Are You and Your Current Dog Ready?

Before bringing a second dog home:

• Follow the 3-3-3 Rule, to ensure your current dog has had enough time to adjust and decompress. Make sure you have had your current dog for longer than three months, and they are acclimated, comfortable and relaxed at home. (For more information, check out: Adopting: The Rule of 3s.)
• Assess your resident dog(s). Before bringing a new dog home, assess whether or not this will enrich your current dog’s life and increase their overall quality of life. If your dog has not been able to live comfortably with other animals in the past — due to their behavior, tolerance threshold or sociability — getting a second dog could be challenging, stressful and even detrimental to your current dog's emotional well-being. 
• Is your resident dog healthy and happy? Consider taking your current dog to the vet to make sure they are not experiencing any medical issues, contagious illnesses or physical pain. If your current dog is dealing with any of these things, they are likely experiencing heightened stress and are more susceptible to trigger stacking (For more information, check out: Trigger Stacking & Stress Hormones and Stressed Out: How You Can Tell and What You Can Do About It). Bring in another pet only if your current dog is healthy and their behavioral and emotional needs are being met. 
• Do you have the appropriate set up? When introducing dogs in the home, you may need to separate them at times if they are getting annoyed with each other, frustrated, over aroused, or playing too rough. Consider getting exercise pens, baby gates or dog play pens to use as barriers when you need to give them space away from each other. Additionally, animal introductions take time, supervision and patience. Are you (or other family members) able to supervise all interactions between the two dogs for the first few months? Are you willing and able to take on training if the two dogs aren't comfortable with each other right away or if new behavior challenges arise? For more information, see the "Preparation" section below.

Your dog may be a good candidate for having a roommate, if:

• Your dog has successfully shared space with (lived with) other dogs, in the past. 
• Your dog is generally social, tolerant and "friendly" with other dogs (see this article on Understanding Dog Sociability). Keep in mind: Some dogs may be social and "friendly" with other dogs, but will not enjoy sharing space with other dogs or cannot successfully live with other dogs. Adversely, some dogs may not enjoy playing with or interacting with other dogs outside of the home, but can successfully live with other dogs. 
• Your dog is generally confident, mellow and easy-going.
• Your dog does not have any current behavior challenges that may be exacerbated by a second dog, including: resource guarding, poor impulse control, increased stress or fearful behavior.
• Your dog does not guard resources (food, bones, treats, toys, beds, people, space, etc.) from other dogs by tensing, freezing, growling, snapping or biting.
• If your dog does show resource guarding behaviors, it's to a degree that is preventable and easily managed.
• Please note: When assessing a pet's behavior and personality, be careful not to assign rigid labels to them. Behavior can change in different contexts. Labels can be helpful when describing and understanding our pets' behavior, but they shouldn't define who your pet is. It's important to keep in mind, an animal's behavior is influenced by their environment. Ask yourself: What is my pet doing and under what conditions? (For more information on why our pets do what they do, check out: How Behavior Works: Learning Theory & Training Methods, How Pets Learn, How Dogs Learn and Why Animals Do What They Do.)

For more things to consider, check out these resources: Introducing Dogs & Cats, Dog Parks: To Go or Not To Go and Adopting A Dog: Getting Ready. 

Finding A Prospective Dog

For additional tips on how to find the right pet for you, check out our Behavior & Training Lecture: Adopting/Transitioning Shelter Pets.

