Training and Socializing Dog-Aggressive Dogs

If your dog attacks other dogs, or just really doesn't like other dogs, the good news is that aggressive dog training techniques can help you and your dog.


Editor’s Note: Twenty years ago, people freely used the term “aggressive dog” to describe what, today, we would call a “dog with aggressive behaviors.” The problem with the term “aggressive dog” is that very few dogs are aggressive all the time – and if they are, they are unlikely to be in anyone’s home. Most dogs who display aggression in some situations are loving and loved dogs in other circumstances; calling them “aggressive dogs” overlooks the fact that they are terrific dogs most of the time. Throughout this article, we may use the older, more familiar term, and we will add the modern term that more accurately describes a dog who sometimes displays aggressive behaviors. 

Going for a walk with your dog may be one of your favorite ways to exercise and relax, but your pleasant outing can quickly turn into a stressful one if your dog reacts badly to other dogs and you happen to encounter one running loose. If the other dog is threatening or if you have an aggressive dog (a dog with aggressive behaviors), a dog fight could ensue, and the situation can become downright dangerous.

Like most owners of antisocial dogs, Thea McCue of Austin, Texas, is well aware of how quickly an outdoor activity with her dog can stop being fun. Wurley, her 14-month-old Lab mix, is a happy, energetic dog who loves to swim and go running on the hike-bike trails around their home. But when he’s on-leash, he barks at other dogs, growls, and even lunges.

Because Wurley is 22 inches tall and weighs 60 pounds, he can be hard to handle, says McCue. “When he pounced on one little 10-pound puppy, it was embarrassing for me and scary for the puppy and the puppy’s owner!” Indeed, introducing a puppy to a dog-aggressive dog may be one of the scariest experiences a dog owner can have!

Why Are Some Dogs So Hostile Toward Other Dogs?

If, like Wurley, your dog is reactive to other dogs, you are far from alone. Tense encounters between dogs are not unusual, as dogs who don’t get along with other dogs now seem close to outnumbering those who do. In fact, dog-on-dog aggression is one of the most common behavior problems that owners, breeders, trainers, shelter staff, and rescue volunteers must deal with. So what to do with an aggressive dog (a dog who is aggressive toward other dogs)?

The major reason why dogs become aggressive toward other dogs, says Dr. Ian Dunbar, founder of the Association of Professional Dog Trainers (APDT), is that during their puppyhood, dogs are often deprived of adequate socialization with other good-natured dogs. As a result, many pups grow up with poor social skills, unable to “read” other dogs and exchange subtle communication signals with them.

Regular contact with playmates is necessary for dogs to develop social confidence. The popularity of puppy classes can be traced to Dunbar’s pioneering efforts to provide puppies with a way to experience this vital contact with one another. If puppies miss out on these positive socialization experiences, they are more at risk of developing fear-based provocative behaviors. Because dogs who show aggressive tendencies tend to be kept more isolated than their socially savvy counterparts, their anti-social behavior tends to intensify as they get older.

How to Train an Aggressive Dog

Fortunately, there is a way out of this dilemma. If your dog attacks other dogs, or just really doesn’t like other dogs, the good news is that new dog training techniques are being developed that can help you change your dog’s association and aggressive response to other dogs. Like McCue, who opted to take Wurley to “Growl” classes, you may find these training remedies can improve your dog’s manners so that you can feel comfortable handling him in public again.

Although the techniques themselves may be new, Jean Donaldson, author of Culture Clash and founder/principal instructor for the Academy for Dog Trainers, says that they are solidly grounded in behavioral science theory and the “laws of learning.” Though different trainers design their own classes differently, in general, “Growl” classes are geared to teach dogs to associate other dogs with positive things, and to teach dogs that good behavior in the presence of other dogs will be rewarded.

The first method commonly used in dog aggression training classes involves simple classical conditioning—the dog learns that the presence of another dog predicts a food treat, much as Pavlov’s dogs learned to associate the sound of a bell with dinner coming.

Operant conditioning is also used to teach the dog that his own actions can earn positive reinforcement in the form of treats, praise, and play. Both types of conditioning attempt to change the underlying emotional that leads to aggression in dogs, rather than just suppressing the outward symptoms with punishment.

