Interdog Aggression: Why Dogs Fight With Other Dogs

Anyone who has ever witnessed the horrifying experience of interdog aggression and seeing their dog attacking another dog knows all too well the terror of the moment. Interdog aggression is displayed towards other dogs and not toward people. Even though the dog displaying interdog aggression may be acting out of a sense of territorial protection, the owners of the “offender” are plagued with many conflicting emotions as a result of their dog’s “crime.” On one hand you, the dog owner, feel angry at your dog for attacking the other dog that you want to punish your dog. However, on the other hand, you might feel sad or guilty because you realize your dog was only trying to protect you. At all times, it is a nightmare to live through for both you and the dogs involved.

interdog aggression


Stop Interdog Aggression:

* Your dog growls at other dogs, nearby. Growling indicates your dog’s desire to attack.

* Instead of eating a treat immediately upon receiving it, your dog is overly possessive of the treat and hides it or stands guard over the treat so that other dogs or pets won’t take it away. This is also a form of antagonism that your dog is displaying toward your other pets which is another way of saying: your dog is picking a fight.

* What started out as usual playing among your dog and another dog, turns into a hostile fight or growling match. If your dog is not aggressive, they will submit and not growl back.

Risk Factors Associated With Interdog Aggression:

* Fear of being attacked by the other dog, though there may be no indication of aggression made by the other dog.

* Insecurity. Your dog’s insecurity is different than a human’s insecurity: If your dog doesn’t spend his days burning off energy hunting and chasing vermin in the yard or critters in the forest and doesn’t have a good foundation of obedience training and socialization, (s)he doesn’t have the self-confidence necessary to know how to have a balanced relationship with another dog, or how to act when one on one with another animal. This lack of experience causes to insecurity which turns into aggression. Note: allowing your dog to hunt in the woods or in your yard is not suggested to solve insecurity. A professional dog trainer or professionally-advised handling tips must be used to strengthen your dog’s sense of self so (s)he won’t have to resort to violence against every dog encountered.

* Your dog’s natural sense of being territorial. Protecting your home and property might not be behavior that you want to change. If your dog is aggressive towards other dogs that come near your home but is not aggressive when away from your home, you’ll need to make sure that your yard is well-fenced. Also, for some flock guardian breeds, this behavior is encouraged.

* Suffering from previous owner’s over-socialization with older dogs, as a puppy. If you have a rescue dog that is displaying strong dog aggression, chances are high your dog was not socialized properly. (S)he has learned to defend themselves with violent means. If you are an owner of a rescue dog, you probably don’t need to be told that you should start your dog on a “Nothing In Life Is Free” program and begin obedience training exercises so that your dog develops a vocabulary and relationship with you, that will allow you to communicate with your dog that fighting with other dogs is not tolerated.

* Some breeds are more prone to this form of aggression. For some dogs, there may be a genetic component to the aggression.

* Dogs that are often bred to fight are certainly more susceptible to fighting. Dogs like Pit Bulls, Bulldogs, Bull Terriers, Akitas and Shar peis come from a long line of fighters. They have the thrill of the fight in their blood and though they are not natural hunters or have not been abused as puppies, they may (but not always) have a natural instinct to fight with other dogs.

Signs Of Aggression Between Dogs

* While walking on a leash, your dog sees another dog and makes every attempt to wiggle out of his leash in order to attack another dog.

* When you open your front door, your dog tries desperately to run out to attack another dog.

* At the dog park, your dog starts out playing with another dog but begins to fight physically with that other dog over a toy, bone or area of the park.

Stop Interdog Aggression

* Choose a leash and a training collar. Learn the right technique to teach your dog to walk on a loose leash. This can be learned in less than an hour, and for some dogs… in less than 10 minutes. If your dog is not pulling on the leash, there is a 90% chance he won’t be aggressive toward other dogs.

* Hold the leash by putting your thumb through the loop, and then folding the leash in half and close your fist around both strands of the leash. Do not simply grasp the ring of your dog’s leash to hold on to him/her. This is the number one way a dog gets lost. If your dog is prone to running, bring your other hand up under your first hand (two hands, together) which gives you firmer control of the leash.

* Break in the use of a muzzle on your dog, before you encounter another dog.

