And even reliable identification of the ancestry of a mixed-breed dog by itself wouldn’t help us predict an increased likelihood of known, genetically driven traits — say, the blood-clotting disorder that plagues Dobermans or the heart defects of Cavaliers. The parents of any mixed-breed dog have, by definition, waded out of the closed gene pool that makes purebred dogs such fertile ground for genetic research. The inevitable inbreeding of purebred populations, combined with a phenomenon called genetic drift, gradually decreases overall genetic diversity; more and more animals have fewer and fewer variable traits, including characteristics that aren’t deliberately selected for or against. But as researchers found with a colony of wolves in Sweden, even inbreeding so severe that it causes infertility can be reversed by the introduction of just one outsider. So, if we could demonstrate such a thing as “acting like a Beagle” or “acting like a Basenji,” there would be little reason to expect either one from the offspring of a Beagle/Basenji pairing.
But what about those purebred Basenjis and Beagles and Cattle Dogs and Afghans and Golden Retrievers? Can’t we expect them to behave consistently in ways that resemble the work at which they were once selected to excel?
Yes and no.
The case of my Annie, the lovely, fawncolored Greyhound camouflaged in a pile of pillows on my couch as I write this, may be instructive. She came into rescue directly from the breeding farm. It’s obvious why she never made it to the racetrack. When my other Greyhound, Henry, a racer successful enough to stay alive until retirement at four, barks and quivers at the living room window at the sight of a squirrel or takes off in an ecstatic (albeit futile) pursuit of a jackrabbit at the local off-leash park, Annie looks up blandly and then, with a clear “Whatever,” goes back to her interrupted sniffing or chewing or resting.
And yet, every single one of her ancestors, going back scores, perhaps even hundreds, of generations, was hyper-motivated to chase. They would not have had the opportunity to reproduce otherwise. Racing Greyhounds are bred for two things only: a keen inclination to pursue small, fast-moving furry things and the physical ability to do it at great speed. Racing industry insiders estimate that only about 70 to 80 percent of the dogs who result from this ruthless selection process are keen enough to race. Now, a 75 percent incidence of a trait sounds pretty high. You’d certainly take those odds in Vegas at the roulette wheel. But this is a trait that’s already extremely common across the species; it is, in all likelihood, the most widespread of the predation behaviors of hunting, stalking, chasing, killing, dissecting and eating first observed and described by the famous wolf ethologist, David Mech. Most dogs already do this. If you take more complex behaviors that are actually selected against in the wild, like compulsively fighting other dogs and failing to respond to the doggy body language equivalent of “crying uncle,” for example, your odds of reliably producing the behavior through artificial selection go down dramatically. This explains how so many of the so-called “game-bred” dogs from fight busts (like the ones rescued from Michael Vick’s fighting operation) have gone on to live companionably with other dogs as relative couch potatoes in normal homes.
Reliably increasing the likelihood of complex behaviors through selective breeding isn’t easy. And racing Greyhounds are one of only a handful of dog breeds where this is still even attempted. Since the advent of modern purebreds in the late 19th century and the subsequent closing of breed registries, selection criteria have focused almost exclusively on appearance. Qualities of temperament are sometimes mentioned, although not in ways that can be practically applied in the show ring, where — as biologist Ray Coppinger has pointed out — the behavior required is standing, and to a lesser degree, trotting alongside a handler. Most purebred dogs come out of this selection system.
So these days, when people look fondly at the breed they fancy or angrily at the one they fear and say to me, “They’re not like other dogs,” I remind my little voice to recite, “Well, actually, they kind of are.”