Dog/Dog Aggression, or Is It?

Christine Hibbard, CTC, CPDT

One of the most common calls we get from prospective clients starts with something like, “My dog is aggressive with other dogs, can it be fixed?” I’ve learned over the years that dog/dog aggression is sometimes in the eye of the beholder. The situation is further complicated because there are different types of dog/dog aggression.

Normal Dog PlayDogs playing
Sometimes, what an owner describes as dog/dog aggression is actually normal dog play. The way dogs play can seem scary to some human beings. These owners are overly conscientious about their dog’s behavior and his/her interaction with other dogs. While being conscientious about your dog’s behavior is a very good thing, like any good trait, it can be taken to an extreme. I sometimes wish I could wave a magic target stick that would make some overly conscientious owners worry less by transferring some of their worry and concern to owners who do not have enough of it. There’s a hilarious blog called Three Woofs and a Woo published by a photographer. She has wonderful shots of dogs playing.

Playground Bully
Some dogs never learned the manners of polite dog play society. They are like some people, just kind of clueless about how their behavior affects others. Jean Donaldson calls these dogs “Tarzans”. The most common sign of a playground bully is that the dog just doesn’t read cut off signals from their playmate. The other dog throws all kinds of body language that says, “OK, we’re done now, that’s enough play from you” and these bully dogs just don’t take the hint. Some dogs handle bullies quite well while others, well; they get a bit snarky when being mugged rudely by another dog who just doesn’t know when enough is enough. These dogs are rude, but not what we would call “truly dog aggressive”.

dog dog aggressionFear Aggression
Many owners believe that in order for their dogs to be mentally healthy, they must go to the dog park, or have social interactions with other dogs of some kind. This is not always the case. The reason that a dog is afraid of other dogs can stem from several causes. Some puppies were not exposed to other puppies during their socialization window. The socialization window is the first 18 to 20 weeks of a dog’s life and it’s the most important developmental learning period in a dog’s life. Puppies who never learned how to read other puppies’ body language and play cues can be afraid of other dogs later in life. Imagine if you lived at home with your brothers and sisters and never saw other children until you were 16 years old. When you finally left the house to go to high school, you’d probably be pretty uncomfortable around teenagers your own age, right?

Some dogs have had one or more traumatizing experiences from their interactions with other dogs. These experiences might have been terrifying, but not result in any physical damage. The damage comes in the form of fear of other dogs. When I see young puppies at the dog park being knocked down, run over, and played with inappropriately for their age, I cringe. What may seem funny or cute to the owners who think they are doing the right thing by “socializing” their puppy with other dogs inappropriately may be setting that puppy up for fear aggression around other dogs later in life. Its inappropriate to socialize a young puppy at the dog park where you can’t control the play interaction. If you have a puppy, find a Puppy Kindergarten that focuses on lots of supervised, off leash play with other age appropriate puppies. I’ve had clients call me because their dog was brutally attacked by another dog and now their dog is afraid of all other dogs. That’s the problem with fear; it has a tendency to generalize.

Leash Reactivity (aka Leash Aggression)Dog pulling on leash
I don’t like the term “leash aggression” because many of the dogs that react badly on leash by growling, barking, and lunging at other dogs are not aggressive. They’re reactive. You can tell whether your dog is exhibiting dog/dog aggression vs. leash reactivity by answering a simple question, “How does your dog play with other dogs off leash?” If your dog plays well at the dog park, but acts aggressively toward other dogs on leash, you have leash reactivity. If your dog displays fear aggression towards other dogs off leash, you have what most people call leash aggression.

Sometimes the most difficult cases for me to handle are the ones where the owners have never let their dog off leash around other dogs based on their reaction to other dogs while ON leash. I got a call from a woman who adopted a black lab mix from a shelter. Whenever she took the dog outside for a walk and encountered another dog on leash, she said her dog “was uncontrollably aggressive”. She had never let her new dog play with other dogs off leash because she was afraid of what her new dog would do. I decided to have a look for myself, or I should say I decided to let my dog Conner have a look for himself (see my colleague Greta’s post about Canine assistants for dog/dog fear & aggression). My dog Conner is absolutely amazing with other dogs. He just “speaks dog” with the most beautiful, calming body language that he throws at other dogs.

