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Nature versus nurture is an age-old question, but as it relates to the drivers of canine temperament, there is an answer. Here it is…

What I have learned in my adult years is that life experience has a funny way of humbling you.  Of causing you, at times, to consider certain strongly held beliefs and question their accuracy.

The 18 months I spent with my Linus, my Sweet Baboo, did just that for me.

It was during those 18 months and the years after that I have been exploring the question Nature or Nurture as it relates to canine temperament.

Canine Temperament – My Life Experience

Nature vs Nurture and Canine Temperament

Not a day goes by that I don’t think about Linus.

Not one.

I am reminded of him on every car ride, on every walk, and every minute I am out in public with Sulley or Junior.

PTSD?  Perhaps.

Something as simple as driving up the road to the event grounds of a recent dog show with Junior would have sent Linus into a frothing frenzy.

Being stopped by kind admirers who wanted to say hello to Junior would have resulted in one of two reactions from Linus, completely dependent on whether or not those kind people had a dog with them.

Dog shows were generally safe with Linus. Anywhere else required a muzzle.

And going through a drive-thru for a hamburger treat for my handsome Winner’s Dog would have been out of the question with Linus.

Linus and Junior were nurtured.  They are loved.

They were both trained at the same place, took handling class from the same instructor, lived across from the same neighbors, enjoyed the cushy comforts of the same beds, and received love from the same two kids.

The only discernible difference between these two dogs, with the exception of how they were raised as puppies in the breeders’ home, is their pedigree.

This has been my life experience.  However, an “n” of one is insufficient to thoughtfully explore the question of nature or nurture and the subject of canine temperament.

So I set out to see what others in the big dog community had to say.

Canine Temperament Facebook Survey

I reached out to several large breed Facebook groups posing the following question:

What do you think? Is canine temperament PRIMARILY driven by:  Nature (Genetics) or Nurture (Upbringing)? 

I removed the ability for participants in the poll to add a metric and forced them to choose either nature or nurture.  The results were quite eye-opening.

Interestingly, in the two Mastiff Groups and the Great Dane Group, on average three-quarters of the respondents said that nurture or a dog’s upbringing was the primary driver of canine temperament, while on my personal Facebook page it was the exact opposite with 71% saying nature was the primary driver of canine temperament.

Because I predicted this would be a difficult question for people to answer definitively, I purposefully didn’t include a “BOTH” option.

While I have no way of knowing how many people simply chose not to respond because they couldn’t choose one over the other, I did have a total of 36 people who commented that they felt BOTH nature and nurture were equal drivers of canine temperament.

Many of these people said that they couldn’t choose between the two options so they didn’t vote.

As interesting as these results are, I do wonder whether the results would have been different had I posted this poll in a few other breed groups; Newfoundland, German Shepherd or Saint Bernard owner groups for example.

In addition, because so many respondents said “BOTH,” I wonder if over time the numbers would gradually converge at a 50%/50% split between nature and nurture.

Here are a few comments I received during these surveys:

Canine Temperament Facebook Survey

“I think both..but more of the upbringing then anything else…it’s not the dog…it’s the owners!!!”

“I think it is both. Nurture brings out the characteristics nature placed there”

“I think nurture has a lot to do with it but so do genetics. I don’t think I could vote for one or the other they both play into it. Just like with kids.”

“Temperaments are genetic, behavior is learned.”

Had I taken this poll 10 years ago, I would have answered “nurture” with the majority without hesitation.

What the Experts Say About Canine Temperament

I recently came across two fascinating research studies that I think are both compelling and seemingly definitive in answering the question of nature or nurture as it relates to canine temperament.

Russian Fox Experiment

Canine Temperament Silver Foxes
Image courtesy of

The first is the Russian Fox Experiment which was started in 1959 by geneticist Dmitry Belyaev and the Institute of Cytology and Genetics.

This four decades-long experiment sought to examine the difference between tameness and domestication of silver foxes in Siberia.

From the Domesticated Silver Fox website:

“If you were to gain access to a lion cub, you may be able to raise it to be friendly towards humans and other animals. But, that lion’s offspring would be as aggressive as it’s wild African ancestors if not tamed in it’s early years. Also, there is still a slim chance that your own tamed lion could attack.  It’s still a wild animal, no matter what.  Domestication, on the other hand, is a slow process in which each generation of an animal grows closer to humankind, a trait that Belyaev believed was written in the creatures’ genes.”

Belyaev used selective breeding in this experiment.  He used a fox’s response to humans (tameness) as the sole determining factor and only bred the top 4 – 5% tamest foxes.

The resulting kits were all raised the same, without much interaction with humans other than during the tests themselves.  Here is a summary of the results:

  • 2nd Generation: Approachability increased. Foxes aggression started to disappear and was completely gone by the 3rd
  • 4th Generation: Foxes started to wag their tails and approach humans voluntarily. Started to allow humans to pet and carry them.
  • 6th Generation: Foxes started to follow humans and even lick them like dogs.