Note: never force your dog to wear the muzzle for longer than five or ten minutes the first several times. A muzzle can be a stressful experience for your dog.

The first five or six uses of the muzzle, only keep it on your dog for ten minutes and keep your dog inside. Reward them with a treat upon removing the muzzle. After the sixth use of the muzzle, venture outside with your leashed dog and only keep him or her out for 20 minutes maximum. Increase accordingly.

Let me reiterate that interdog aggression (more commonly known as just “dog aggression”) is distinct from “handler aggression” in that the dog is aggressive toward other dogs, and this behavior may be completely devoid of handler aggression.  In other words: Sometimes we’ll see dogs that are perfectly fine around adults, children, babies … even other types of animals.  But when it comes to interactions with other dogs, you’ll see the aggression come out.


Interdog Aggression – What Are The Warning Signs?

In all cases, there will be physical signs– although sometimes subtle– of the aggression, before the dog acts.  This may include:

  1. Stiff and rigid body language.
  2. Pulling the mouth closed tightly.
  3. The dog may lock his gaze with the other dog.
  4. Curling of the upper lip.
  5. Lowering the head (in a stalking/hunting-like position)
  6. Dominant body language or seeking to be physically in a higher position than the other dog.
  7. Hackles up
  8. Lips curled tightly against the teeth, and showing of the teeth.

Types of Interdog Aggression

Interdog aggression can be broken down into the same main subcategories that every other type of dog aggression can be categorized in, namely:

  • Dominant aggression
  • Fear aggression or defensive aggression
  • Territorial aggression
  • Protective aggression (usually of puppies)
  • Pain response aggression

Of course, there are others, but most will fit within one of the above mentioned categories.

Eva writes: “You are so right, Adam! My German Shepherd experienced the same thing and at 2 years of age he became interdog aggressive. I have had 11 “Dog Trainers” and the last one finally told me to have the dog focus on me when other dogs approach. He is doing ok with only one or two other dogs while focusing but when 4 or more dogs come at him he loses it and attacks. I can only walk him with a shock color and, when I see other dogs approaching, ( tough to see them when they come from behind), have to put a muzzle on. I have to be on a constant lookout for other dogs and had a very stressful life with him for the past 6 years, he is now 8.
Sincerely, Eva”

Catherine adds: “I don’t know if you’ll see this reply, but my dog is a great example of your description of how interdog aggression gets started. Maya is a german shepherd/blue heeler mix and was very friendly as a pup. When she was about 9 mos. old and we were out for a walk, a neighbor’s dogs came after us. This happened a few times that summer, then again the next summer. Although they never bit her or us (my husband and I carried pepper spray and a baton to protect ourselves), we could see it dawning on her that “a good offense is the best defense.”

By the middle of Maya’s 2nd summer (when she was almost 2 years old) — and after talking to these neighbors and then finally reporting them to the dog control officer — the neighbors finally got their dogs under control. However, Maya had become a snarling, aggressive dog that was very difficult to control, even with other quiet, friendly dogs…and it had carried over to people.

It has taken me 3+ years of working with her with a prong collar and an e-collar so that she is no longer challenging and showing aggression to the neighborhood dogs. Sometimes we even walk with them and their owners. She is also better with people but still fearful. So, we still have a ways to go — and it’s all because we were attacked by those dogs when she was young.

The funny thing is, when I take her other places, Maya shows little interest in other dogs and is never aggressive towards them. In fact, her behavior in obedience classes as well as a class for becoming a therapy dog was better than anything I ever hoped for — even when other dogs misbehaved or were aggressive, she was fine. We now visit the skilled care section of a nursing home as a registered therapy dog team, and she is fine with the residents in wheelchairs, walkers, and other equipment…as well as the elderly miniature poodle that has the run of the place. She also seems to enjoy children. However, she’s still afraid of standing adults who can get around on their own. I continue to work with her on that fear, taking her to town or other situations with people for socialization at least once a week. — Catherine Seebald”

Philis writes, “Interesting article about interdog agression vis a vis socialization.How about an instance where a 4 year german shepherd, neutered and pack leader of 3 females and 1 male with whom he has been close to and best buddies unto the male turned 2 (he is intact) and the shepherd has now attacked him severely three times and the dog who was attacked is now living temporarily with me and my 2 females. Philis Raskind

Working with a dog that displays interdog aggression can be dangerous.  If you’re at all afraid of your dog, then by all means contact a professional dog trainer.   You might also want to take a look at my book, “Secrets of a Professional Dog Trainer!” and all of the accompanying bonuses that can help you get inside your dog’s head and teach him/her to stop the interdog aggression, as soon as possible.