Dogs playing tugI had the owner stand with her dog on the sidewalk. I got Conner out of the car a block away. As we walked closer to her dog, I saw her dog put his ears up and rotate them out (sexy ears!) and then he started prancing and throwing play bows. As we got even closer, he starting barking hysterically and lunging on leash. Her dog wasn’t aggressive. He was leash reactive. He was so desperate to get to the other dog to play that he acted like a total lunatic. When I told the owner to drop her leash, I dropped Conner’s leash and totally appropriate and hilarious play ensued. It’s wonderful to see an owner cry tears of happiness.

We had some work to do with that dog, after all, while the owner was relieved her dog wasn’t dangerous, she still couldn’t walk him in the neighborhood acting like a total hysteric every time he saw another dog, but we knew what we had and could fix it relatively quickly. The way we treat leash reactivity and leash aggression can be quite different, but to treat it appropriately, we’ve got to know what we’ve got; hysterics, fear, or aggression?

Dog/Dog Aggression
Dog/dog aggressionWe do encounter what we call “true dog/dog aggression”, but it’s the most rare type of dog/dog aggression. Some dogs just find fighting with other dogs incredibly reinforcing. Other dogs, because of their breeding, or how they’ve been handled, or both, actually will kill another dog. This type of dog/dog aggression is quite rare compared to the dog/dog aggression that we see that is fear based.

These cases are difficult because of the time and resources that it takes to counter condition this behavior. Performing this type of work to help these dogs takes controlled environments, a great deal of time, and many, many stimulus dogs before we begin to see any effect. Often the cost and time are prohibitive and we’re left with two choices; the 3 Ms (a lifetime of Management/Muzzles/Medication), or euthanasia.

Do you have stories from your trips to the dog park that you’d like to share? Have you or are you dealing with leash reactivity? Tell us your stories or share your thoughts. We love to hear from our dog owners.


  1. says

    I have a pitbull very nice with people and small dogs runs up to everyone rubbing her head on everyone.We want to get a new dog but my dogs reaction around bigger dogs on the leash is scary. she jumps up and down whines she doesn’t bark. Im scared if we let her off she going to hurt another dog… When she was younger I gave a her a few play dates but she about 3 years old and hasn’t been around dogs for awhile. I have never let her off the leash with a dog bigger or the same size as her. She loves small dogs though.. what to do. Please email me back

  2. daishawn swafford says

    I have a pitbull mixed with bull dog very nice with people and small dogs runs up to everyone rubbing her head on everyone.We want to get a new dog but my dogs reaction around bigger dogs on the leash is scary. she jumps up and down whines she doesn’t bark. Im scared if we let her off she going to hurt another dog… When she was younger I gave a her a few play dates but she about 3 years old and hasn’t been around dogs for awhile. I have never let her off the leash with a dog bigger or the same size as her. She loves small dogs though.. what to do. Please email me back

  3. says

    This is a challenging issue for owners, and due to the risk of injury if you misjudge the situation, really requires the hands-on assistance of a qualified professional to assess and help you. If you’re in the greater Seattle-Tacoma area of WA state, please fill out our contact form at If not, we recommend consulting to find a qualified professional in your area.

  4. says

    We have experienced technical difficulties related to an overwhelming amount of spam on our blog. We believe the issue is now fixed and apologize for the delay in approving and responding to comments. We are working to respond to recent comments, but are unable to send private email responses. Thank you for your patience.

  5. Ruthless says

    Our one year old mastiff puppy is fine with 98% of dogs, on or off leash. But there are times when she is reactive and growls/advances on other dogs and we aren’t sure why. Is she afraid? Does she want to play and is provoking them into chasing her, as she does with our other dog. We took her to puppy social classes 3 x a week if not more from when we got her at 12 weeks until 8 months. We just finished our second tier of obedience. This happens off leash and on. It’s upsetting for the other owners, she isn’t trying to bite the other dogs but it looks bad because she is big. I always make her sit when she acts out-I try to correct the behaviour but it is so random I can’t tell what dogs will trigger this reaction. So no off leash privileges for now, and I spent the rest of the walk putting her in the down position when passing other dogs and wouldn’t let her return sniffs . It’s frustrating, I don’t want my dog to scare people.