In addition to observing changes in the animals’ neurochemical and neurohormonal mechanisms, the ultimate conclusion that Belyaev came to as it relates to fox behavior was that the difference between tame and aggressive foxes was almost entirely genetic.  Click here for a great video summary of Belyaev’s work.

Canine Temperament and Dogs Decoded

Another terrific exploration of canine temperament is in the PBS NOVA documentary Dogs Decoded.

The fact that wolves and dogs are 99.8% genetically identical caused Hungarian researchers to try and answer the question “Is it the way we raise them [nurture], that makes a DOG?”

They wanted to find out whether the special relationship we have with our dogs was due to nature or nurture.

Researchers took a litter of 5-day old wolf cubs from a Wolf Sanctuary in Budapest and raised them in human homes with their new adoptive parents caring for them 24 hours a day.

The humans carried the cubs everywhere and bonded with them as they did with the control group of domesticated puppies.

With the exact same upbringing, wolf cubs started to trend toward wild wolves as early as 8 weeks old. 

For example, the wolves lacked the cooperative and social skills that were seen in the puppies. They disengaged through their body language and lack of eye contact when presented with toys and other stimuli that attracted the puppies. They showed extreme possessiveness over things they wanted and were increasingly destructive.

By four months old the wolf cubs were returned to their pack due to the increasing risks of keeping them in the home.

The conclusion Hungarian researchers drew from this study was that it is “impossible to turn a wolf into a dog no matter how much he is loved and nurtured.” They determined that what makes a dog, a dog, is the years of domestication by humans.

My Conclusion – Canine Temperament is Not a Zero-Sum Game

I believe the results from the two experiments I just summarized are abundantly clear.

While I believe it is in fact nature, not nurture, which is the PRIMARY driver of canine temperament, one doesn’t necessarily discount the importance of the other.

I have no doubt that the folks who voted for “nature” in my Facebook survey also believe that early training and socialization of puppies is absolutely critical to their development.

And that those that voted for “nurture” also believe in the importance of finding a quality, reputable breeder.

My own writing here on this blog affirms my stance on both:

So many of us have witnessed the devastation of a “normal” puppy being “ruined” by a cruel or uncaring environment. 

It is often these dogs who are able to come back from a horrendous upbringing and with love, desensitization, training, and a nurturing environment to be healthy, well-adjusted canine good citizens.

In spite of the evil that has been inflicted on them, they are able to overcome the odds stacked against them.

The question is, what if that puppy were not “normal” but the result of years of breeding poor temperaments?  Would the same amount of nurturing have the same positive effect?

Nature or Nurture

My last point is this.

Can a puppy who is born from parents (and grandparents) with questionable temperaments go on to live an otherwise “normal” life?

Possibly.  The litter that Linus was born into proves that that is true.

However, what happens when those questionable temperaments go on to breed more questionable temperaments?

How is this any different then, instead of selecting for tameness, Dmitry Belyaev selected for aggression, or fear, or timidity?

Is that not what breeders are in fact doing when they are breeding dogs with questionable temperaments?

My objective with this post was to share my thoughts, some interesting research and, in the end, to encourage those of you who use the safety net of good nurturing to excuse poor breeding practices, to reconsider your stance.

I warned you I was opinionated.

[This one is for you, Dad.]

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  1. This is a great post. And the answer, I believe, is it takes BOTH good breeding and proper socialization for the dog to reach full potential. Good socialization and training may ameliorate poor breeding/inherited tendencies, but isn’t a magic wand. And yes, aggression tendencies and even “bad brain wiring” can be inherited. I’m glad Linus and Junior have such a caring, devoted person willing to go the extra mile to ensure the best life possible for them.

  2. This is an excellent topic. As a former dog obedience instructor, I saw for myself that irresponsible breeders of both purebreds and mixed breeds produced pups that had difficulty behaving as a socially acceptable dog. Pups born in a barn to puppy-mill parents with little social interaction often ended up in new homes or shelters because they just couldn’t “love” their people.

    When I selected my latest show dog puppy, I made sure that the parents had great temperaments first and then wonderful conformation traits to produce a winning pup…nature is very important in my mind. Nurture certainly can help develop a pup into a good citizen from a poor beginning.

  3. I read a theory that you can influence dogs in either behavior direction by about 15-20 percent or so depending on nurture (or lack thereof) from where they started base temperament-wise (genetics). I think that’s probably largely true.

    1. Interesting! I hadn’t heard that statistic before. I will have to look into that. If it’s true, it makes sense and is completely consistent with my findings relative to the impact nature has on a dog.

  4. I read a theory that you can influence dogs in either behavior direction by about 15-20 percent or so depending on nurture (or lack thereof) from where they started base temperament-wise (genetics). I think that’s probably largely true.

  5. I have two VERY mixed breeds. Both rescued at 12 weeks, both raised by me and my children. They have many things in common, but their personalities are completely opposite. Is this breed specific? I see many qualities their breeds are noted for, esp. in Beau who is an Anatolian Shep and has a very strong protective streak. I believe that both nature and nurture have strong components, but personality is the most important.