• Behavioral History: Find out as much as you can about the behavioral history of any dog you are considering adopting, specifically in regards to dog sociability, resource guarding and living with other dogs. Ideally, the new dog you plan to bring home will have a history of having lived comfortably with other dogs, without apparent conflict. Avoid adopting a dog that has a history of resource guarding, fights with other dogs, a bite or other harm to another dog or extreme fearfulness (Check out the article, Adopting A Dog: Choosing The Dog For You, for more tips on how to find the right dog for you).
• Consider energy level and play style. Ideally, the new dog's energy levels and play style would be similar to and compatible with your current dog. If your current dog is low energy, sensitive, gentle and/or nervous, look for a dog who appears to also be gentle and relaxed, with low to medium energy levels. Avoid dogs who enjoy rough play, lack impulse control, are easily over aroused or are particularly mouthy, as these traits can be overwhelming, stressful and intimidating for softer, sensitive dogs. Additionally, a sensitive, low-energy dog that is unsure and does not reciprocate play can be frustrating for dogs that seek high-energy, rough play, which can lead to conflict. Consider a dog who engages in soft play or games of chase rather than physical play. If your current dog is high energy, rambunctious and easily over aroused, look for a dog who appears to be outgoing, confident and sturdy, with medium to high energy levels. If a dog is very tolerant or dog social and is not easily frightened or overwhelmed, they may be a good candidate to consider. (For information on appropriate dog play, watch these videos: Learn About Dog Play From Expert and Shelter Playgroup Alliance: "Green," "Yellow" & "Red" Behaviors. Check out our YouTube playlist: Impulse Control, Overstimulation, DSCC & Choice).
• Confidence: Shy or fearful dogs often benefit from living with a more confident and outgoing dog. Sharing space with a confident dog can help a shy dog come out of their shell and feel more comfortable. If your current dog is shy and sensitive, consider adopting a confident, mellow dog and vice versa. If you adopt a shy dog, your confident dog may be able to help them build trust and confidence (For tips on adopting a shy or fearful dog, check out this article: Adopting: Shy or Fearful Dogs).
• Make it easy for your current resident dog. Help your current dog prepare for and adjust to a new dog joining the family by implementing positive reinforcement training and stress-reducing management. If your current dog is shy, nervous or sensitive, consider enrolling in our Shy Dog class to learn how to boost their confidence, read their body language and strengthen your bond. If your current dog struggles with hyperarousal, reactivity or impulse control, consider enrolling in our Reactive Rover: Mat Work class or Control Unleashed: Foundations class. Start practicing Calm Behavior At Home and Troubleshooting Behavior Challenges, so you and your dog have the skills needed for coping with an increase of stress that can come with of introducing dogs.
• Sociable and well-socialized: Look for a dog who is either tolerant of or social towards other dogs — sociability is a spectrum (see infographic: Dog Sociability is a Spectrum). Additionally, look for a dog who has been socialized to other dogs at an early age. If a dog wasn’t socialized to other dogs at a young age, they may not show appropriate, relaxed or “neutral” behaviors toward other dogs as an adult. Furthermore, if a dog has had a negative experience with another dog in the past, they are more likely to have a negative association with other dogs. (For socialization tips, check out our YouTube playlist: Well-Socialized Pet Resources. Enroll in all 6 of our free Well-Socialized Pet Chats held live online over Zoom.)
• Slow introductions! Regardless of whether you have information about a dog’s history or sociability or you’re bringing home a puppy, you’ll want to gradually introduce your current pet(s) to your new pet. It's important to go at your pets' pace to avoid rushing the introductions. Many dogs are unsure of other dogs at first, but with time can become more comfortable. Read your dogs' body language, listen to their stress signals and pay attention to their comfort levels.