  6. Alyssa says

    I can’t stress how useful our behavioural trainer has been for assisting us with our yorky x who has leash reactivity to the point that she would redirect it onto us… it’s been 2 weeks since we started the course and quite honestly, already the change is remarable. Our other dog, a staffy, is social with everybody, everydoggy and everything.. but I do have a question regarding some behaviour yesterday and something I’ve started to occasionally see.. whilst sniffing a new dog yesterday, she barked to say hello as she normally does.. that’s always been the case, but she also gave a little growl that, to me, sounded like she was uncertain of this new friend… yet she still wanted to play and did not snap at her… it was slightly different to a play growl though. The message I was getting was ‘I like you… but are we friends? or will you decide to snap at me?’ also, interestingly, when my dog decided that the best way to engage with this dog was to play with a toy, offering it to her new friend, (she finds this helpful when helping a fearful dog socialise)… her friend didn’t understand the playful growling and why she was doing that whilst offering the toy… it was like the other dog was afraid of playing? and maybe my dog was picking up on it? I’d be interested to hear people’s thoughts.

  7. Courtney says

    I had a rescue dog that took the opportunity to kill another dog when he had it. We only had him for a few months and although he was great with JUST us as the family, it was extremely frustrating to deal with! When we first got him the people said he is super friendly, great with other dogs, etc, etc…. And they also claimed to have gotten him from an animal shelter. When we got him, we noticed the aggression little by little each day. It got worse with time I guess after the honey moon stage? He was also 95ibs. of pure muscle – dogo argentino! Beautiful but strong! Anyways we started taking him BEFORE we noticed the aggression to the dog park, just a few minutes a day to see how he would do there. He seemed great on leash for the most part in the first couple of weeks so we thought we would take a chance. Well we went to the dog park and he first started showing signs of dominant behavior?? No growling but when a dog came up to smell his butt he would either hold his head extremely high, tail flagging rapidly back and forth, and all muscles bared. NOT GOOD. Or a dog would try to smell his butt and he would try to sit on the dog. So we stopped taking him for awhile because of these signs. I took him about 5 times as he needed running space (we live in an apartment and although active people, he needed ‘free’ time.” I kept a close eye on him, and he USUALLY listened. Then the second stage of aggression started… He started lunging at every single dog he saw, trying to pick a fight. ANY DOG, not just one or two but any. Then he started lunging at kids, adults… anyone… We decided a muzzle for him as the risk was to high! Get this, he broke his leash to go after another dog. THANK GOD I was able to jump on him and some lady lent me her leash to take him back up to our apartment, but still as if that wasn’t scary enough! I love my dog, but I also care for the safety of everyone else. Now please understand, he was wonderful in our home. No food aggression, growling, barking, potty trained etc. He knew house etiquette and followed the rules. Now things got even worse when people would come to visit and he would corner them in our home. The last incident was with my moms little dog unfortunately. I was walking with him and my brother walked my mom’s dog. Our dog got off of his muzzle and suddenly pulled the lead so hard I lost it!! Heart breaking this little dog didn’t make it through the shaking of my dog. It was traumatizing to say the least. We made the difficult decision to put him to sleep as obviously we loved our dog but again loved other people/animals as well. We had before this incident tried to find trainers who specialized in our breed of dog. He was also crossed pit. So you get a dogo/pit = a very powerful dog that if neglected throughout it’s life (he was already older when we finally got him) can be extremely dangerous! We got turned down by a few trainers as they said they can deal with “fear aggression”, but not “true aggression”. They did not have the knowledge to train a truly aggressive dog. And the trainers who would, charged a lot of money. Money in which we could not afford that type of training! Fear aggression would have been easier to deal with. I have had a few rescues. Most had fear aggression, which was corrected. This particular dog showed clear signs of not only dominance, but true dog to dog aggression. Be careful of who you adopt your dog from! When deciding on a dog, ask a ton of questions. Our dog also was scheduled for a total hip replacement just a week after the incident took place! So he also had major health issues which in turn can cause aggression. I also wanted to add, that from what I saw at the dog park, I tried contacting his owners to find out why they lied and more about his history. Surprise, surprise they never responded! Then I called the animal shelter where they supposedly got him from… I know from experiences that animal shelters where I live, consider dogs who are aggressive un-adoptable. Sad, because some are simple just acting on fear. I called them, they had no record of him anywhere in being in an animal shelter!!! I miss my dog dearly as he was a different dog around JUST US at the house, but sometimes the most humane thing you can do is euthanize as there are so many great dogs out there, who may have minor issues that need homes.

