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Dog to Dog Aggression

Dear John,

I have a 3 yr old neutered male GSD with dog to dog aggression He went from docile to aggressive to most other dogs. I have contacted trainers, behaviorists, vets, and have been unsuccessfully working on this problem for a good 6 months. The dog is never mistreated but I think he began this as a result of being bullied in the dog park as I was socializing him. I no longer take him there but now he’s terrible with other dogs. He will remember and play with his certain dog ‘friends’ when we meet them in places other than the dog park (another regular park). He does not attack them but most others. He is a very large GSD 108 lbs and is stronger than I and knows it. Otherwise, he’s close to perfect and will behave well off leash. He’s nice to my Pomeranian as well.

This began at about 2 1/2 years of age and caught me totally off guard. I did not become tense around him and other dogs until a few months ago. One trainer had me put him in the down position when approaching another dog. It worked sometimes but I realized that it was too much emphasis on the entire encounter so I quit doing it. Now I just keep walking past the other dogs and it does work better.

The problem is still not solved and I use a muzzle in public on leash just for everyone’s protection. He loves people and is great with kids. We walk most days 3 1/2 miles with running and sometimes with another dog. This is not my first GSD and I have never had this problem before to this extent. In the beginning, I was very hopeful that this could be nipped in the bud fairly quickly but now I am not sure at all.

I try to beef up his confidence in the meantime and keep things calm. I’ll take all of the advice I can get…also thinking of having a thyroid panel done but he really has zero symptoms of that, He recently lost weight via diet, good mood and happy, loves to swim, run and chase balls…no lethargy or skin issues but he is itching right now. That began about 1 week ago. He does have some impulse control issues about getting excited about going out which is egged on by my Pom.

No food aggression, good appetite, not ravenous but eats well, good food …Nutro weight control formula, regular vet checks, does receive adequan injection monthly for hips, hip and joint supplements. That’s all I can think of.



Hi Cynthia,

I suspect the reason you may not have had any luck with trainers, veterinarians and behaviourists is you’re trying to fix something that isn’t broken and not fixing something that is broken. A lot of dog owners (and trainers, veterinarians and behaviorists) seem to think all dogs are supposed to like other dogs and expect them to meet and socially interact with strange dogs. I don’t know of any social species that does this including human beings. Suspicion is a more normal survival trait.

It’s true that some dogs (like people) are much more adaptable and not as prone to “stranger danger” agitation and dog parks tend to propagate that myth as they tend to attract what I call party dogs. These are generally certain breeds that seem more amendable and less competitive. Alternatively there are breeds that are not necessarily so but are individuals that haven’t achieved adult hood yet. I’ve seem many dogs at dog parks that I know once they hit about 18 months of age are going to get into an “incident” and learn subsequently that this is exactly what happened.

I was watching a Nature of Things documentary the other day about canine cognition and one of the scientists from a university in Newfoundland Canada (I think) was challenging the idea of dominance and some other social hierarchal behaviours in dogs. I thought her conclusions were a little weird at least based on my own 30 years of dog experience until she mentioned her conclusions were based on research based on dog park observations. I think down the road we’ll find that her conclusions are going to have be become qualified and more likely overturned. Drawing conclusions based on the way dogs behave in a dog park is like drawing conclusions about human behaviour based on watching them in church.

It’s not that dogs can’t get along with other dogs. That wouldn’t make sense either. I would argue that they are not designed to get along with strange dogs. These are the same dogs that I encourage people to refrain from walking the same route day after day. Once they hit adulthood they’re not so much walking as patrolling and it agitates them to see strange dogs on their perceived territory. The average dog owner can’t do much more then further agitate the dog by tightening up on the leash exacerbating the dog’s condition. I also argue most dogs don’t need to be walked at all. They do however need to be exercised and you can read one of my columns on the topic to learn more about the difference.

That is not to say that your dog and all dogs regardless of breed or personality shouldn’t be trained to listen and behave around all distractions including other dogs. They should learn to walk on a loose leash, come and stay using other dogs as distractions but you build up to that rather then drop them into the deep end of the pool. If you are having problems with that then I would suggest that what’s broken is your dog’s idea as to who is the teacher and who is the student. If so, I’d have a look at the method you are using to train him. I find with all dogs but particularly dogs like yours if you’re going the treat route instead of relationship training you have a hard time addressing these sorts of issues. Remember he doesn’t need to like other dogs but he does need to respect you enough to follow your direction no matter what.

I’d stick to “play dates” with a dog or dogs that he has ongoing interaction with with as most dogs do enjoy this type of familiar social interaction once they have a chance to learn each other’s idiosyncrasies and it tends to be awfully good exercise.

You may find if that his itching disappears once you adjust your expectations of him as perhaps the conflict between what you expect and what he’s capable of is stressing him out.