Her Dogs Previously Got Along… Now They Show Dog Aggression. Here’s What To Do

Skipdogwalker wrote to me about how to handle dog aggression:

Hi: I have 3 dogs (Kona, male pit mix 3 yrs old) (Sur, male pit mix 18 months old) (Sierra, female boxer 7 yrs old) all spayed and neutered. Kona was the first dog… we have had him since he was about 6 months old.

Sierra came next and has been with us for over a year and gets along with everyone.

Sur came last has been with us about 6 months, he had a severe case of mange when we got him but it is now cleared up.

Dog Aggression Over A Kong Toy

Kona and Sur played together, slept together, ate together everyday until last month when they showed dog aggression over a kong toy ($1200.00 at the vet) we now have to crate them and bring them out separately in shifts. We let them out in the house together but they are now always on leashes. They have still fought 2 more times but not as long as the first fight (I was home alone for the first fight and it took me a while to separate them) They are both back to the “nothing in life is free” method. They both wear prong collars and Kona has been trained a little with the e collar. Every time we feel like they are making progress we get a little overconfident thinking/hoping they get along and they go at it again. Any suggestions would be appreciated. Also my wife and I have been married for two weeks and this is not making life easy! Thanks

Adam replies:

Hi, Skipdogwalker:

Congratulations on your nuptials!

dog aggression
dog aggression

As you know, there are several aspects to dog aggression: dominant aggression, fear aggression, territorial aggression and all kinds of other facets of aggressive dog behavior, such as predatory aggression in dogs, aggressive barking, reactivity, etc… And without seeing what’s going on, I can only give you a “best guess” as to what’s going on in this specific case.

The best case scenario is that you can get them to be around each other, but they won’t ever be able to interact with each other– because: They’re both males and they’ve already demonstrated that they are unsafe around each other.

What I would do is either:

1. Find one another home.


2. Get absolute, solid obedience on both dogs, so that they respond to voice commands PERFECTLY … specifically, the “No!” command (which you can use to break them up immediately, should a fight start).

But realize that it’s an explosive situation that you’re always going to need to be “on top” of, 100% of time. I’d definitely get a crate, and alternate which dog is allowed free time. Otherwise, having to constantly supervise the situation will drive you crazy. Of course, both dogs knowing sold down-stay commands will help make life easier. But you’re still in a situation where you’re living under the dog aggression equivalent of the sword of Damocles.

She’s Dog Aggressive, Are You Sure You Want Her?

What if the dog you’re considering might be dog aggressive?  That didn’t stop dog trainer Lynn Stockwell from adopting Clara– who turned out to be a wonderful companion.

Lynn explains:

It’s been made painfully aware to me that I haven’t updated people here as to my recent acquisitions (well, there’s one important item, the rest are just details) and activities. There pictures in here, most of which I’ve tried to resize so as to be more user-friendly to slower internet connections, so be advised if the page loads a little slower.

She’s Dog Aggressive, Are You Sure You Want Her?

Clara, a Boxer cross, came home to live with me back in March 2012, and even before she stepped foot into my apartment she was learning about life with me–or re-learning about life, in her specific case.

See, Clara was picked up as a stray not far, relatively speaking, from where I am living now. The county shelter is the main reservoir for dogs for the local veterinary technician school, and despite the repeated warnings that “She’s dog aggressive, are you SURE you want her?”, the people on the Teacher Dog Choosing Committee had enough faith to bring her to the school along with 2 other lucky pups.

