(Photo: Wes Siler)
Indefinitely Wild

Breed Doesn’t Determine a Dog’s Behavior

A study of 20,000 pure breeds and mutts rules out breeding as a major determining factor in a dog’s personality


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What type of pet dog is right for your family? A new study published this month in Science suggests that a dog’s breed only determines nine percent of its behavior. 

“Dog breed is generally a poor predictor of individual behavior and should not be used to inform decisions relating to selection of a pet dog,” reads the study’s conclusion. 

Focused on both mixed breed dogs and many different types of pure breed, the published paper acknowledges that, while most behavior studies predominantly focus on pure breeds, such animals represent only a small minority of the world’s total dog population. Of the approximately one billion dogs in the world, at least 80 percent are what the study calls, “free-living, free-breeding, and not under human control.” And, even in countries with high populations of pure breeds, like the United States, mutts remain very common. It’s estimated that about 50 percent of all dogs in the U.S. are mutts.

What also makes this study unique is its methodology: Where others have relied on first-hand observations by researchers, this one solicits behavioral data by surveying owners and requests genetic material from them for DNA sequencing. The published findings are based on behavioral surveys of 18,385 dogs and DNA information about 2,155 of them.

The study’s owner survey breaks behaviors out into certain categories like human sociability, biddability, and toy-directed motor patterns, and uses multiple questions in each category in an attempt to create a depth of understanding around those behaviors. It then compares those ranked answers across breeds to determine correlation. 

While some findings suggest behavior traits are heritable, the association between a breed and its behaviors is far less direct than the association between a breed and its aesthetic traits. 

“Breed offers little predictive value for individuals, explaining just nine percent of variation in behavior,” the study finds. Among the studied behaviors, retrieving was the most heritable trait, but even then, the ability for genetics to predict that behavior in an individual dog was five times lower than their ability to predict aesthetic traits. 

“Behavioral factors show high variability within breeds, suggesting that although breed may affect the likelihood of a particular behavior to occur, breed alone is not, contrary to popular belief, informative enough to predict an individual’s disposition,” the study says. 

Researchers also explored associations between breeds and behaviors with what the paper calls “behavioral stereotypes”—those being the three-word phrases the American Kennel Club uses to summarize breeds. For instance, the AKC refers to border collies as, “affectionate, smart, energetic.” The study’s findings there? “Breeds described with particular words are not behaviorally distinct from other breeds.”

As for mutt behaviors, the paper reads that, “we show that behavioral characteristics ascribed to modern breeds are polygenic, environmentally influenced, and found, at varying prevalence, in all breeds.” 

Similarly, little to no correlation was found between a dog’s size and its behavior. 

In short, every dog is an individual. You cannot expect one golden retriever to replicate the behavior or personality of another. However, prominent dog researcher Marc Bekoff is quick to point out that the study’s findings do not indicate that genetics don’t play a role in determining behavior, they just play less of a role than the popular perception of pure breeds may indicate. 

“An individual’s genetics set them up for certain propensities but do not guarantee them,” Bekoff writes in Psychology Today. “The chances of observing certain kinds of behavior will indeed change depending on a dog’s breed. This is how we got all these different-looking dogs in the first place, and their different forms followed selection for their different functions or breed characteristics.”

While it’s possible for, say, an individual Maltese to demonstrate guarding behavior, its ability to serve as a guard dog would obviously be limited compared to, for example, a German shepherd who also demonstrates guarding behavior.

Bekoff concludes that while, “a dog’s genetics are not predictive of a behavior actually being expressed…breeds can offer a reasonable starting point for setting expectations and hints at what our experiences might be.”

But Bekoff also cautions against drawing too many assumptions about behavior based on breed alone. I asked him if this study disproves the popular assertion that pure breeds offer more predictable personalities than mutts. “It does exactly that,” he told me during a phone call.

The bottom line? The scientific consensus continues to agree that it’s both a dog’s breed and the environmental factors it experiences that determine its behavior. If anything, this new study simply puts new emphasis on how important it is to train, socialize, and spend time with your good dog. 

“Breeds can hint at what a dog’s personality might be,” says Bekoff. “But ultimately it’s nature and nurture that combine to determine the end result.”

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Lead Photo: Wes Siler

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