Outdated Ways of Socializing Dogs

This approach is a departure from the past; only a few years ago, most trainers recommended “correcting” (punishing) lunging and barking with a swift, hard leash “pop” (yank). Although this forceful method can interrupt an aggressive outburst, it seldom produces any lasting improvement—and it does nothing to change the way the dog will “feel” or react the next time he sees another dog.

In fact, this sort of punishment often exacerbates the problem by sending the wrong message to the dog; he learns that proximity to other dogs brings about punishment from the owner! This can stress him more and cause him to behave even more aggressively. Teaching him to anticipate scolding whenever another dog is nearby is not how to calm an aggressive dog (a dog who displays aggression at other dogs).

Punishment results in additional negative side effects. A dog who has been punished, just like a person who has been physically or verbally rebuked, usually experiences physiological stress reactions that make it harder for him to calm down. Also, when a dog growls at other dogs or shows signs of unease and is punished, the dog may simply learn to suppress his growling and visual signals of discomfort; the result can be a dog who suddenly strikes out with no warning.

These are some of the reasons that behavior professionals like Dunbar and Donaldson now believe that it is absolutely necessary to eliminate all punishment and reprimands when dealing with a dog who is aggressive to other dogs

Training an Aggressive Dog: 4 Components of an Effective Program

In the most effective aggression-retraining programs, unpleasant or punishing training methods (“aversives”) are strictly avoided. Among other things, trainers who work with aggressive dogs (dogs with challenging aggressive behaviors) will often use a “Say Please” program. The basic premise is that the dog responds to an obedience cue in order to earn freedoms and privileges. These include meals, treats, toys, play, games, walks, and even attention and petting. The goal is to teach the dog to offer polite behaviors in order to obtain good things in his life.

Meanwhile, the first step in specifically dealing with the dog’s aggression might merely be rewarding the dog for any behavior that does not involve fighting or aggression. His behavior is then modified through a planned program of:

  • shaping (reinforcing each small action the dog makes toward the desired goal);
  • desensitization (presenting other dogs at sufficient distance so that an aggressive reaction is not elicited, then gradually decreasing the distance);
  • counter-conditioning (pairing the presence of other dogs with pleasant things);
  • training the dog to offer behaviors on cue that are incompatible with aggression. 

An example of the latter would be short-circuiting a dog from lunging by having him instead do an incompatible behavior (such as a “sit-stay”) while watching the handler. Eventually, the dog can even be trained to offer this behavior automatically upon sighting another dog. (“If I turn and look at my handler when I see a dog, I’ll get a sardine—yum!”)

Another cornerstone technique, originally developed by behavior counselor William Campbell, is commonly known as the “Jolly Routine.” An owner is taught to use her own mood to influence her dog’s mood—when your dog is tense, instead of scolding, laugh and giggle him out of it.

This same technique can work on fearful dogs. Make a list of items, words, and expressions that hold happy meanings for your dog and use them to help elicit mood changes. “The best ‘double punch’ is to jolly, and then deliver food treats,” says Donaldson. “The bonus to this technique is that it also stops the owner from delivering that tense, warning tone: ‘Be ni-ice!’ ”

How to Socialize an Aggressive Dog

The “Open Bar” is one exercise that might be considered an offshoot of the jolly routine, and it, too, makes use of classical conditioning. Here’s how it works:

For a set period of time (weeks or months, as needed), whenever another dog appears, like clockwork you offer your own dog sweet baby talk or cheery “jolly talk” and a special favorite food never given at any other time. The “bar opening” is contingent only on the presence of other dogs; therefore the bar opens no matter how  appropriately or inappropriately your own dog behaves. Likewise, the “bar” closes the moment the other dogs leave – you stop the happy talk and stop feeding the treats.

Skeptics may ask whether giving treats to a dog whose behavior is still far from angelic does not actually reward undesirable behavior. But behavior professionals explain that the classical conditioning effect–creating a strong positive association with other dogs–is so powerful that it overrides any possible reinforcement of undesirable behavior that may initially occur. The unwanted behavior soon fades in intensity.