At school, she spent slightly over 2 years living in a kennel environment teaching us students how to perform physical exams, perform anesthesia safely, do dental and catheterization (both intravenous and urinary) procedures, position for radiographs and locate veins for blood pulls. For anesthesia, she was a bit of a booger and needed the Heavy Drugs because of a lost bite inhibition with the main pre-med. With radiographs, she was a pro and pretty much only needed to know what was being radiographed and in what position, and there she stayed with no complaint until the picture was taken. For the venipuncture, her pipes pretty much announced themselves with neon lights, and woe to any student who had trouble locating them.

dog aggressive
Dog aggressive?

First picture I took of Clara at school

I actually fell in love with the dog before I met her. The professor announced the new crop of dogs that filled in the voids left from those adopted out, and mentioned in passing that one of them was “dog aggressive and probably a pit mix.” That was it, and I knew this dog was somehow destined to be a significant part of my life. Not that I go looking for dog aggressive dogs by any means, but her friendliness toward people more than made up for her issues with the other dogs.

Said issues originally seemed to be geared more toward other bitches, which did raise red flags as my parents’ dog is a bitch and they would have to at least peacefully co-exist with heavy supervision if this was to work out. However, her radar did ping on some of the dogs, particularly one of the major dorks who put up a bit of a “I’m all that” front. Observations over the time she was there determined that gender didn’t seem to play a role so much as the individual dog did. I had since put my name on her card as a potential adopter, and so far I hadn’t seen anything so concerning as to convince me to remove my hat from that ring.

They also seemed more fear-based than anything, out of a need for control and the “best defense is a good offense” mindset. This was work-with-able. The whole 2 years she was there, her issues were managed through the use of a popular brand of headcollar as well as mandatory social isolation from other dogs, the latter of which actually helped her to some extent. It didn’t prevent dogs from making googly-eyes and nasty faces at each other, but it kept full-on attacks to a minimum (unfortunately, it also kept positive play interactions to a minimum too, for those who actually played nice in the sandbox).

During quarters when I was interning off-campus, the staff allowed me to come in on the odd weekend day to spend a few hours with Clara as kennels were cleaned and student rotated through other dogs. I was allowed to take off the headcollar and spoil her with chews during this time, as long as I kept her away from the other dogs and students. This continued after my graduation, and we finally arranged a day and time for Clara Freedom Day after a tooth extraction surgery, necessitated by an aggressive cage-chewing habit that snapped off a lower canine and effectively blunted her incisors to the resemblance of small nubbies.

I originally planned to socialize her and help her learn how to be a dog again after 2 years of being a kennel animal, but I couldn’t have been more off in my thinking. Her training began a few days later, after she had caught up on 2 years’ lost sleep from the noisy kennel environment.

This was pretty much the extent of her activity aside from regular walks and potty breaks.

Without going into detail, my “dog aggressive pit mix” passed her Canine Good Citizen test 4 months after bringing her home in March after some intensive obedience training. We were actually ready for it much earlier, but the test was being offered on a certain day, so we waited and continued to work.

See, It’s Hard To Be Dog Aggressive When…

My worries about Clara getting along with other dogs was alleviated when I found the perfect dog around which to put her: Mallory. (I also wish Zeke were around too, as I know he would have been a great teacher as well.)

See, it’s hard to be dog aggressive and put up a front when the other dog just doesn’t care. Well, in Clara’s case it was easy, which made working with the aggression all the easier because she had no REASON to be afraid, as Mallory just rolled her eyes at That Evil Step-Sister and went on with life. Constant visits have whittled away the Best Offense action, setting the stage for one of my favorite pictures of them both, just below. As we’ve progressed, Clara is now trustworthy off-leash around Mallory, and enjoys running around the unfenced yard, which is considerably more space than what we have here. Although there is no interactive play, there is the ability to parallel play–that is, play alongside each other with separate toys, no quarreling and no interaction, which is quite voluntary on the part of both dogs.

Of course, the Master at work in this picture prefers to not use a leash. She in fact gave me quite the nasty look when I suggested she put it in her mouth. That’s not a smile in those eyes!

I spent countless hours building ball drive in a dog that already had one heck of a retrieving instinct, despite having almost no retriever in her. She is an amazing jumper and can get some considerable air when going after her ball. In addition, she’s been introduced to the family farm and the vast amount of space one has to run after the ball. She has it rough, and often comes home and crashes after such days regardless of who’s around!

A happy retrieve

Flying between the trees–a lucky shot on my part!

