For their system to work, their males need some psychological mechanism for coupling their degree of parental involvement with their partner’s degree of sexual involvement. The simplest mechanism I can think of is love.

If these beings’ sexuality is a medium of social connection, then then both sexes will tend to choose sexual partners whom they like as people–and they’ll have the most sex with the people they like best. Since friendship is generally mutual, degree of sexual involvement will tend to be mutual as well; a male’s favorite lover is likely to choose him as her favorite lover in return. Further, since they like each other so much, the couple probably spends a lot of time together, even when not having sex. That has the effect of automatically bringing the man into frequent contact with the female’s offspring. Since proximity fosters social connection, he’s likely to grow to care about them–and to want to care for them.

The same mechanism will bring him into contact with the offspring of his other lovers and he’ll come to care for them, too, but to a lesser degree–thus his paternal investment will be proportionate to his various lovers’ sexual investment in him and hence to his chance of actually having sired the children.

In this hypothetical community, all males work together to support all children, not because the children are theirs genetically (though they could be), but because they are children, and deserve it–and yet everybody knows that each male has his favorites, usually the offspring of his favorite lover. For these, he will give more, risk more, and express affection more, not because he is more likely to have sired them, but because he loves them.

And if one of his favorites is not his biological child? It doesn’t matter. Love is love. Natural selection is only the mechanism that produced the behavior pattern, not its underlying meaning. Just as a bird’s song is no less beautiful for having a genetic basis, love is no less love for having evolved.

All of which is not to say that animals with a different behavior don’t love, but their love could well be different–or maybe love can evolve in many different ways, just a beauty can.

Humans follow this hypothetical scenario, although our sexual behavior is strongly shaped by cultural variation, including complex sexual taboos. Also, some of us really are monogamous, not because the taboo says so, but because we like our favorite lover so much that we don’t want to divide our attention. We still can come to love children who aren’t ours.

Foot-apes follow the same pattern but in a simpler, more direct way.

In Rose, foot-ape men do not provide directly for women and children, but they do help them indirectly, as chimpanzee men do–by defining and defending a community territory and by alerting other community members to the location of food. They are playful and indulgent with children within their community and sometimes serve as babysitters (chimpanzee babysitters are always supervised by the mother, while foot-ape babysitters are more trusted). Men sometimes adopt orphans. Foot-ape men also champion their favorite children socially, I don’t know whether chimpanzee men do.

All of which is to say that, among foot-apes as among humans, sex doesn’t make a father; love does.

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About Caroline Ailanthus

I am a creative science writer. That is, most of my writing is creative rather than technical, but my topic is usually science. I enjoy explaining things and exploring ideas. I have one published novel and another on the way. I have a master's degree in Conservation Biology and I work full-time as a writer.
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One Response to Finding Australopithecines, Part 2: Love and Sex

  1. Pingback: A Novel Passage | The Climate Emergency

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