    1. Thank you, Heather. Yes, my guess is your dogs’ personalities are so different because they are so different genetically. Whether it is the breeds they are mixed from or the genes passed down from their parents, my guess is you are looking at a great example of nature vs. nurture.

  6. Wow. This is a great post. I currently live with a sometimes dog-reactive and prone to resource guarding mutt. I have no idea what her parent’s temperaments were like, as I adopted her from a rescue group when she was around 4months old (with no siblings or parent dogs present). I agree that prior to having this dog, I definitely fell into the category of assuming that proper socialization made a good dog (or the “not bad dogs, bad owners” thought process). However, my current pup went to puppy socialization classes and was trained very similarly to my previous dog, and resulted in a very different adult temperament. Now that I have a dog-reactive dog, I am much more aware of how many good dog owners struggle with behavior concerns. As owners, I definitely feel that we can make a positive impact on helping our dogs be the best versions of themselves, but the studies you listed in this post help reaffirm my new view that nature is a huge part of a dog’s temperament.

    1. So well said, thank you! I am sorry for your current struggle. Sadly, I know how it feels to have a dog that, no matter how much training or behavior modification you do, the underlying temperament is basically unchanged. Like you, I was not a believer until I experienced it first hand. My hope is that this post and others on this topic will be shared broadly so that the “not bad dogs, bad owners” judgement isn’t a blanket placed on all dog owners with dogs who struggle with inner demons.

  7. Interesting project; love it. Both, of course, are at play. I know dogs from calm, friendly breeds who are on edge all the time and vice versa. Though breed does provide some degree of temperament predictability. At least in general terms.

  8. Two interesting studies along with your polling results. I’m still not sure I could come down on one side. I think about that Virginia woman who was mauled by her dogs. My understanding of their sad circumstances is how neglected they were because her father didn’t see it as his responsibility to care for his daughter’s dogs while she was going through a divorce/break up. Setting aside how a father could neglect living creatures precious to his daughter, there are the poor dogs suddenly thrown outside, starving, and lonely. The nurturer in their life yanked away from them. So did nature or nurture or both or something else or a combo instigate the attack on the person who loved them and saved them? This topic is certainly worthy of further study. Great post!

    1. Thank you, Irene! I will have to read that story. It sounds incredibly sad and unfortunately, likely preventable. In cases like that, my guess is there was much more at play that would cause dogs to maul a human. So sad.

  9. This is super interesting to me! We have two dogs, one that we got when she was six months old and one we got when he was 8 weeks, and their personalities could not be more different! Our younger one is definitely more protective and observant, while our older (she’s only 2, he’s 1) is more happy-go-lucky. I believe it’s absolutely a mix of nature and nurture!

  10. Great topic! Puppies even at 7 or 8 weeks of age show various temperaments, so I think breeding has a lot to do with their “personalities.” But upbringing is also very important, especially during their early fear periods that puppies have. I have seen that it is very difficult to get dogs out of these fears when they had a bad experience as a young pup.

    1. I completely agree, Sandy! I almost fear the fear periods, as odd as it is to say. That said, I have heard some breeders with poor tempered dogs blame owners for what did or didn’t happen during a fear period. These periods are so distinct in some dogs, that you are right, one small negative experience can have a lasting effect on a dog. Great point and thank you!

  11. Fascinating post. I tend to think it is down to breed but the is because dogs like Dobermans are known to be good guard dogs, chihuahuas and Yorkies ‘yap’ a lot. But as you say, the importance of nurturing in a positive and encouraging environment must make a big difference.

  12. I read your letter to Linus and it is heart-breaking. While I think that nurture plays a big part of an individual’s disposition, I do believe that some individuals, (dogs and other species) have a strong genetic makeup that influences them more than the environment can compensate for.

  13. Fascinating post! Loved the research you shared. It really is interesting how much genetic disposition can account for. I think you could see this just by looking at different breeds and Breed groups. Yes, they are all dogs, but they are bred to do specific and different task, and each is drastically different. However,every temperament must be nurtured.

  14. Training a dog and treating it well obviously will have some kind of effect on how the dog acts and behaves, and is very important in the proper development of a dog, but I believe it mostly comes down to the traits the dog is born with. It honestly baffles me how weird people get about this stuff when it comes to dogs – no one would bat an eye if I said that, for instance, a tiger is aggressive/etc because of its nature, but when it’s a dog then suddenly it’s 100% the fault/result of the owner’s treatment of the animal.

    1. So well said, Sybella! Thank you! When I wrote this post I knew some people would take offense to the idea that nature contributes more to temperament. You are right, for some reason people hold dogs and dog behavior to a different standard than other animals. Some breeders and owners make excuses for dogs with poor temperaments – “oh, he is just shy,” “she just likes her mommy,” “he just needs more socialization,” or “she needs more time to warm up to people,” etc. and breed them anyway. And so the continuation of poor temperaments continues and often worsens. 🙁

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