Preparation

• Success Stations for the Dogs: Before bringing home the new dog, set up at least one success station. A success station is a dog-proofed area where one of your dogs can relax and entertain themselves when they are unsupervised or becoming over aroused. These can be helpful for managing the excitement and/or stress that can come with meeting a new dog roommate.This should be a play pen, dog-proof room, or an area of the home blocked off with baby gates or exercise pens. A success station should have everything your dog needs: Food (if it's mealtime), water, place(s) to rest and sleep, potty pads or access to a potty area, and toys and enrichment to keep them entertained. There shouldn't be anything in this area that you don't want your dog to potentially chew on, destroy, or soil. A success station sets your dog up for success because it offers appropriate options for your dog to make good choices — your dog can stand up, walk around, play with toys or sleep. Furthermore, a success station can be a good place for the new dog to relax unsupervised if they have not learned the potty routine and other rules of the house yet. It will keep the dog contained, preventing them from getting into mischief, while providing a safe place for them to decompress and enjoy alone time while they are still getting used to the new home and family. The success station can be utilized during the introduction process, as well. If one of your dogs is coming on too strong, getting overly excited or overwhelming the other dog, you can put them in their success station to cool down and give the other dog a break. You should introduce your dogs to a Calm Settle behavior, that can be practiced and strengthened in the time leading up to the introduction process. During each stage of the introduction you can ask for a calm settle, because some dogs need help relaxing in the presence of exciting things. This skill can also help your dogs relax in their success station (For more information on how to set up a success station and train your dog to be comfortable in one, check out: Dog/Puppy Pen Set Up and Train Your Dog/Puppy to be Calm in a Pen.) 
• Plan Ahead: Create a plan for when the new dog arrives home. It's best to introduce dogs in a "neutral space" outside of the home. Pick a location for the introduction and enlist someone to help you handle one of the dogs. Dog introductions require at least two people, one handler for each dog. For more recommendations, see the "Dog to Dog Introductions" section below. After the initial introduction, consider bringing the resident dog to their success station or away in another room, before bringing the new dog inside the home. This will allow the new dog to start settling in the new space without the presence of the other dog and prevent them from being immediately bombarded by the resident dog as soon as they enter the home. Offer the resident dog a chew, bone or other form of enrichment to help them relax and stay busy, while you are busy with the new dog. Once your resident dog is contained and occupied, bring your new straight to their potty spot, so they have an opportunity to go potty and can start learning their new potty routine early. Allow them to sniff, explore and familiarize themselves with their new environment, before allowing the resident dog to come out. It's best to keep the dogs separate for bedtime the first night, to allow them to decompress and calm down away from each other. 

Dog Body Language

Dogs communicate with us and each other through body language and behavior. Dogs will display a range of behaviors that indicate whether or not they are comfortable with an interaction or situation. Ideally, the two dogs would appropriately communicate with each other and "listen" to each other, but this is not always the case. It is important to supervise and be ready to step in if a dog interaction escalates. Some dogs ignore communication signals or lack the skills needed to play appropriately due to missing out on socialization when they were a puppy. Other dogs may inappropriately "correct" another dog, or "overcorrect" them, which can be perceived as harsh or taken badly by the other dog, lead to an escalation or negative interaction.

You can better understand what your dogs are feeling during an interaction by observing their ears, tails, eyes, mouths, bodies and fur. Ask yourself: Are my dog's ears perked forward or pulled back? Is their tail hanging loose, tucked between their legs or up high and stiff? Is their tail wagging big and loose, small and fast, or low and slow? Are their eyes soft and relaxed or wide and alert? Is their body crouched and stiff or relaxed and wiggly? Is their fur flat or puffed up (piloerection)? All these questions can help you notice and identify your dog's body language.

From there, you can interpret these signals to determine what they are trying to communicate. It is important to understand your dogs' signals and make sure they are listening to each other and respecting their boundaries, so they don't feel the need to escalate to "louder" forms of communication (growl, pinning each other down, snapping or fighting). 

Indications that your dog is experiencing relaxation or positive emotions (both are good) include a soft, relaxed face and loose "neutral" body, an open mouth (not panting or drooling), a loose "happy" wagging tail and choosing other behaviors while in the presence of the other pet, such as checking in with people, sitting or lying down, looking away from the other pet and sniffing or moving away. (Important note: A wagging tail indicates general arousal, it does not necessarily mean they are "happy." To learn more about interpreting a tail wag, check out: What's in a Wag.) 

In positive dog interactions and appropriate dog play, both dogs need to be feeling comfortable and enthusiastic about the experience. If only one of the dogs is enjoying the play, while the other is being avoidant, trying to escape or showing signs of stress, human intervention may be necessary to redirect the more enthusiastic dog away from the uninterested dog before things escalate. 

