Pit bulls get a bad rap, which is especially vexing given that no one actually knows exactly what a pit bull is. There’s no unified definition, because “pit bull” is not a recognized breed. But the label can have devastating consequences for dogs in shelters, who are perceived as less adoptable because of their purported heritage. In recent years, especially with the advent of genetic testing, some researchers have a new idea: just stop labelling mixed-breed dogs altogether.
Researchers at Arizona State University decided to do a large-scale analysis of shelter dogs by looking at every pup that came through the doors of two animal shelters, one in Phoenix, AZ and one in San Diego, CA. Shelter workers were asked to identify the primary and secondary breeds of each dog (or simply “mixed breed” if it was too heterogeneous), as is standard at most American organizations, and scientists took cheek swabs from each to test their genetic heritage. They published their results in the journal PLOS ONE.
Not only were shelter workers relatively inaccurate with their breed labels, according to the data, but even correctly-identified dogs generally got less than half of their genome from the so-called primary breed. Dogs correctly ID-ed as pit bull mixes were on average only 38-48 percent “pit bull,” here defined as having some heritage from an American Staffordshire Terrier, an American Bulldog, a Bull Terrier, or a Staffordshire Bull Terrier. The same was true for other breeds. Chihuahua mixes were generally about 38 to 39 percent Chihuahua. Poodle mixes were only around one-third Poodle.
But despite being less than half pit bull (not that there’s anything wrong with pit bulls in the first place—more on that later), dogs with that label stayed in the shelter for nearly twice as long. The average for non-pit bull types was 19.7 days, whereas pit bull mixes stayed for 37.5 days. In this study, just four dogs got a pit label without having significant pit-type DNA (at least one quarter), and in prior research there have been similarly low false positive rates. The overall accuracy wasn’t great, though. Two-thirds of the dogs had at least one of the staff-identified breeds in them, but that leaves a full third of dogs who were completely misidentified. When asked to list both a primary and secondary breed, staff accuracy dropped to just over 10 percent, and more than half of those correct IDs were for purebred dogs who happened to end up in shelters. That’s largely in line with other research, which according to the National Canine Research Council “has consistently shown that visual breed identification is very often inaccurate.”
Given how often shelter staff are incorrect, then, the researchers argue we shouldn’t be labeling these dogs at all—especially given how irrelevant breed identification is when it comes to behavior.
Purebred dogs have certainly been pushed toward certain temperaments, but as the researchers point out, the variability in behavior within a breed is generally greater than the variability between breeds. So yes, an American Staffordshire Terrier may be more prone to aggressiveness, but aggression isn’t an inherent characteristic for every dog within that breed, and there’s little research to suggest that a specific aggression trait would be passed along to a mixed-breed dog. Even purebred pit bull types are mostly non-fighters. In an interview with The Cut, Bronwen Dickey, author of the book Pit Bull: The Battle Over an American Icon notes that “The cruelty-investigators and the experts that I talked to stressed that if a breeder is rigorously selecting for those traits for generations and generations, it still is considered a very high success rate if they get one in the litter who has the fighting makeup.” He says historians noted that even in the 1920s heyday of dog fighting, only between 1 and 10 percent of pit bulls were actually used for violent entertainment. The rest were all-purpose dogs.
And it makes sense, because temperament is a complex trait that’s not easily passed down. Carol Beuchat, scientific director of the Institute of Canine Biology and a professor at UC Berkeley, writes that even though most breeders try to select for specific behavioral traits, “anybody who has tried it can tell you that producing dogs that will display the behaviors you want isn’t easy.” Behavior is the result of environmental factors and genes, and we don’t yet understand how those interplay. Beuchat notes that “A dog with high levels of aggression might have the genes for low aggression, but poor socialization or some bad experiences early in life have had a large, negative effect on the expression of that trait.”
It’s because of this lack of evidence for inherent characteristics that numerous animal associations have spoken out against banning specifics breeds. The American Veterinary Society of Animal Behavior notes that “any dog may bite, regardless of the dog’s size or sex, or reported breed or mix of breeds.” The American Kennel Club says that it “strongly opposes any legislation that determines a dog to be ‘dangerous’ based on specific breeds or phenotypic classes of dogs.” What’s more, the City Attorney’s Office of Topeka, KS notes that banning specific breeds from towns, cities, or even just apartment buildings “has generally been discredited in actual experience of cities, professionals and academic research as being both ineffective and expensive.”
For all of these reasons, researchers on this recent paper and others have suggested it might be better for all parties if shelters simply stopped identifying dogs based on their purported breeds. Even when they’re correct, they don’t tell us a lot about behavior. When they’re wrong, they can have unfortunate consequences for the dog. Instead, researchers suggest describing the dog’s physical characteristics and—most importantly—their temperament. A perky pup may not be what you’re looking for, even if it has the physical look you have in mind. Maybe you want a chilled out dog instead—even if it looks like a pit bull.