How to Introduce Dogs When One is Aggressive

Introducing dogs when one exhibits aggressive tendencies requires careful planning, patience, and an understanding of canine behavior. You can take steps toward a safe meeting by controlling the environment, closely monitoring both dogs’ body language, and knowing when to call it quits. 

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How to introduce dogs when one is reactive

Dogs are natural pack animals and can often thrive with canine companionship. Some dogs, however, are highly reactive to other dogs and can exhibit concerning behaviors like lunging, barking, or other forms of aggression. There can be many reasons for this behavior, such as not being used to other dogs or being territorial, but sometimes, dogs just don’t like other dogs. So how do you introduce dogs when one is reactive? We spoke with Dr. Terri Bright, clinical behaviorist and director of the behavior department at the Angell Animal Medical Center in Boston, to get the low-down. 

Bright cautions that a first step before introducing dogs is considering the value added. What is the benefit of introducing these dogs? Oftentimes, dogs who are known to be aggressive toward other dogs should be kept separate; the risk of them hurting another dog — or a human who tries to intervene — is just not worth it. 

If your dog appears to be more reactive than aggressive (i.e., they seem fearful and uncertain about other dogs, and they do not offensively try to bite or attack them), you may decide that it is worth it to try to introduce them to another dog. Knowing both dogs’ histories, there are steps you can take to work toward a safe, successful meeting. 

Choose a neutral territory 

Dogs are naturally territorial, so the first step toward a successful meeting is making sure neither is on their home turf. “You don’t want to have your dog in the backyard at its gate and then open the gate and throw another dog in there. That’s like throwing somebody in a shark pool,” Bright says. 

Find an open space where both dogs can be distanced from one another, such as a field or park. You may want to choose somewhere that is fenced in if the dogs will be off leash.

Begin side-by-side and at a distance

When first introducing dogs when one is aggressive, you should have both dogs on leashes for safety, but you should not approach head-on, with dogs straining at the leash and getting in each other’s faces. Bright recommends parallel walking, with both pet parents walking their dogs in the same direction, staying as far apart as necessary to keep both dogs calm. Incorporate reward-based training by giving the dogs treats when they look at each other.

“Gradually, as they stay relaxed you can lessen the distance between them, always giving them treats when they look at each other,” Bright says. “If they stay relaxed and their body language stays relaxed, then they can sniff noses for two seconds then you call them back, walk five or six feet apart, let them touch noses again.” 

Gradually work up to more interaction

If the parallel walking goes well, both dogs appear to be relaxed and eager to interact, and neither dog is showing signs of aggression, you can attempt to advance to off-leash interaction. Bright advises keeping a leash on the reactive dog and allowing them to drag it on the ground, in case you need to quickly gain control of them again. 

“Just let them interact, sniff around, play, whatever, for two or three minutes, then gather them up again,” Bright says. “You’ll have some idea then how things are going to go. What you’ll see is how they react to each other.”

If the dogs remain calm and you see signs of positive interaction, you can gradually increase the time they are allowed to interact. 

What not to do when introducing dogs

The following are things not to do when introducing dogs. 

• Do not introduce them head-on:  Bright warns that one of the worst things you can do when introducing dogs is introducing them head-on with them staring each other down at the end of their leash. “The face-to-face meeting with two dogs straining on a leash, the dogs are just going to be too aroused,” Bright says. 

• Do not act scared or stressed: Dogs are very attuned to human behavior, and will pick up on it if you are scared or stressed, which can lead them to thinking that the other dog is a threat. 

• Do not meet in one of the dogs’ territories: That dog may become territorial toward the other dog and become aggressive. 

• Do not introduce them in confined spaces: Meeting in a tight space, such as a living room with a lot of furniture, can create additional stress if a dog feels cornered. It can also make it more challenging to separate the dogs if needed. 

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Reading and responding to dog body language

An essential part of introducing dogs is reading and responding to their body language. Body language is one of the major ways that dogs communicate and tell us they’re happy, relaxed, scared, or stressed. Keep a close eye on your dog and learn their positive and negative interaction cues so that you can prevent the interaction from taking a turn for the worse. 

Signs of stress, fear, and aggression 

If you have a reactive dog, you need to be able to recognize body language that signals they are scared, stressed, or becoming aggressive. If you can recognize these signs before your dog is lunging and snapping at the other dog, you can remove them before it escalates to a fight. The following are signs that a dog who is stressed, fearful or aggressive may display: 

• Raised hackles

• Bared teeth 

• Ears up and forward

• Stiff posture 

• Hard staring 

If you notice any of these signs, remove your dog from the situation. When you are ready to try again, back up to parallel walking and positive reinforcement for looking at the other dog calmly. 

Recognizing positive interaction cues 

Positive interaction cues, on the other hand, can serve as a green light that your dog is enjoying the interaction. Bright recommends looking for mirroring behaviors: “What you want to see is what we call reciprocal play, so dogs mirroring each other’s actions. Maybe one dog play bows, the other dog play bows, and then they run counter clockwise around the yard, and then maybe there’s another play bow and then they run clockwise around the yard. If they wrestle, then they take turns being on top.”

She warns that while many people think that a dog rolling on their back and exposing their belly is a sign of submission, it can actually be a signal that they are done playing. 

