It’s conventional wisdom that many dog breeds behave in a certain way because “it’s in their genes”. From border collies herding to huskies howling to labrador retrievers fetching, there are a lot of breeds that we expect should act a certain way. But that expectation is wrong. A new study found that breeds play a much less important role than thought, with only 9% of dog behavior that is explained by breed.

Previous studies had found some genetic links between breeds and behavior, but they only looked at averages across breeds instead of comparing individual dogs. That’s why a group of researchers from the University of Massachusetts now decided to create their own database, called Darwin’s Ark, collecting data on thousands of dogs across the US.

They set up a website in which dog owners uploaded data about their dogs and answered questions about physical traits, such as how tall their dog is, and about their dog’s behavior, such as whether they howl or if they avoid getting wet. Owners answered more than 100 questions, leaving the team with 18,000 survey responses.

“Even if the average is different, you’ve still got a really good chance of getting a dog that doesn’t match what people say that breed is supposed to be,” Elinor Karlsson, co-author of the study, said in a statement. “For the most part, we didn’t see strong differences in breeds, but there are some behaviors that are connected to breed more than others.”

Whoof, whoof

As well as doing a big survey, the researchers sequenced the DNA of over 2,000 dogs, half of which were mutts (mixed breeds), which made it possible to differentiate between breeds and behaviors. If certain breeds were tied with certain behaviors on a genetic level, mutts with more ancestry from a breed should share that breed’s traits, the researchers explained.

They found some behaviors, like howling, had a stronger connection to specific breeds. Bloodhounds and beagles, for example, are more likely to howl than other dogs. Meanwhile, border collies tended to be more responsive to directions, while mixed-breed dogs with border collie ancestry were also likely to have that characteristic.

However, other behaviors, such as how easily a dog is frightened, had no relationship to the breed, despite stereotypes about some types of dogs being more afraid than others. The size of a dog also had very little to do with the ability to predict how a dog was going to behave. Larger dogs weren’t calmer than small dogs, as people sometimes think.

Overall, the researchers said the breed isn’t a good way to figure out how a dog is going to behave. This has a lot of implications for the owners, which should pay less attention “to all the stories about what their dog’s breed ancestry says about their personality” and instead pay more attention “to the dog sitting in front of them,” Karlsson said.

The findings came as another study recently revealed that different breeds have different life expectancies. The analysis of over 30,000 records of dog deaths in the UK, collected between 2016 and 2020, showed that Jack Russel terriers have a life expectancy of 12.72 years, while French bulldogs tend to have a much shorter life of just 4.53 years.

The study was published in the journal Science.