  8. Linda says

    My problem is dog/dog aggression its that my 13 yr old lab that has grown up with cats has become very aggressive towards them, grumpy & growls if the just walk by. She had snapped & gone bite them on a few occations & just recently has done the same thing to me. Is she just getting old, or is there a problem? I have my 8 mo granddaughter living with me & can not take any chances

  9. Maggie says

    We have 3 dogs – 13 year old maltepoo- Ginger, 7 year old black Lab Enzo – big lump of
    love and slobber, and a 4 year old mix – lab and pit (i was told) – Ziggy, she is a girl.
    I adopted her when she was 9 weeks old from a shelter.
    She has never been aggressive with people but she started getting aggressive
    towards other dogs… especially smaller ones for some reason.

    She is seems especially aggressive when we are in the close vicinity of our home
    and wham I am around.
    I say that because we have a dog walker who takes the
    two big dogs for walks and hikes 3 times a week and she said she has never had a problem with Ziggy! She is generally a sweet girl, was even very lovely with my nephew when he was visiting – he was 20 months old.

    Tonight – when the walker came to drop the dogs off at our home she had them both on the leash getting out of the car and a man was walking a small poodle close to our home and Ziggy pulled so hard the clasp gave out and she pounced on the poor thing!

    I was not told about the scare but not that the dog was hurt, the dog walker left, after
    only telling me this happened and that she grabbed her by her collar.

    However 30 minutes later, I received a SCREAMING HYSTERICAL call from the wife of the man who was calling from the Vet asking about the breed of my dog,
    screaming at me that I don’t control my aggressive dog etc etc. IT was traumatizing!

    This has happened now with me and close to our home 3 times. Once 2 years ago and now 2 times within 2 months… I am petrified.
    I worry for other dogs and about Ziggy. I don’t want her to get into bigger trouble.

    NOT sure how to deal with her. Is there a way to train her to be better behaved or stop
    this aggression?
    PLEASE HELP! Thank you so much

  10. beatty123 says

    Since it sounds like this is a change in behavior, a visit to your veterinarian for an exam is indicated for your dog. This type of new aggression can be a result of pain, sensory changes, or other physical problems.

  11. beatty123 says

    Yes, there are certainly ways to help your dog with this behavior and to manage situations to prevent incidents. But aggression isn’t something we can work on without hands on sessions with the dog. Find a qualified behavior consultant or trainer in your area who uses scientifically sound techniques that do not involve the use of force, fear, or pain. Veterinary behaviorist, Certified Applied Animal Behaviorist, Certified Canine Behavior Consultant or Certified Professional Dog Trainer are good qualifications to look for.

  12. Jessjab says

    Hi there, I have a 2 year old terrier mix that I adopted from a rescue about 3 months ago. He displays a lack of social skills with other dogs and can be quite rude. He gets up and over top of them (t position?) and also stalks. He usually does better with dogs bigger than him but recently he has started to run along side them and bite at their faces. This makes other dog owners uncomfortable because I’m sure they’re scared that their dog is going to snap back and then because my dog is smaller it will turn out bad. Should I continue to take him out to dog parks and let the dogs sort it out? Just as an FYI He is “leash reactive” and really really really wants to get to any dog he sees out on walks as fast as he can. Thanks for any suggestions you may have!

  13. Tori says

    My 1yr old boxer/border collie mix is great with people and puppies, but sometimes at the dog park, if a dog or two starts barking too loudly, she’ll single a dog out and wrestle it down. She never bites, but she barks and snarls and keeps then pinned down. She’ll also do this to some dogs when they try to take her Frisbee. But some dogs she’ll play tug with..I’m thrown.

  14. Judy says

    Our 14 month old shepherd/akita/mutt uses barking to bully. She will play with dogs, and on occasion when a playmate will get tired of playing and try to quit, she doesn’t ‘get it’ and will bark relentlessly.
    I have no idea how to curb the behavior. Generally I walk away (and she’ll follow me). It would be nice to not feel like you have the “rude” dog.

  15. ciro says

    My 8 year old tea cup Yorke bites my 2 year old pitbull and he just let’s it happen knowing it’s not gunna hurt him and that she is much younger should I do something about this

  16. says

    I have a black lab beagle mix. I’ve had him for a little over a year. He’s a great dog never bite anyone and loves other dogs. So I decided to get a puppy. Mainly to keep my lab busy while I can cook/clean etc. But I’ve noticed that my lab growls at the new puppy (not in a playful way). For example. The new puppy was sleeping on his bed my lab walked by and started growling and barking. My lab will not come close to me or my fiance if the puppy is close. Can someone give me some advice on what to do. I love my dogs very much, and I do not know how to get my lab warmed up to our new dog.