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7 thoughts on “Dog to Dog Aggression”

  1. cynthia

    Thanks John,
    This is the first thing I have heard that makes sense. You are right, I don’t expect him to like every dog but he is expected not to act up. I have since learned that dog parks are not a good idea for him and stopped taking to them over a year ago. The territoriality (at the regular park)you speak of makes a lot of sense as well. So many of the dog owners there try to have their dogs make friends with him, and I have to tell them ‘no’. I also like what you said about the difference between walking and exercising him. Until I began using the muzzle (maybe 1-2 weeks) he would also swim and retrieve his ball which he loves. Once I get his behavior and mine squared away, I do want to pursue an activity together–agility maybe? Thanks so much for your response. It really ALL makes sense.

    1. Hi Cynthia,

      I haven’t met him so this is just a guess but I’d look for something more like a noseydogs club (, tracking, schutzhund or a ringsport like French ring club in your area. I think he’d love it and benefit. I’ve found they help more with this sort of problem as well then typical agility classes.


  2. Gary Reynolds

    Good article and I found the info helpful with recent behavior change in my adopted Border Collie mix (Beagle, we’re guessing); but we’ve had him for 3 years and though he had to fend for himself for probably 2 years, he’s never demonstrated any aggressive behavior. He recently started chasing one of our two cats for no apparent reason other than just being close by. Last night he started growling at our other two dogs during their snack/treat in the evening. I eventually took the chew treat off him he had in his possession as their being near seemed to be the source of the problem. The other dogs were just getting too close. I lightly scolded verbally but felt it may not have been the best way to handle. Do you have any other suggestions? I do try to give him extra attention, knowing his background before we got him.

    1. Hi Gary,

      It’s very odd to see this sort of change in behaviour. I’ve seen it in the early stages of relationships and when a dog living with other dogs transitions from puppyhood to adult hood but something is missing here. If your dog has been around for a while and is an adult something is triggering the change in his attitude. Sometimes it’s a change in the way the owner handles the dog. Some dogs need a more structured relationship where there is no doubt as to who is the teacher and who is the student and failing that I’ve seen this sort of behaviour develop. If not left too long it turns around easily enough when the dog owner sends clear relationship messages. I personally don’t recommend sending those messages when the dog is asserting itself towards the cats or other dogs. It’s better to do what I call going in the side door. Less confrontation and more frequent minor requests.


  3. Dogs over the past 10,000 years or so have evolved primarily to live not in human homes, but in human streets, & have mostly come inside only within the past few generations. Street dogs tend to be highly social & gregarious, but also territorially limited: seldom do they meander more than a couple of blocks up or down the road from where they were born. They spend their entire lives within an area of less than a mile in circumference. Within that space they tend to recognize every other dog, human, horse, donkey, mule, cat, pig, chicken, and probably every other animal who frequents the territory. Dogs don’t choose to socialize with all of them, but dogs know who they all are. This is exactly the reverse of a dog park situation. Dogs are taken to dog parks from familiar territory; the dog park, even if often visited, is outside the dog’s own secure sphere. Then, at the dog park, dogs are immersed in the sights, sounds, and most especially the odors of hundreds of other dogs, almost all of them unfamiliar. The only analogy to this in the historical existence of dogs is sometimes walking to village markets with familiar people and livestock. Even in that situation, though, the dog is not alone and not going instantly from familiar surroundings to a strange place. The dog walking to a village market has the chance to become gradually acquainted with the new place and new animals one step at a time. Dog parks are a necessary way for urban pet dogs to get exercise and make friends, but in taking dogs to a dog park, dog keepers need to be aware that the experience, for the dog, is much like going instantly from a rural small town to the middle of New York City. Some do better with that transition than others, but for any dog it will be stressful.

  4. Great article. My working-line GSD has lots of dog-friends, but doesn’t befriend every single dog she meets. That’s actually in their breed standard. I also like your term “party dogs” – you nailed it. My dog is a certified tracking dog, a gun-dog (bird retriever) an exceptional disc-dog, a one-dog sled team, competition obedience etc. just to name a few. Her working drives are through the roof, and her recall is 100%. But sometimes, (not often, but sometimes) I would like to walk her calmly on a loose leash without using a prong collar. Do you think there’s any hope of this? I’m in Waterloo and I would like to get your take on this?

    1. Hi Ryan, I haven’t encountered a dog that couldn’t be taught to walk calmly on a loose leash on a flat collar. The biggest variable contributing towards the desired outcome are things like how much of the dog owner is left owner at the end of the day. From the dog’s perspective it’s worth adding that just because they behave civilly doesn’t mean they don’t have other ideas. My old shepherd used to give the eye regularly as if to say, “Can I kill this one?” For those hard core dog to dog aggressive cases you have to tap into the relationship between the dog and owner/handler and devotion towards doing exactly the job required as taught with less trying distractions.


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