There are dog people. There are cat people. There may or may not be bi-petuals.
Now, there’s research. Being a dog person isn’t just a matter of choice. We may be genetically hardwired to cozy up to canines.
A few years ago, the focus of animal-preference research — yes, that’s a thing — was on the psychosocial aspects. Dog people, compared with cat people, were said to be more extroverted, less aloof, more into Frisbees, less tolerant of the smell of tuna, more into plaid shirts, more concerned about the feelings of other people, less into Emily Dickinson, more easygoing. The stereotypes loop back and become self-fulfilling — people choose the animal that fits their self-image.
Now, scientists are adding genetics to the mix.
Scientists in Sweden, using a large national database of twins and their DNA, among other records on file, have been able to tease out and begin to quantify the genetic factors involved in animal preference.
The results suggest that dog preference has a lot to do with DNA. The study took advantage of the Swedish Twin Registry, the world’s largest database of its kind, along with Sweden’s obsession with keeping careful track of everything. All dogs in Sweden must by law be registered with the Swedish Board of Agriculture. Or else.
They used statistical modeling to study dog ownership in identical twins and fraternal twins. Everybody may share the same upbringing. But identical twins share the same genome; that is, they have all genes in common. Fraternal twins have only half their DNA in common. This makes it possible to zero in on the genetic tendencies driving a particular trait.
For the all-important matter of dog people versus cat people, the main finding in the new study was that “genetic factors greatly contribute to dog ownership in Sweden, with heritability estimated to be 57 percent for females and 51 percent for males.”
They didn’t mention cat allergies, or the fact that cats can’t be trusted, and are no fun. But it’s helpful to know that dogs have somehow burrowed so deeply into our genomes.
Besides serving as an excuse for tolerating a dog on the couch, the findings begin to shed some light on co-evolution of humans and domesticated animals. Dogs came first, as we all know by now, turning up in the human fossil record and cultural remnants at least 15,000 years ago in Europe. The mystery is how the first dogs turned away from their wolfian ways and chose to linger around the campsites of bipedal hominids. Some dogs reportedly even decided they are humans.
There’s a survival advantage to having a dog around. They can warn of predators, for one thing, and chase off cats. Over time, this preference must have become biological, like preference for tea over coffee.
“The close connection between humans and their domesticates has almost certainly had significant influence on human evolution, genetics, and behavior through reciprocal influences,” the scientists concluded, writing in the journal Scientific Reports. “In view of the deep history of animal domestication (the first and oldest being the dog) and our long and changing relationship with them, this evidence may be an important first step in unraveling some of the most fundamental and largely unanswered questions regarding animal domestication — i.e., how and why?”
Carl T. Hall is a longtime union organizer in San Francisco who is now a co-owner of Word. A Café, a dog friendly coffee shop now open for business in the Bayview Neighborhood. Readers can pick up copies of Bay Woof there, too.