  17. Teri says

    Hi, I rehomed a Ridgeback cross Staffie at 7 months old, she’s now 2. I have 2 kids of 9 and 12 years. She wasn’t socialised as a pup – left out in the garden all day alone and tied in the hallway in the evening and at night. She was brought up with a young boisterous child. She is reactive on the lead to dogs and now recently people. Pulling me, up on her hind legs barking aggressively etc. Also, recently she has snapped at my kids in the house while they were playing with her and myself for trying to clip her nails. She’s wary of some people in or out of the house and growls. I can’t trust her around kids that visit the house. She plays off lead very dominantly – rushes up to them (we can’t stop her from taking chase) then is very dominant in her stance and play, if the dog shows aggression she will respond. My concern is for my children, I don’t want them bitten (kids don’t read dog language very well – even though I do my best to not leave them alone with her), it’s become stressful in the house keeping them separated and supervised. It’s also stressful on walks, trying to avoid everyone, even though I try my best not to transfer that stress down the lead and don’t pull on the lead etc. I’m currently trying to find her a new home without kids, with someone that can work on her reactivity positively but as you can imagine, that’s practically impossible. I’ve contacted all the dog rescue centres that rehabilitate but none are taking dogs in. I feel my only option is the unthinkable (pts), which is something I don’t want to do and can’t face doing but we’re so stressed about it all. Any advise please. I’m based in the UK and can’t afford a one-to-one behaviourist and don’t have the time to dedicate each day to training and walking her seperately from my other small dog and my family, many thanks

  18. beatty123 says

    I would strongly advise you to consult with a local trainer or behaviorist experienced in using a scientific process called counter-conditioning to help your lab feel more comfortable with the puppy. This type of situation can escalate to aggression between the dogs. Using positive reinforcement rather than force is key in helping your lab see the puppy as a good thing rather than something to fear or dislike. Be sure your lab continues to get lots of positive attention from you and isn’t pushed aside because of the new puppy.

  19. beatty123 says

    I’m so sorry to hear that your dog had such a poor start in life and you are now feeling she is unsafe in your home. Unfortunately, it sounds like the situation in the UK is similar to the US – the rescues who will take dogs with serious behavior problems are full don’t have the resources take more dogs like this. Finding a new home for a dog who may be a danger to people and other dogs is extremely difficult. When owners don’t have the resources to hire professionals to help with difficult behavior issues, or the time to do training and management of difficult dogs, there are few options left. Prevention of behavior issues like these through proper early socialization, and working with a professional when behavior problems fist appear are vital to having a behaviorally healthy dog. You tried to help, but apparently have adopted a dog you do not have the time or resources to deal with. This is a very sad situation that occurs all too often when people want to save a dog without understanding what it may take to do so. There are no easy answers in a case like this. Changing difficult behavior takes knowledge, effort, time and often money.

  20. Laura Brook says

    Hi i have a rescue beagle x springer spanieland she had a bad upbringing for the first 6 months. We have had her for about 8 months now and Bella is roughly 18 months old. Bella is such a friendly energenic beautiful dog. She loves to play with other dogs and she is a very rough when off the lead always wants to be the one pinning the other down. But recently she has been playing with other dogs and then i dont know if its when shes had enough or not sure about the dog she barks horribly at the other dogs to warn them and doesnt want to stop. Hope this makes sense. Thank you

  21. says

    I have a 4lb 8 yr old Yorkie and a beagle bulldog mix she’s 3 months old. The puppy is quite bigger than my yorkie and the puppy is constantly jumping on the yorkie. She had her pinned in a corner the yorkie couldn’t get out. How do I stop this? Please help me!!!!!

  22. beatty123 says

    Managing your puppy’s interactions with your very small dog is important. Keep the puppy on leash and supervise play. Set up places the yorkie can get away from the puppy, like under a baby gate where the puppy can’t follow. The puppy is being a puppy and the yorkie isn’t large enough to take control and defend herself the way the puppy’s mother dog might. Don’t put your yorkie in a position where she feels she has to bite to survive against a much larger puppy.

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