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Beagles are scent hounds, prone to wander as they follow their noses. But Bonnie the beagle is a couch potato.
Beagles are known for chumminess. Clyde the beagle, however, enjoys his independence.
Beagles are noted for their gentleness, but gentle would not describe Mikey the beagle’s rapid-fire high-jumps.
Beagles, reportedly, don’t make good watch dogs. But Rocky the beagle alerts his family to the slightest disturbance.
Such discrepancies are explained in a sweeping study published Friday in the journal Science. It found that, despite conventional wisdom, breed doesn’t much predict personality traits in an individual dog.
The research on the genomics of dogs reveals that breed accounts for only 9 percent of the variation in behavior. It means that behavior within a breed varies about as much as behavior between breeds.
So descriptions of border collies as smart, retrievers as outgoing, and bulldogs as courageous are merely stereotypes.
A dog, it turns out, is a dog unto itself.
So true, said Heather Sabia, owner of beagles Bonnie and Mikey.
“I would say beagles are stubborn, some more than others. But you can say that for any breed,” Sabia said. Among the beagles, “there’s a lot of individuality.”
Louise Sabia, Heather’s mother, owns beagles Clyde and Rocky. Louise said beagles came into her family in the 1940s, when she was a child and the beloved family mutt, Patches, was killed by a car. Patches had a friend – a beagle that lived one street over.
“Every day after Patches died, that beagle came to our house and waited for Patches to come home,” Louise Sabia said. “My mother was so impressed that she went and got a beagle.”
In the 1960s, after Louise married and Heather was born, Louise’s brother brought them a beagle that someone was giving up.
“We’ve had beagles ever since,” Louise said.
Between the two, they’ve had a dozen beagles over the years.
“I just love their size, not too big that you can’t pick them up and hug them, and not too small. And I love their big, soft ears,” Heather said. “They like to be petted and they’re loyal. But each one is different.”
Now science explains it.
Researchers surveyed the owners of 18,385 dogs, roughly half purebred – 128 breeds were represented – and half mixed-breed. They asked owners to answer dozens of questions about their dogs’ behavior. Researchers also obtained saliva samples from 2,155 dogs and sequenced their DNA.
They found that, though behavioral traits can be inherited, behavior crosses breed lines.
“Modern dog breeds are less than 160 years old,” researchers wrote in their report, “a blink in evolutionary history compared with the origin of dogs more than 10,000 years ago.”
Modern dog lines date to Victorian England, when people started inventing breeds by selecting for traits based on how they wanted dogs to look.
More than 80 percent of a dog’s appearance can be tied to DNA, the study found.
But the genetic traits that determine behavior have been around a lot longer than the breeds, so dogs have much behavior in common.
The study showed that behavioral traits ascribed to modern dog breeds are determined by multiple genes, influenced by many environmental factors, and found in all breeds in varying degrees.
Researchers discovered 11 genetic markers associated with certain behaviors. But none of the markers was breed-specific.
Some behaviors are rooted in a dog’s genes, such a trait among border collies to respond well to training, researchers found. Mutts with many border collie ancestors tended to respond well to training, too.
But researchers identified no marker in the genes of Labrador retrievers to indicate sociability, a trait for which they are known. And they found little connection between breed and aggressive behavior, which could affect perceptions of breeds that have been deemed dangerous.
Researchers said dogs are a good resource for studying the genetic basis of personality traits because much is known about them – they live in millions of homes, sharing environments with humans, and they receive sophisticated medical care, including for behavioral disorders.
But researchers issued a word of caution: “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.”
Louise Sabia could have told them that.
“I really don’t know much about the breed,” she said. “I just love the dogs.”