Turns out we may be unfairly stereotyping dogs.
Modern breeds are formed around aesthetics: the bat ears of chihuahuas, the curly coat of poodles, the hot dog shape of dachshunds. But races are also frequently associated with certain behaviors. For example, the American Kennel Club describes border collies as “affectionate, intelligent, energetic” and beagles as “friendly, curious, cheerful.”
Now, genetic information from more than 2,000 dogs, along with self-reported surveys of dog owners, indicate that a dog’s breed is a poor predictor of behavior. On average, race explains only 9 percent of behavioral differences between individual dogs, researchers report April 28 in Science.
“Everyone assumed that breed predicted dog behavior,” said geneticist Elinor Karlsson of the University of Massachusetts Chan School of Medicine in Worcester at an April 26 news conference. But “that had never been asked particularly well.”
Geneticists had asked the question before in different ways. A study in 2019 looked at whether genetics could explain collective variation between breeds and found that genes could explain some of the differences between, say, poodles and chihuahuas (Serial Number: 10/1/19). But Karlsson and his colleagues wanted to know how much variation in the behavior of individual dogs can predict by breed.
To study variation at the individual level, the team needed behavioral and genetic data from many dogs. This is how they developed Darwin’s Ark, an open source database in which more than 18,000 pet owners answered surveys about the characteristics and behavior of their dogs. The survey asked more than 100 questions about observable behaviors, which the researchers grouped into eight “behavioral factors,” including human sociability (how comfortable a dog is with humans) and docility (how responsive it is to commands). ).
The researchers also collected genetic data from 2,155 purebred and mongrel dogs, including 1,715 dogs from Darwin’s Ark whose owners submitted dog saliva swabs. The inclusion of mongrel dogs, or mutts, sheds light on how ancestry affects behavior while removing purebred stereotypes that could affect how the dog is treated and thus behaves.
Studying stray dogs also makes it easier to separate traits from one another, says Kathleen Morrill, a geneticist in Karlsson’s lab. “And that means that on an individual basis, you’ll have a better chance of mapping a gene that’s actually related to the question you’re asking.”
The team then combined the genetic and survey data from the individual dogs to identify genes associated with particular traits. The new study revealed that the most heritable behavioral factor in dogs is human sociability, and that motor patterns, such as howling and retrieving, are generally more heritable than other behaviors.
That makes sense, Kathryn Lord, a canine evolutionary biologist in Karlsson’s lab, said during the briefing. Before modern breeding began in the last two hundred years, dogs were selected for functional roles could provide, such as hunting or grazing (Serial number: 04/26/17). Today these selections still appear in breed groups. For example, herding dogs on average tend to be more docile and interested in toys. It also follows that, within breed groups, individual breeds are more likely to show certain motor patterns: retrievers, unsurprisingly, are more likely to recover.
Still, although race was associated with certain behaviors, it was not a reliable predictor of individual behavior. While retrievers are less likely to howl, some owners reported their retrievers howling frequently; Greyhounds rarely bury toys, except for a few.
The research solidifies what people have observed: Dog breeds differ on average in behavior, but there is a lot of variation within breeds, says Adam Boyko, a Cornell University canine geneticist who was not involved in the study.
Surprisingly, size had an even smaller effect, virtually none, on an individual’s behavior, despite the barking commonly associated with small dogs. Boyko points out that small dogs can often behave worse than large dogs, but rather than that being built into their genetics, “I think we typically tolerate misbehavior more in small dogs than in large dogs.”
As a dog trainer, Curtis Kelley of Pet Parent Allies in Philadelphia says he meets a dog where he is. “Dogs are as individual as people,” he says. Breed gives vague guidance on what kinds of behaviors to expect, “but it’s certainly not a hard and fast rule.”
If a person is looking to buy a dog, he says, they shouldn’t pay too much attention to the dog’s breed. Even within a litter, dogs can display very different personalities. “A puppy will show you who they are at eight weeks,” says Kelley. “It’s our job to believe them.”