Is Our Dogs’ Behavior Genetic?

Or is it all in how you raise them? Nature vs. nurture and raising a well-adjusted dog.


Dr. Ilana Reisner wanted her new Australian Shepherd puppy, Asher, to have a rock-solid temperament. She knew how tough it is to live with a fearful or aggressive dog because, as a veterinary behaviorist, she works with reactive dogs and their owners for a living. So she did everything that she advises her clients to do: she found a puppy whose parents had lovely personalities and whose breeder provided excellent socialization experiences; she brought the puppy home between eight and ten weeks of age; she continued his socialization herself; and she enrolled him in a well-managed puppy class so that he would have a chance to learn good social skills with puppies his own age.

Given that Dr. Reisner did everything that behavior experts recommend to create a confident, well-socialized puppy, she was surprised when Asher showed anxiety around other dogs in his puppy class – nervousness that only increased as he matured. Then she had some bad luck when, at age four months, Asher was jumped by an out-of-control dog, and it was a really scary experience for him. By the age of eight months, Asher was showing clear signs of fear of other dogs.

great dane puppies

Dr. Reisner has continued to work with him over the ensuing years, but he hasn’t improved; she describes him as a whirling dervish when he sees unfamiliar dogs. And yet she did everything she could to avoid this issue. Is it possible that, due to genetics, Asher’s behavior problem was inevitable? How much influence did Asher’s environment have in the development of his temperament?

Our Dogs’ Genetics VS. Their Environments

In the complex interplay between genetics and environment, sometimes genetics takes the upper hand. Researchers have tested just how far genetic influences on personality can go by breeding animals for particular temperaments and absolutely nothing else.

This sort of study is, by necessity, very long term and therefore fairly rare, but there are two well-known examples in canids. A group in Russia has bred two lines of foxes over three to four decades, selecting one line for fearfulness of and aggression to humans, and the other line for friendliness to humans.

A similar long-term project in the U.S. has resulted in a line of pathologically fearful pointer dogs. In both these cases, the lines of animals breed true, meaning that if a fearful animal is bred to a fearful animal, all of the offspring are fearful without exception, even when raised by a non-fearful non-biological mother.

How relevant are these findings to pet or working dogs? It turns out that personality is influenced by many, many genes, and if you breed for any other traits in addition to temperament, like looks or performance, then your ability to guarantee particular results in the puppy goes out the window.

In the real world outside the laboratory, genetics rarely confers absolutes; instead, it confers risks. Outside the lab, behavior problems are almost never truly inevitable. They may, however, be extremely high risk.

Which leaves us with what we have: dogs who are bred for many different traits, and as a result produce puppies with personalities mostly similar to their parents’, but sometimes quite different. Sometimes the results are wonderful, and sometimes not so much. We can decrease the risk of unwanted traits like fearfulness through careful breeding, but we can never completely weed those traits out.

Our Dogs’ Experiences

Just as we don’t have complete control over the genetic contributions to a dog’s personality, we lack complete control over the puppy’s environment. By the time the breeder and then the owner are formally socializing a puppy, the little canine brain has already gone through massive amounts of development, and as a result has gone down some roads and abandoned others. The uterus is a rich source of experience for the fetal brain, which is profoundy affected by both reproductive and stress hormones. Early life in the nest with mom and siblings is also chock full of experiences that mold a young mind. The puppy is learning his place in the world and how to interact with other dogs from very early on.

All we can do, then, is our best. We can provide innumerable positive and varied experiences for puppies to teach them that the world, in all its sometimes unexpected variety, is safe for them.

Just as importantly, we can prioritize giving dogs as solid a genetic background as possible. Temperament should be the highest priority in breeding, closely followed by physical health. Animals with questionable temperaments should not be allowed to pass on behavioral problems, either through their genes, through stress hormones in the uterus, or through modeling fearful behavior to their puppies in early life. Temperament is more important than preserving stellar conformation or spectacular performance; in fact, in breeds with small gene pools, bringing in genetic diversity from outside the breed is preferable to breeding dogs with questionable temperaments.

So the question “Is this dog’s problem genetic?” may not be meaningful, because all behavior problems are caused by genetic risk plus life experiences. However, the question “Can this dog be helped?” absolutely is.

We have powerful tools at our disposal to help dogs live in this complex human world: thoughtful breeding practices, positive socialization experiences, and loving training and management. These are the tools Dr. Reisner uses with Asher to help him live a comfortable, happy life despite his fears. There’s a lot we can do to make good dogs from the raw materials we’re given.

Jessica Hekman, DVM, MS, completed her internship in shelter medicine at the University of Florida’s Maddie’s Shelter Medicine Program in 2013. She now studies the genetics of dog behavior in Illinois, where she lives with her husband and two dogs. Check out Dr. Hekman’s Facebook page, where posts about dog brains and behavior (and sometimes shelter medicine).

Starting on September 12, Dr. Hekman is teaching an online course, “From Domestication to Inbreeding: Population Genetics and Companion Animals,” for the International Association of Animal Behavior Consultants