How Our Genes Influence Our Desire for Monogamy

Monogamy might be more about genetics than choice.

Coyotes are fascinating creatures.

Most of us think of them as nuisances, pesky critters that invade our space, rummage through our yards, and present possible dangers to our household pets. But these relatives of wolves and dogs can do something that most of us have failed miserably at in our lives--they’re masters of monogamy.

The mating behavior of coyotes is intriguing all around.

Several males court a female, and she selects the most appropriate suitor of the bunch. The two copulate, and if the mating is successful, they become attached to one another for about twenty minutes. They can’t separate. Unlike human males, male coyotes only produce a single sperm.

If successful, the two coyotes will spend the rest of their lives together. The species is 100% monogamous.

But coyotes are exceptional in this. And the reason they’re exceptional jives with evolutionary theory. The males care for their young until they grow up and become young adults themselves. The fathers hunt and carry food back to the den in their mouths that they regurgitate and feed their babies, much like birds.

But before we proclaim victory, suggesting that coyotes are monogamous, therefore it’s at least conceivable that humans are monogamous as well, let’s dive into a bit of the research and see what science is uncovering about the genetics of monogamy.

First, we’ll start with animals and a bit of history, then we’ll get into the genetics of human monogamy.

Animal Research on Monogamy

“It could be a handy riposte for the stalwart commitment-phobe. When challenged on their reluctance to be tied down, half-hearted partners could shrug and claim their neural gene expression profiles made them that way,” writes Ian Sample for The Guardian, discussing the genetics of monogamy.

In other words, whether you court monogamy or flee from it in horror might be more biological than you think.

He’s referring to 2019 research that studied several animal species and found that genetic markers indicated a biological basis for the development of monogamy in animal species. We’re not just talking closely related species, like different types of flies; we’re talking everything from frogs to birds to mammals.

Neuropeptides are chemical signals in the brain. Oxytocin and vasopressin are neuropeptides that play a role in monogamous behavior in animals—and humans.

They’re the “cuddle” chemicals. While oxytocin encourages monogamy in females, vasopressin, also called “the monogamy hormone” by some, encourages monogamy in males.

When you inject a male animal with vasopressin, it will form a monogamous long-term relationship with whoever’s nearby. If you inject a chemical that blocks vasopressin, monogamous animals will suddenly become non-monogamous.

The California mouse is monogamous and has a high density of vasopressin receptors, while the closely related white-footed mouse does not and is not monogamous.

This pattern can be found all over nature.