There’s one book in particular that you’ll have no trouble finding as you browse the science aisle at the bookstore this summer.
On the cover of Domesticated: Evolution in a Man-Made World, a reasonably menacing gray wolf stares intently back at you. His eyes are fixed, and the hair on his head is standing up. He has long, slender limbs for running down prey, and broad jaws for eating it. Standing beneath the big bad wolf and barely a quarter his size is a tiny, harmless, button-nosed bichon frise. (The photo is a composite. I was concerned enough about the bichon to check the photo credit!)
What is most remarkable, as evolutionary biologist and author Richard C. Francis points out in Domesticated, is that the wolf and the bichon pictured on the cover have nearly identical genetic codes. “Even though we were able to get from wolves to chihuahuas and great danes,” Francis says, “the basic wolf traits were not modified significantly except in the sense that we juvenilized them.”
The journey from wolf to dog was much longer than the one from dog to highly differentiated breeds like poodles, schnauzers, golden retrievers, etc. That long phase was essentially natural selection—survival of the fittest—that occurred gradually after humans transitioned from a nomadic to an agricultural society. The shorter phase to the dozens of species we recognize today was more the product of intentional breeding.
“There was probably a period of thousands of year when wolves followed humans around,” Francis says. “Wolves are natural scavengers, and humans are kind of messy. The wolves who got the scraps had to be the ones who could best tolerate human proximity. The tamer wolves could get more scraps.”
The wolves who didn’t mind being around humans had lower levels of hormones associated with fear response. Those same hormones are associated with other puppy-like characteristics, including floppy ears, upturned tails, white coloration, and shortened snouts. Many generations later, those wolves with lower levels of fear-response hormones had essentially become dogs.
“In the early stages of domestication, the process isn’t any more sped up than in garden-variety natural selection,” Francis says. “When humans take control of the breeding, then it definitely accelerates. You can really see this kind of acceleration with the advent of the kennel clubs in the 19th century.”
The English bulldog in the 19th century looked much more like a generic dog than it does now. As dog show judges began prizing particular characteristics, breeders intensified those traits by breeding single individuals with hundreds of mates or even by mating fathers and daughters. The downside is that most of the defects we associate with purebreds now is the result of their practices.
Evolutionary biology is heady stuff—microbiology, neuroscience, sociology, natural history and archeology rolled into a single field of study—but Domesticated is a book more for a popular audience than the scientific community. Francis has a Ph.D. in neurobiology and a deep understanding of the science that underpins the book, but he presents it in Domesticated in relatable chapters about domesticated animals including dogs, cats, pigs, and even camels.
“I didn’t know if I was going to include the camel initially,” Francis says. “I went on a safari to the Red Sea by camel, and I was thinking as I was riding this thing that it was an improbable animal to domesticate. They’re huge.” And not especially pleasant. “They’re notorious for getting snippy. They’re also famous for their flatulence, which I experienced. I tried to stay near the head of our group to avoid that!”
In Domesticated, Francis uses stories like his camel adventure to break down and demystify science—establishing the building blocks and building on those concepts in later chapters. He is already at work on a book about the development of yeast for beer, wine and baking.
“I want to write books about seemingly difficult topics that my parents could read and understand,” he says. “It’s a challenge, but it’s a fun challenge. The creativity for me comes in that. The facts are there, but it’s presenting them in a way that’s entertaining. That’s rewarding to me.”
Scott Porch is an attorney and contributes to Kirkus Reviews and The Daily Beast. He is writing a book about social upheaval in the 1960s and '70s.