Another advantage of the Open Bar technique is that it can be incorporated into training protocols that are easy to set up, such as “street passes.” Street passes are also a means of using distance and repetition to desensitize your dog to other dogs. The final goal is for your dog to be able to walk by a new dog and do well on the first pass.

All you need to set up a training session using street passes is the help of a buddy and her dog. Position yourself about 50 yards from a place where you can hold your dog on leash, or tie him securely to a lamp post or tree. Ideally, this should be on a street, about 50 yards from a corner, so your friend can pass through an area of your dog’s vision and then disappear.

Your friend and her dog should wait out of sight until you are in position and ready with your treats. At that point she should appear with her dog, strolling across an area within your dog’s sight. As soon as she and her dog appear, open the bar and start sweet-talking your dog as you give him treats. The moment that your buddy and her dog disappear from sight, the bar closes and you stop the treats and attention.

If your dog “goes off” (goes over threshold) when your friend appears with her dog, you are too close. Increase the distance and try again, until your dog can stay reasonably calm and take treats when your friend appears with her dog. Counter-conditioning works best if you can keep your dog below threshold, and very gradually decrease distance as you are successful.

Similar sessions can be set up in quiet parks or out-of-the-way places:

With your dog on leash, stand several feet off a path (or farther, if necessary to keep him below threshold), as your friend walks by with her dog, also on leash. Both dogs should have an appetite (don’t work on this right after your dog has been fed!) and you and your friend need to have really yummy treats in hand to help keep your dogs’ attention on you and to reward them for good behavior.

Have your friend walk by with her dog. If your dog is able to maintain a sit without lunging or barking, repeat multiple times. (If your dog is over threshold, increase the distance between you and your friend and try again.) As training progresses, you will gradually reduce the distance necessary for your dog to react calmly with what Donaldson calls an “Oh, you again” response when the familiar dog passes by. Repeat the same process as new dogs are introduced into the equation.

Growl Classes

Naturally, the more dogs that your dog can interact with, the better chance he will improve his behavior. If the dog has bite inhibition (when he does bite another dog, the bites are not hard enough to break the skin of his victim), Donaldson believes the ideal solution is a play group of “bulletproof dogs” who are friendly, confident, and experienced enough to interact well with him. Unfortunately, this kind of play group is not easy for most owners to replicate on an as-needed basis.

Donaldson says the second-best thing is a well-run “growly dog class” just for aggressive dogs (dogs with aggressive behaviors). One way these classes differ from regular training classes is that everyone in them is in the same boat, and therefore willing to work together to overcome their dogs’ behavior challenges.

One of the most comprehensive programs is offered by the Marin Humane Society in Novato, California. Training director Trish King says MHS’s “Difficult Dog” class size is limited to eight dogs and progress proceeds in baby steps.

“The first class is very controlled,” she describes. “We’ve prepared a small fenced area (using show ring gating) for each dog and the first couple of weeks we throw towels over the fences to prevent the dogs from making eye contact. By week three, the coverings have been removed. By the fourth week we have a few dogs in muzzles wandering around each other. The goal is to have the dogs remain under control when another dog runs up to them!”

King says that proper equipment is part of the formula for success. Dogs are acclimated to wearing Gentle Leaders (head halters) for on-leash work and muzzles for off-leash work. Since muzzles can interfere with the dogs’ ability to pant, care must be taken not to let dogs become overheated while using them. No pinch collars or choke chains are allowed.

“We’ve found that most people have already tried to use corrective collars, and they haven’t worked,” says King, “probably because of the lack of timing on the owners’ part, as well as the fact that these collars can set the dog up for identifying other dogs as a threat; they see an oncoming dog, while they feel the pain of the collar jerk, and they hear their owner yelling at them.”

Changing this common scenario begins with teaching owners to keep the leash short but loose. Instead of punishing corrections, MHS instructors use a variety of exercises to train dogs to avoid conflicts.

“We teach dogs to follow their owners, not to pull on leash, to watch the owner, sit, down, stay, and so on,” says King. “We also teach the owners how to massage their dogs, and how to stay calm and in control at all times. More than anything else, the class is to help owners control and manage their dogs.”