Indications that your dog is experiencing stress, fear, hyperarousal, reactivity, frustration or other negative emotions include turning away from the other dog or moving away from the other dog, "fiddle behaviors" or displacement behaviors (yawn, lip lick, shake off, sniffing, or scratching out of context ), a stiff and alert body, tense facial muscles, a tightly closed mouth, panting or drooling, spatulate tongue (Check out: Spatulate Tongue - Dog Body Language), a high and stiff tail with tight very quick "stress" wags or a low, tucked tail, and being unable to break focus from the other dog (fixation). Other stress signals and behaviors include straining and pulling at the end of a leash, whining, barking, growling, lunging, snapping, biting, hard stare and fixation (intent focus), puffed up tail and fur (piloerection) and apparent agitation. These are all signs that a dog is not feeling calm or comfortable interacting and may not be able interact appropriately with the other dog. The goal is relaxed body language, enthusiasm to play or interact and indications of positive emotions towards the other dog.

If one or both of the dogs are not comfortable and enthusiastic about the interaction, redirect the dogs away from each other, initiate a break and separate them so they can cool down and decompress. 

To learn more about body language signals, check out: Reading Body Language YouTube playlist and Stress in Pets: What To Look For.

Dog to Dog Leash Introductions

The introductory period can take weeks of brief, supervised interactions after the initial introduction to get to the point of calm interactions and peaceful coexistence. Observe both dogs' body language and behavior to gauge how they are feeling about interactions and their new roommate in general. For an in-depth presentation on body language, check out: Behavior & Training Lecture: Can You Speak Dog or Cat? 

1. Become familiar with the nuances of dog body language and appropriate dog play. More on this in the "Red, Yellow & Green: What to Look for and What to expect" section below.
2. It's best to do dog interactions when both dogs are relaxed and have had an opportunity to burn mental and physical energy earlier in the day. Before the dog introduction, burn some of your dogs' energy through a sniff walk, interactive play, a training session, brain games, foraging or another form of mental enrichment, to promote calm behavior.
3. Begin with both dogs leashed, with separate handlers in a “neutral” space such as a park or a walk in the neighborhood, to prevent your resident dog from feeling threatened by another dog unexpectedly entering “their space.” 
4. Each handler should have high-value treats on them for rewarding calm behaviors, redirecting the dogs if they are fixated on each other, and luring the dogs AWAY from each other to increase the distance between the dogs. Important: To prevent resource guarding, DO NOT offer dogs treats or have treats visible and within their reach when the dogs are interacting or closer than 15 feet to each other. DO NOT use treats to lure the dogs towards each other or to pressure them to interact. For more information, check out: Social Pressure & Animal Interactions and What is Resource Guarding?
5. Find a comfortable distance between both dogs, where they can observe one another without becoming reactive and/or aren’t pulling together to greet. This distance should be roughly 25-30 feet, but this depends on the dogs. For some dogs, you will need to start much farther away. 
6. Try to keep the leashes loose, to prevent leash pressure than can contribute to your dog feeling restricted, stressed or frustrated. You can use treats to work on loose leash walking, lure the dog to walk next to you rather than pulling ahead, and redirect them if they are straining or lunging at the end of the leash. For more tips, check out: Success on Leash and Training Tips: Loose Leash Walking. 
7. Go for a walk! While still maintaining a distance, take turns letting one dog trail the other to gather information (smells from the scent glands between paw pads left on the ground or excrement). Check out this video on Parallel Walks for an example. Reward the dogs for looking at each other and displaying calm behaviors and relaxed body language. Redirect the dog if they become fixated on the other dog. The goal is for the dogs to feel neutral about the other dog and be able to look AWAY from the other dog, otherwise they are not ready to meet yet. 
8. When both dogs appear relaxed and comfortable or are occupying themselves by sniffing around or looking elsewhere, you may begin to close distance slowly, roughly 5 feet at a time.
9. Each time you close distance, wait for your dogs to “relax” again.
10. Once you are able to walk within 15 feet of each other, with both dogs appearing relaxed and comfortable, you may be ready to have them meet. If either of dogs are fixated on the other or tense, redirect them away and increase the distance between them.
11. Allow the dogs to approach one another with handlers making an effort to move with the dogs in an “arc” or U-shape to avoid approaching directly or in a straight line. Important: Keep the leashes loose! It may to difficult to keep the leashes loose as the dogs first approach each other if they are enthusiastic to greet and pulling on the leash, but once they have reached each other the leashes should be loose. In polite greetings, dogs will move in a circle, taking turns sniffing each other's rear. The handlers should follow the movements of the dogs as to keep the leashes loose and avoid inhibiting their natural movements and greeting behaviors.
12. If at any point during the on-leash greeting the dogs are face-to-face for longer than approximately 2 seconds, redirect them using high-pitched sounds or calling them away from each other.
13. The on-leash greeting should be brief, as dogs don't enjoy greeting or interacting on leash because the leash pressure inhibits their natural movements. So, once they have successfully interacted on leash without any signs of discomfort, quickly but calmly move away creating distance once again and end the on-leash interaction before they begin feeling frustrated by not being able to play or move freely.
14. Allow both dogs to cool down from the excitement of the greeting before initiating an off-leash interaction. 
15. The off-leash greeting should ideally be done in a neutral area as well. Check out Sniff Spot, a way to rent a private "dog park" to allow your dogs to enjoy exploring and playing without the risk of other dogs or people interrupting or adding unnecessary conflict. 

