There is no free love in the state of nature. Animals are incredibly picky about who they mate with. We have inherited the neurochemics that drive this behavior. That's why the fieldnotes of a primatologist sound weirdly similar to the lyrics to a country-western song. A biology textbook sounds uncannily like a soap-opera script. Our romantic ups and downs are often hard to make sense of, but the mating behavior of earlier species helps clarify our non-verbal impulses. Here are a few primate lessons about the ons and offs of relationships.
Monogamy is not the norm among apes except for gibbons. How do gibbons keep their relationship alive? They sing a duet when they wake up each morning. The sound is amplified by an inflatable sac in their throat, and the neighbors make judgements. If their song is perfectly coordinated, they get respect. If their song lacks the proper timing of male and female parts, the neighbors try to exploit the couple’s weakness. Gibbons have an eerily familiar way of dealing with this. If a male intrudes on the couple’s home range, the husband attacks, and if a female intrudes, the wife attacks. The lesson? Work on your duet before the neighbors hear the strain in your relationship.
Female orangutans judge a male by his looks. They go crazy for those big flaps. How can a guy get them? They grow when a male dominates a territory. It’s not just a matter of strength, but of hormone levels that rise when no other male is around. The lesson? Spending too much time with your buddies can limit your appeal.
Bonobos have a seductive reputation, but the truth is less inspiring. Female bonobos fight with each other for the privilege of courting the son of the alpha female. This eerily familiar behavior can be explained by what biologists call the “sexy son hypothesis.” A female mammal has a low lifetime reproductive capacity, and the best way to spread her genes is to have prolific sons. Choosing a prolific father helps you do that. And that’s one reason why female mammals are attracted to the big kahuna despite the frustrations of that choice. The lesson? Chemistry is not necessarily a good guide to long-run compatibility.
You might think this has nothing to do with you, since you are not trying to spread your genes. But the underlying point is this: animals don't make with just anyone. Animals are very picky about who they mate with. They have strong inclinations toward one individual and not another, despite all the frustration it causes. When we feel that frustration, we look for "good reasons" to explain it. It helps us to know that our strong feelings about mate choice come from neurochemicals that were naturally selected for reproductive success rather than "good reasons."
There's a lot more on this in my book I, Mammal. For a free pdf of the chapter called "Sex and the Status Hierarchy," contact me at innermammalinstitute.org.