“Er, Clara…I think we’ve been caught!”
“Yep, just…don’t…move…”

She was working off-leash shortly before passing her CGC. All things considered, not that impressive. I’ve worked a dog that could have passed the test after 3 weeks of work (from SCRATCH too, no obedience background at all!) if only I’d had him tested, and I’ve worked a dog who passed in 6 weeks. I felt it more appropriate to work both obedience and target the aggression issue as well as socialize to life on the “outside,” and combining the 3 goals meant that a 3- or 6-week CGC pass was out of the question. It was the right move for all involved.

As for how she did in a home environment after 2 years in a kennel and no knowledge of her prior background, suffice it to say that someone socialized this dog. I ran the sweeper and she fell asleep with it in the same room (well, that’s unavoidable due to my place being a studio apartment). She hardly bats an eye at the train horns going on at all hours not a quarter-mile from the house. Loud cars, music, TV, construction sights/sounds…no reaction. She passed the Home Depot test, complete with carts, screaming children, lumber equipment and aisle displays, with flying colors. We’re still working on firecrackers and gunshots, but so far things are going well. My housemates absolutely love her, she’s become a fixture around the community due to our frequent walks, and now that Ohio law has changed, the pit bull side of her (well, if there ever was one, based on looks alone) is legal!

Yes, there are some who would brand her mostly pit, but thankfully most see Boxer first

Right now we’re in the polishing phase for obedience, as I’ve slacked off considerably and there are some specific areas in which we need to work. I’m unsure at this point if I want to push more for competitive obedience, or if I want to start her in soft-mouth retrieval and eventual tracking. She’s provided me with lots of good experience, and mistakes have been made on both our parts throughout the process. She’s also very photogenic, especially since her new leather collar got here! Hopefully will be updating a little more frequently and getting back to your regular thought-provoking/critica-thinking programming, now that the cat’s out of the bag concerning this awesome girl.

Purple-on-black leather collar

A nice moment with Mallory and some special effects

Here’s Clara, enjoying the freedom of the big yard and life on the “outside” despite originally being labeled as dog aggressive.

Misunderstandings About Dominance In Dogs

Adam goes on a rant about common misunderstandings about dominance in dogs and how some prominent dog trainers are espousing views on dominant dog training without having a deep enough understanding about the nature of relationship-based training as it relates to dominance.

From the lecture:

Dominance In Dogs

dominance in dogs
Dominance in dogs
free mini-lecture below

Today we’re going to be talking about dominant dogs. Specifically, we were listening to a lecture given by a fairly prominent dog trainer in the sport dog community, who, I have a lot of respect for. I haven’t met him. But apparently he is a very good sport dog trainer.

But he gave a lecture on dominant dogs and aggression and I have some issues that I completely disagree with and thought I would share them with you, today.

Starting out: This dog trainer mentions in his lecture he mentions that some dogs are extremely pain sensitive and– in the process of being asked to do something– they show aggression. But… it’s not that they’re dominant. This is just a super pain sensitive response, like: Some dogs that if you step on their foot, they’ll bite you. That’s not dominance, that’s pain sensitivity.

Totally reactive.

And he goes on to say that you can correct them all you want for that but you’re not going to make them stop biting.

Not Dominance In Dogs But Rather Reactivity? Oh Really?

Folks, this is plainly, flatly, completely… not true.  I’ve been working with dogs for over 20 years now.  You can fix this type of behavior.  There are many dogs that are reactive in the sense that if you step on their foot… they will try to bite you, because: They see themselves as being dominant to you.

Listen to the full audio of this program– a free (five minute) audio mini lecture about dominance in dogs–  below:

Listen to my my free (five minute) audio mini lecture about dominance in dogs by clicking on the play button on the youtube video, above.

See Dominant Little Dog Correct Other Dog For Unwanted Behavior

In this video, “Shorty” is giving the Golden Retriever a “correction” for getting too close to his bone. You’ll notice that the correction was quick and to-the-point. It’s not personal. It’s just enough to get his point across. Look at the expression on the Golden Retriever — he’s not sulking. His feelings aren’t hurt. It’s just a form of communication. In the future, Shorty will be able to accomplish the same, with nothing more than a firm “look” or a glance.