Changing the Dog Handler’s Behavior to Manage Aggression

Across the continent in Toronto, Canada, Cheryl Smith, who developed some of the concepts used at MHS, also believes that working with owners and dogs as a team is one of the most important components of her Growl Classes. One of the first things that Smith teaches owners is how to take a deep breath and relax about everything. Owners who remain calm are better able to pay attention to their dog’s body language and to observe what triggers aggression.

Without special coaching, owners are likely to do exactly the opposite, thus making the problems worse.

For example, if you anticipate or respond to your dog’s aggressive behavior by tightening up on his leash, you will reinforce his perception that he should be leery of other dogs. If you get upset when he lunges and barks, your emotions will fuel his tension and aggression. If you continue to punish and reprimand your dog after he has started to settle down, you will only confuse him and make him more stressed, because punishment that comes more than a couple of seconds after a behavior is too late – your dog will think he is being punished for being quiet!

In contrast, the right approach utilizes prevention and early intervention. The dog must be prevented from repeating the problem behavior because every time that he does so successfully it will become more entrenched! Interventions may include moving to break eye contact, using a body block to prevent physical contact or to redirect forward movement, walking away quickly with the dog, giving a cue such as “Gentle” (open the mouth and relax the jaw) or “Off” (back away), and offering treats to defuse or interrupt tension interactions. 

Dogs Learn at Their Own Pace

Of course, there will be some dogs who don’t respond adequately to any dog-aggression training program. These may require a referral to a certified veterinary behaviorist who can prescribe appropriate behavior medications as part of the treatment arsenal. If you have an aggressive dog (a dog with aggressive behaviors), you have a responsibility to ensure his safety and that of others by taking appropriate measures, including the use of a muzzle when indicated.

But no matter how serious your dog’s problem may be, Jean Donaldson advises keeping it in perspective:

“In any discussion of aggression, it bears remembering that the bar we hold up for dogs is one we would consider ridiculous for any other animal, including ourselves. We want no species-normal aggressive behavior directed at any other human or canine at any time, of even the most ritualized sort, over the entire life of the animal? It’s like me saying to you, ‘Hey, get yourself a therapist who will fix you so that for the rest of your life, you never once lose your temper, say something you later regret to a loved one, swear at another driver in traffic, or yell at anyone, including your dog.’ It’s a tall order!”

In other words, keep your expectations realistic. Then, if you stick with the program, the odds are you will end up pleased with the results, like Thea McCue. After completing their Growl Class course with trainer Susan Smith, owner of Raising Canine in Austin, she and Wurley are once more able to hit the hike and bike trails together again. Describing Wurley’s progress thus far, McCue says, “he warms up to other dogs much faster and rarely reacts to dogs while we’re running.” Although there remains room for improvement, Wurley’s days of pouncing on puppies are over!



  1. Can I put a new dog with a aggressive dog because I am looking at getting a nother dog and was wondering if I can put a nother dog with 7 years old dog that has not been around other dogs

    • my dog is aggressive towards other dogs and we just got a new puppy so i would recommend taking them both on a walk on separate leashes separate people and just have your old dog on leash where ever it is your going on a walk (i wouldn’t do in your yard maybe across the street or something for territorial reasons) and just completely ignore the new dog because if you ignore the other dog your dog will as well and just continue on your walk as if there is no new dog and if its going well SLOWLY get closer to the other dog w/o getting to close and stop a few times along the way and just take a drink or something casual and then keep going if your dog shows aggression on the walk turn him around have him sit and pet him and just calm him down this may take a few walk the walk is also a good way to know whether or not your dog is going to show aggression

  2. I have a rescue dog – he’s been with our family one week now. He’s been great so far when socializing with other dogs at the dog park. He has walked away when other dogs have shown aggression. He has shown some leash aggression, which has not been too troubling, because I can easily work with him on this. Today we went to the dog beach and he suddenly became outwardly aggressive to two separate dogs while off the leash. He listened to verbal commands initially, but the second time I had to physically separate him, and he lunged for me. He was surrendered by his previous family after being with them for five years. He’s a beagle mix, but I’m not sure what he’s mixed with – either boxer or pit bull. I’m not sure how well he was socialized by his previous family, or the type of training he had, but I’m not sure if the root cause of his sudden aggression today. It’s not consistent with how he’s behaved. Any suggestions?

