As I write this, my dog has just run off into a rare January rain with the neighbors’ dog, who walks to our house from across the arroyo and waits on the porch until someone notices him. Eventually the two of them will come back here, the muddy desert dripping off of them in clumps, and my dog will resume her place beneath my table, just beyond my feet, or on the sofa beside my wife, where she can keep an eye on both of us. As always, I am fascinated, even awestruck, by the improbable fact that she exists.
A paper just published in Nature has returned momentary publicity to the question of when and how wolves were domesticated. The dog – even the most un-doglike among them, like the teacup poodle, whose most striking canine attributes have been whittled down to a nub over generations – is still a subspecies of the wolf: Canis lupus familiaris. This is almost all we know for certain, that dogs were once wolves, and have not quite become something else. The question of how the lupus became familiaris is still open.
Early speculation assumed that humans had simply begun taming wolves: finding an orphaned pup, perhaps, and hand-rearing it, or looking for the less fearful members of the pack and cultivating relationships with them. Current ideas suggest instead that it was the wolves who did most of the work.
The newest development is that the authors of the Nature paper analyzed the genomic differences between dogs and wolves, and found variations in ten genes associated with the digestion of starch, a carbohydrate in which human staple crops like wheat are rich. The implication of their discovery is that the ability to process starch was an important factor in the evolution of the dog subspecies: canids who could eat starchy food could scrounge in early human garbage dumps, becoming habituated to human proximity and passing their carbohydrate-tolerant genes to their offspring.
The discovery is unexpected and fascinating, but it settles nothing. We remain confident from archaeological and genetic research that wolf domestication preceded the advent of agriculture, meaning that some form of dog existed while humans were still hunter-gatherers, when starch would have been less consistently present in our diets. The picture therefore cannot be as simple as hungry wolves gathering around prehistoric farming villages to plunder the trash.
Some researchers have argued that humans and wolves first came into proximity as warily cooperative hunters, an ostensibly persuasive claim bolstered by the results of a 2004 paper which found that small hunting groups working with a dog killed 56% more prey than those working without one. But because the new carbohydrate evidence suggests that the ability to process food other than game animals is essential to the identity of the dog, we are still confronted with the need to incorporate disparate, almost contradictory data.
The several attempts to establish a chronology for the domestication process have yielded similar uncertainty. In 1997, a report published in Science presented genetic evidence indicating that dogs diverged from wolves over 100,000 years ago. That report was controversial because no dog remains have ever been found from anywhere near such a remote date. A study released last year detailed the analysis of a canid skull dated to 33,000 years before the present, doglike in size but wolflike in dentition, leading to speculation that it represented a midpoint in the transition from lupus to lupus familiaris. But even this date is far removed from the 15,000 years-ago divergence suggested by a 2002 paper.
It is possible, of course, that the transition from wolf to dog took place slowly, over millennia, and that it happened more than once, with only one strain of dog surviving into the modern era. Research will continue, and unlike the question that I wrote about last week – the meaning of rock art here in the Southwest – the origin of the dog is something that we can hope to understand in the near future.
Regardless of when we know the whole story, I find it marvelous that the animal with whom we humans have formed a closer bond than any other should be a taxonomic twin to one that has become synonymous in our culture with the raider, the primeval foe, the tightening circle of fear around the lost calf or the late traveler. If we love the dog for its familiarity, our relationship with the wolf remains dysfunctional and often hostile.
Here in New Mexico, we are struggling to re-establish a healthy population of the once ubiquitous Mexican Gray Wolf. Organized resistance to the reintroduction program is mostly led by ranchers, who fear livestock predation. While environmental groups like the Sierra Club have pointed out that dogs account for five times the number of cattle kills that wolves do, and the government has instituted reimbursement programs to compensate for depredation, the debate continues unabated, usually along predictable lines. In Santa Fe, Wolves Belong stickers adorn dirty Subaru bumpers, while the Governor has announced that her administration will no longer cooperate with the federal reintroduction efforts.
I will elaborate on the subject of wolf reintroduction in a week or two. In the meantime, I cannot help but wonder if the development of the dog may not have contributed to the wildness of the wolf: that is, if sociability with humans was essentially bred out of the lupine population, leaving only the untameable wolves that are so widely and unjustly feared today. Perhaps by welcoming the dog we damned the wolf to its present predicament. It is an odd speculation, and probably wrong, but there is a seductive balance to it, as though in the calculation of the wild even the genesis of so beloved an animal had to be offset by some other cost.
My dog lies on the floor, ignorant of the classification science has bestowed on her. She does not tolerate coyotes and would be unlikely to have much patience with a wolf if she met one. But in her curled, guarded posture, alert even in sleep, she betrays the ancestry in her. She carries in her genes the foreign and the unknowable, and I value that in her as much as I do the familiar. She is the kindliest of wolves.