For additional tips, download this Introducing Dogs At Home flyer and watch this B&T Lecture: Introducing New Pets.

A Note on Reactive Dogs

If one or both of the dogs have a known history of dog reactivity on leash, but greets and plays appropriately off-leash, consider modifying your introduction. Furthermore, it's important to observe your dog's body language when they are displaying reactivity, in order to understand your dog's reactivity — whether it is caused by fear or excitement and frustration. Fearful reactive dogs will need slower, shorter interactions. Excited or frustrated reactive dogs may need frequent breaks during play and interactions to avoid over arousal or escalations. Good options for reactive dogs may include:

• A brief leashed intro, only long enough to allow the dogs to quickly greet and sniff each other for a second or two before being redirected and separated.
• An intro with both dogs dragging light leashes that can be grabbed by the handlers if things escalate and tools to interrupt escalating play or disagreements (water from bottle, bowl or hose, spray citronella, or loud non-threatening noises like a clap or air horn). 

Additional resources & training classes for Reactivity:

• Thinking about bringing a reactive dog into your home? Learn more through this short course. 
• B&T Lecture: Reactivity (Management for Reactivity & Potential First Steps) which is part of our YouTube playlist: Sociability, Reactivity, Leash Skills & Play
• Learn about our Reactive Rover series of classes and why we only offer them online.
• Enroll in a Reactive Rover: Mat Work or Reactive Rover: Heel Work class to get started. 

Red, Yellow & Green: What to Look For and What to Expect

Observe your dogs' body language while approaching for red, yellow and green signals during dog-to-dog interactions and play. Green is good, yellow indicates discomfort and possible escalation, and red is to be avoided. Here is a video example of red, yellow and green signals in play.

• If your dogs appear tense, frustrated or become reactive with red or yellow signals, move apart quickly in opposing directions calling your dog in a cheerful voice and/or move behind a visual barrier (block your dog’s view). Calm your dog by having them do something else for a bit, such as smelling around in a new area or eating treats off the ground, and then start over.
• If your dogs are greeting with green and yellow signals or are exchanging play gestures (bowing, mirroring each other, pausing with open mouths, pawing), move to a private, contained space where you can allow your dogs to engage in play with their leashes on (allow light leashes to drag from their collars or harnesses, so each handler can easily grab a leash to separate the dogs if necessary).
• If you are unsure of whether or not your dogs are both actively engaged in play, you can gently pick up the leashes, guiding the dogs apart in opposite directions. Drop the leash of the least active and least confident play participant, and wait to see if this dog approaches and engages the second dog again.
• If the least active play participant does not approach and engage again, redirect the dogs and give them a break. Not engaging in play is often a signal that they are disinterested or uncomfortable engaging.

Preventing Resource Guarding

Resource guarding is a survival instinct that most animals have to some degree, even humans. It occurs when an animal is trying to protect a resource that they deem valuable. A dog that resource guards is NOT trying to be dominant, "alpha," or mean. (For more information on the myth of the "alpha," check out: "Alpha" Wolf? and Is the Alpha Wolf Idea a Myth?) Resource guarding stems from an animal's insecurity that their resources may be taken away or they will not have access to enough resources. There are ways we can help dogs feel more confident about their access to resources, in order to prevent resource guarding in multi-dog households.