    • I am having similar issues with a pit bull German shorthair mix (rescue)- he is normal not that interested in other people or dogs but has a few good playmates he gets along well with and has known since he was a pup- but lately duke (55 solid lbs) has been getting more aggressive he will be playing fine then the other dog grabs the toy or ball and he gets very aggressive- I’m not sure how to respond I was afraid to reach in an take the ball away

      • We had a Rottweiler for a few weeks that we fostered with no background. I had hesitations about taking the ball,toy, away from her as well since I didn’t know her at all. So, I offered her treats in exchange for fetching the toy. A treat trade for releasing the item and retrieval. She couldn’t be happier with fetching and releasing. I trained my now, German Shepherd Malinois mix with this same concept. They learn quickly and food motivates me too!

  3. We are sponsoring a 10 year old poodle/shihtzu for one week. Would like to adopt the dog. He is wonderful with people, unruffled by thunder, loud noises. Not aggressive or interested in our pet birds and hamsters. However, he is very aggressive toward other dogs. When we walk him he goes crazy when he sees other dogs– barking,growling etc. According to the shelter he was raised with a “brother” that was adopted separately. They said the pair were not “very bonded”. The owner was elderly and could no longer take care of the dogs. He is so easy in the house, totally trained, barks to indicate he needs to be walked. How can we socialize an old dog ? Is it possible at his age?

  4. Hi. I fostered a dog for about 6weeks. He was so good we fell in love and adopted him .. he was great with people. No reaction to other dogs . Listened very well. Upon adopting he needed to be nuetered. One week or so after being nuetered he went on his normal walk. A dog ran up to him. Snarled and basically grabbed my dog and gave him a bloody nose. My dog did react to a certain point He didn’t injure the other dog. Exactly 4days later this happened again with another dog while on a walk. But when the other dog ran up. My dog grabbed him real good and was shaking him back and fourth terribly. Now I cannot walk my dog. When he sees a dog while in my car going for a ride he’s like the devil. What can I do?

    • Adding to the above comment, you wouldn’t even believe the level of aggression she has towards other dogs unless you saw it with your own eyes . the hair along her entire back is up, if any dog is within sight, she is barking, pulling , you can tell that she isn’t capable of even thinking of anything else. This also happens even if it’s not a dog, but she thinks it’s a dog (someone walking with a bag or pushing a wagon for example) I know for 100% fact that she would absolutely kill any dog she got a hold of , without a second thought. I’ve had SEVERAL altercations with strangers over the years, I’m on a first name basis with bylaw , and the humane society enforcement task force (yes, that exists) have been to my house more than once to issue warnings and investigate complaints. I have even had an eviction notice for not muzzling her (fought- and won -that illegally issued and unauthorized scare tactic) although she’s never actually had the opportunity to do anything and never will.

  5. A 60 lb aggressive dog is hard to control? LOL. Try 130lb…. when you are a female, 5 feet tall , no more than 150 lbs, and live in an area that is HIGHLY populated with little pugs and chihuahuas , aka her favorite kind of snack!

    And I have done this for 6 years ! Even through the pregnancy,birth, and first 2 years of a childs life.

    But seriously…this is by far the best, most informative, actually helpful information I have come across yet. And believe me, I have searched done my due diligence and put in countless hours of searching . Thank you!!

  6. About time I found a good article on this thing we call the internet. My dog is so great in every aspect of a well behaved pup, except when she meets a dog for the first time. Her hair goes up, growls, snarls, and will lung at the other dog. It’s heartbreaking, since my wife and I adopted her at 8 weeks old and used to go to dog parks on a daily basis. She has had many many doggy friends and Positive playdates.

    She has never had issues with other dogs until she turned about 2 years old. I feel like it’s my Poor temperament that she feels herself. I get anxious and worry that she will react mean, When we see a dog on a walk, thus introducing her mean behavioral issues.

    I wonder if I should pay for a dog trainer or attempt to train her myself. It’s so frustrating that I have to “ train “ her all over again after how much time, training, love , affection and overall support/comfort my wife and I have gave her throughout our time with her.

