Humans love dogs. We have done for, literally, thousands of years. In fact, some evidence suggests that dogs were first domesticated in Siberia around 23,000 years ago. Back then, they were likely still pretty similar to their wolf predecessors.

Now, there are hundreds of dog breeds, all with different perceived traits. But according to a new study, much of the way each individual dog behaves isn’t linked to breeding at all.

Canine breeding as we understand it today is still quite a new phenomenon. In fact, breeding for certain physical traits became popular in the Victorian era, which was only about 150 years ago.

Since then, breeds have earned reputations. Pit bulls, like American pit bull terriers and Staffordshire terriers, are widely considered aggressive. English bulldogs are considered to be calm, and golden retrievers are thought of as bouncy, friendly, and smart.

But research from the University of Massachusetts Umass Chan medical school indicates that some of these reputations may be unfair. 

Owners should disregard breed ancestry

The study—which analysed 18,385 pet dogs, half of which were purebred—found a variety of behaviors displayed, but, for the most part, they weren’t linked to any specific breed.

That said, there were a few similarities in dogs of the same breed. The authors wrote: “Breed offers little predictive value for individuals, explaining just nine percent of variation in behavior.”

While some traits could be linked to genetics, others were likely down to other factors, like environmental influences.

Interestingly, researchers found that pit bulls, as well as retrievers, were more sociable and comfortable around new people.

But because of their reputation, pit bulls are on the receiving end of a lot of prejudice. They’re one of the most likely breeds to end up in a shelter in the US. And, when they’re there, they struggle to get adopted.

This has led to the founding of organizations like Adopt a Pit. The Miami Valley-based nonprofit launched in 2013 to support the adoption of pit bulls and other breeds that are considered to be aggressive.

Remarking on the study findings to the Guardian, lead author Dr. Elinor Karlsson said that the study shows that owners “should pay much less attention to all the stories about what their dog’s breed ancestry says about their behavior and personality.”

Instead, she said they should “pay attention to the dog sitting in front of them.”