Pet Boarding & Daycare

How Much Does Breed Really Affect Canine Behavior?

How Much Does Breed Really Affect Canine Behavior?

By Michael S. Gould

A study from UMass Chan Medical School, which surveyed more than 18,000 dog owners and analyzed over 2,000 dog genomes, revealed that dog breed does not fully determine personality. Ultimately, the study found that just 9% of the variation in an individual dog’s behavior can be explained by its breed.1 

This topic is something I have researched for quite some time. In 1982, I started studying breed-specific behavior in relation to aggression with the New York City police department. Since then, I have been deemed by the courts as a subject-matter expert in various aspects of animal behavior, including the use of force and canine deployment. 

In 2000, I founded Hounds Town USA, a fully interactive doggie daycare that has since become a national franchise. In any one of our 30-plus facilities, around 30% of the dogs we host on any given day are considered “bully” breeds. These can include German Shepherds, Pit Bulls, Dobermans, Rottweilers—breeds that segments of our society have deemed “dangerous.” However, we interact with these types of dogs on a daily basis and welcome them into our facilities with a no-discrimination policy. This is because, as the study revealed, a dog’s breed does not wholly determine a dog’s personality. In fact, researchers found that, across individual dogs of the same breed, there were significant variations in behavior.

The study noted that humans didn’t begin intentionally breeding dogs until 2,000 years ago, and it wasn’t until the 1800s that humans began selecting dogs based on the traits that we commonly associate with purebreds today. Yet, modern breeds are often characterized by human-like temperaments that aren’t actually dependent on breed.

  For example, Golden Retrievers are known for their friendly natures. However, researchers found that a Golden Retriever is only marginally more likely to be friendlier than a mixed-breed or another purebred dog, such as a Dachshund.

“Although ‘friendliness’ is the trait we commonly associate with Golden Retrievers, what we found is that the defining criteria of a Golden Retriever are its physical characteristics—the shape of its ears, the color and quality of its fur, its size—not whether it is friendly,” wrote the senior study author, Elinor Karlsson, PhD.

Meanwhile, Pit Bulls are very powerful and have certain breed instincts of their own. They are widely discriminated against and assumed to be aggressive. Although they were historically bred to fight bulls, this does not mean they have a genetic predisposition to act on that training. 

Proper socialization and training are key to encouraging good dog behavior. Unfortunately, many of these breeds are typically removed from their litters too young and not socialized correctly with other dogs. Think of it like children being isolated from other children; when there’s a lack of socialization, they are more likely to become startled and hostile.

Additionally, there’s no evidence that a properly socialized dog has any more or less of what we call a “bite inhibition.” This is usually learned early on in the litter during nursing and carried throughout a dog’s life with humans.

Unfortunately, the aggressive behavior associated with most “bully” breeds is usually fostered by humans. At some point in a dog’s life, somebody mismanaged, misunderstood and failed to socialize or train the dog properly. This can lead to insecurity, fear and protective instincts, which can all manifest as aggressive behavior.

Throughout my career, I have come to find that there is no replacement for consistent, proper socialization and a natural pack environment. Dogs are pack animals, and we have seen in our Hounds Town USA facilities that, in a properly curated pack, dogs will establish their own hierarchy and self-regulate their behavior in the pack. Whether it’s a Pit Bull or Frenchie, most dogs will benefit from this type of environment, regardless of breed. 


1. Fessenden, J. (2022, April 28). UMass Chan Study Shows Canine Behavior Only Slightly Influenced By Breed. UMass Chan Medical School.

Michael S. Gould began his canine career in 1982 as a New York City Police Officer and one of the first members of the Department’s elite Canine Unit. After a long and successful career on the police force, Mike’s unique canine training experience and background organically lent itself to opening a doggie daycare business and dog sitting facility. In 2000, Mike opened his first Hounds Town USA dog boarding location in Port Jefferson, Long Island, New York. Since its inception, Hounds Town has cared for more than three million canine visitors.