    Thanks guys

  7. I thought that we were doing everything right. We took our pup to the dog park and dog daycare to socialize him. He was initially the park greeter and loved to play with all the dogs. From his foster homes he had learned proper dog etiquette and would always give his butt to be sniffed. Then he was attacked at the dog park by a dog guarding her tennis ball. We continued to take him to the park and day care but he became anxious. One day he pinned a puppy (basically sat on him). After doing this a couple of times I decided to keep him away from the park. He seems to want to play with other dogs that we meet on walks. He still gives his butt to be sniffed but then after a couple of seconds he gets a look on his face that lets us know that he’s had enough. He snaps at these dogs (never making contact) and we leave. I don’t know if his behavior will continue to escalate. I know he needs some playtime with other dogs but we are afraid because his behavior can be inconsistent. Is there anywhere in southwestern michigan that trains with these strategies?

    • Thank you for the advice in this article.
      My now 3 year old Aussie has steadily gotten aggressive towards some dogs and even dogs she has met before since 2 and half years old. She was a total love bug before but has become very protective of the dog group and buddies she hangs out with. We go to off leash dog park and every now and then she will target one particular dog snarling and chasing it to the ground (no biting). It’s upsetting to me and obviously to the other dogs owner. I’m keeping her on Halter for most of the time and watching behavior. Don’t understand why she is so moody!

  8. Thank you for this article it is always go to read about different training methods.
    I have a small rescue and dog aggression is a serious issue, and makes it very hard to re home these dogs.
    We need more tools to help these dogs as many end up being euthanized. Rescues have a harder time housing these dogs and often people think a dog that is aggressive with dogs will be aggressive with people which is often not the case at all.
    One thing I would like dog owners to learn is that it is their responsibility to socialize their puppies while they are young.
    More importantly is that they need to know how to do it CORRECTLY.
    DO NOT just let your dog socialize with unknown dogs, dog parks are a horrible way to to this. Often the dogs there are too wound up and have bad manners. It is better to set up a play date with a known balanced dog. An older tolerant dog can be a great teacher and provide a safe introduction and appropriate correction when your dog is impolite.
    so in general it is as important who you select for your dog to socialize with as it is to socialize your dog.

  9. I am taking care of my sons Australian Sheppard who is about 8 years old. He is fine with me and children. And my 3 dogs but when my fiancé tries to go outside he barks and growls at my fiancé. And very aggressive. He is an outside dog. So my fiancé as to have me around in order for him to do anything in the yard. What can I do to help him get used to my fiancé

  10. I adopted a rescue on March 1st. He’s an adorable poodle (possibly terrier) mix. We bonded very quickly. He is sweet and cuddly with me. The problem is I can’t have ANYONE over or he goes crazy. He barks and lunges and nipped at a male friend a couple weeks ago. He definitely does not like men but will also bark at my daughter when she comes over too. Not as aggressively but I can’t have him nipping at people.
    Now that we are all staying home due to the Corona virus I’m afraid it’s going to get worse since he’s not seeing anyone but me.
    I’m nervous to take him on walks in the neighborhood because I don’t know how he’ll behave. When he hears any noise outside he barks. When he is in that “mode” he won’t take any treats from me. I try the “jolly” talk and tell him he’s OK. But he doesn’t hear anything. I am open to any advice or tips. Thank you.

  11. i have i 6 year old female dog who wasn’t very socialized when she was young she had a litter of puppies and even raised a second littler hat wasn’t hers she showed aggression towards the mom but she seems to show aggression towards dogs bigger then her but not to much towards puppies but she still growls and barks. i just got a puppy andt hey are fine on leash walking but once they sniff each other she growls and barks she never bitten me or anyone or any dog before so it is not really bad but she still growls at the puppy. any suggestions?

  12. Thank you so much for this article! I stumbled on it when our humble, loving dog had an aggressive response to a person familiar to our household. We did a complete vet physical and found out he had a double ear infection, but no one is certain what prompted the aggression. The open bar worked like magic. We could see him visibly relaxing as the training progressed. This saved us and him from unpleasant and unproductive training methods. Thank you!