• Remember to keep resources (food, bones, treats, toys, beds, people, etc.) separate for both dogs in your home for a minimum of a week. Provide both dogs with their own bed, toys, food and water bowls, and treats or enrichment. Separately provide both dogs with equal amount of human interaction, attention and access to people. Do not expect or force your dogs to share resources. 
• Trade up. If your dog has something they aren't supposed to chew on or play with (shoe, clothing item, TV remote, object, etc.), do not just take it from them. Instead, trade them with something better. Offer them their favorite toy or a delicious treat. Wait for them to willingly drop the object and go for the trade before taking the object from them. This will help them view you as a "giver" rather than a "taker." 
• Provide an abundance of resources, so your dogs do not feel they need to hoard or guard resources due to a scarcity. Provide more than enough toys, multiple of each type. For example, if you have many toys but only one rope toy, there is a chance the dogs could fight over that type of toy if they are both wanting to play with a rope toy. 
• Supervise the dogs when they are playing with toys, to ensure they do not fight over toys. Put away all the toys when you are unable to supervise them. 
• Feed separately. In general, it is good practice to always offer food items or items containing food in completely separate spaces as a preventative measure. Completely separate your dogs during feeding time. It's ideal to feed dog in separate rooms or areas of the home, where they cannot see each other. However, you can also utilize baby gates, ex-pens or furniture to create a barrier between the two dogs as long as the dogs are a fair distance away from each other. Make sure they cannot interact through the barrier, because dogs can resource guard or "fence-fight" through barriers.
• Do not leave food bowls, treats or enrichment out and accessible, even if they are empty. 
• Do not use punishment, force or intimidation to attempt to stop your dogs from resource guarding. This will only make it worse, as it will add to their stress and insecurity. Do not take things away from your dog or out of their mouth, this could result in a bite and cause future resource guarding (For more information, check out: Positive Punishment, Safety: Dog Bite Prevention, and How to Stop Unwanted Behavior Without Intimidation). 

For additional tips and resources, check out: Resource Guarding Resources YouTube Playlist, Behavior Challenges: Resource Guarding, and Resource Guarding in Dogs.

Ask For Help

If, for whatever reason, things are not working out, San Diego Humane Society is here to help. We understand that being a pet parent can be challenging — especially with multiple pets — which is why we offer numerous options and resources for pet parents in need.

If your dogs are not getting along, here are your options:

1. Completely separate the dogs, for safety. Wait a few weeks before trying another introduction. Don't let them interact unsupervised.
2. If your dogs have had an unpleasant interaction, gotten into a fight or are not getting along, they may be experiencing inter-household aggression or resource guarding. For information and tips, check out: Inter-Household Aggression with Michael Shikashio and Managing Aggressive Behavior.
3. If you adopted one or both of your pets from San Diego Humane Society, you are provided with a cost-free, 1-hour Post Adoption Consultation online over Zoom. One of our Community Animal Trainers will help troubleshoot while providing starting points and next steps for you. Book here: Schedule a Post Adoption Consultation.
4. Book an online Private Lesson (1 hour, online over Zoom), for advice and training exercises from one of our Community Animal Trainers. Open to all community members, these sessions focus on environmental management, troubleshooting and training exercises.
5. Behavioral challenges — like inter-household aggression or resource guarding — can be dangerous. We recommend hiring a professional, certified positive reinforcement dog trainer that specializes in resource guarding or inter-household aggression. Find a trainer that can come to your home to assess the situation. Find a trainer here: Local Positive Reinforcement Animal Trainer Directory. For additional help finding a trainer, check out: How To Pick A Trainer 101 and Trainer Danger: How To Find A Trainer Who Won't Harm Your Pet.
6. Consider the well-being and quality of life for all animals and humans involved. If needed, rehome your pet here: Give Up/Rehome A Pet here.