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How to break dog aggression towards other dogs

Bright cautions against talking about dog behavior in terms of “fixing” a problem. 

“It’s too big a question to say, ‘Can you cure an aggressive dog?’” she says. “It’s just a question of, can you control the environment where the dog is? Can you teach alternative behaviors that are reliable enough so you keep the dog from aggressing in the future?” 

The following are some strategies for managing a dog who is aggressive toward other dogs. 

Reward-based training 

Reward-based training is a positive-training method that involves giving dogs treats or praise when they exhibit the behaviors you want them to do. This conditions dogs over time to associate good vibes (i.e., treats) with listening to you, staying calm and relaxed, and exhibiting other positive behaviors. 

Use reward-based training to teach your dog appropriate behaviors around other dogs. This can include giving them treats when they look toward the other dog without barking or lunging or when they sit quietly by your side in the presence of another dog. 

Kinship always promotes reward-based training over punishment or fear-based training. 

Parallel walking and structured activities 

Interactions between two dogs, when one is aggressive or reactive, should remain supervised and structured. This allows pet parents to maintain control over the situation, compared to unsupervised, off-leash playtime, which can quickly escalate to not-so-playful when one dog is aggressive. 

Activities like parallel walks, or time-limited play sessions can allow parents to continue assessing the situation for signs that their dog is reaching their limit and no longer enjoying the interaction. 

Gradual increase in interaction time and proximity

As with any training regime, it will take time and patience for two dogs to get used to one another. In early interactions, start with small increments. During a parallel walk, let dogs sniff each other for a few seconds before retreating. If you’ve deemed it safe for them to interact off-leash, start with just a few minutes of playing before calling them apart. 

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Household management for multiple dogs

Oftentimes, forced proximity of two dogs who don’t get along happens during the holidays or other gatherings when it is normal for people to bring their pets. To keep these multiple-pet visits calm and controlled, pet parents need to take a few steps, including establishing separate spaces and supervising interactions. 

Establishing separate spaces and resources 

Because dogs can be territorial, shared toys, food and water bowls, and living spaces can start a fight. Designate a room for each dog where they will sleep, eat and drink, and be left alone. This can prevent any territory-driven aggression from occurring. 

Supervised interactions and alone time 

When two dogs are sharing a household and one is aggressive, it is essential that pet parents supervise interactions so they can separate the dogs if necessary. To keep both dogs safe, you should only allow the dogs to interact in controlled environments when both dogs can remain calm. If that means they can only interact during parallel walks, so be it. If that means they can only play outside and not inside, so be it. You know your dog and their triggers best, so you can set them up for success by controlling their environment. 

When one of the dogs is aggressive, it is very likely that the two dogs will never be able to peacefully occupy the same general spaces, and that is OK. Part of being a pet parent is knowing your dog’s limits and behaviors so you can keep them and others safe. 

“You want to make sure that each dog can be successfully segregated in a room by itself, and then you basically rotate the dogs out: OK, it’s Fluffy’s turn. OK, it’s Max’s turn,” Bright says. “If that is not possible … because the dog screams and cries if it’s separated, then maybe one dog needs to be kenneled and doesn’t go for Thanksgiving.”

I can vouch that the rotation is a great solution for household management for multiple dogs. While I would love for my corgi and my brother-in-law’s Australian Shepherd to get along, we’ve had too many scuffles to allow them to interact. It is a lot more peaceful for the whole family when one dog is in the common area while the other has alone time behind a closed door. Every few hours, we rotate the dogs so that they get equal attention from the humans. It’s not ideal, but it’s much better than constantly fearing a dog fight. 

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FAQs:

How to tell the difference between reactivity and aggression in dogs? 

While similar, there is a difference between reactivity and aggression in dogs. Aggression is behavior with the intent to harm, and reactivity is a strong reaction to an external stimulus. For example, a dog who lunges and barks at other dogs and would bite them if unleashed is exhibiting aggression. A dog who has an excessive or intense reaction to a specific stimulus, such as a dog walking by or a person ringing a doorbell — but does not actively try to cause harm — is exhibiting reactive behavior. 

How to stop my dog from humping other dogs? 

One less-than-ideal behavior that dogs may exhibit during an interaction is humping. If one of the dogs is irritated and you need to stop the humping, strategies like redirecting the dog’s attention or leading them away with a leash may be effective.

References:

• Day, Jasey. “Reading Dog Body Language to Socialize Your Dog.” Understanding Dog Body Language When Introducing New Furry Friends Helps with Socialization. Learn Tips on How to Read Canine Postures and Body Language., 8 June 2022, www.akcpetinsurance.com/blog/reading-dogdog-body-language-during-or-before-greetings. Accessed 25 Nov. 2024.‌

• Gardiner, John. “Aggression and Dominance in Dogs.” Animal Health Topics / School of Veterinary Medicine, 20 Mar. 2019, healthtopics.vetmed.ucdavis.edu/health-topics/canine/truth-about-aggression-and-dominance-dogs.

• “Introducing Your New Dog to Your Resident Dog.” Longbeach.gov, 2000, www.longbeach.gov/globalassets/acs/media-library/documents/resources/introducing-dogs. Accessed 25 Nov. 2024.