Introducing a New Dog

Last month we had a canine houseguest. We typically don’t dog sit because we are always über-busy, and it affects Will’s routine, but the dog we were asked to care for while his people enjoyed a vacation is an Australian shepherd, and we couldn’t possible say no to having an Aussie in the house for a little while.
We know the owners well, but only met the pooch, a 2-year-old entire male, a few times, and Will never met him at all. Nevertheless, I was not too worried inviting him into our midst because I know Will, knew how savvy and conscientious the Aussie’s owners are, am experienced with dogs and, surely, anything can work for a temporary period of time with clever management.
My criterion for long-term cohabitation is different. Clever management is not good enough, not fighting isn’t good enough, even dogs just tolerating one another isn’t. In my home, for dogs to permanently live together, they have to genuinely like each other. Can you imagine living with someone you don’t like in close space and for the rest of your life?
Most people want the same I do when they play with the idea of getting another dog. They want everyone to get along and envision their dogs being companions for each other. Hence, I regularly find inquiries how to accomplish that in my inbox. People are unclear if same or opposite gender works better, if the new dog should be close in age and have an alike, or complementary disposition.
Like it is so often the case when it comes to dogs, there is no clear answer. It depends, and that is what I typically email back - and not to drum up business for myself. Who fits best really is an individual thing.
That said, there are some general aspects that increase the probability of peaceful co-existence. For example, it helps if one dog is naturally deferent. Makes sense, doesn’t it? If all dogs are equally confident, no one will back away if there is a resource dispute. Who defers doesn’t matter. I don’t buy into the common belief that the exiting dog must be the alpha – yes, I am aware that alpha is a loaded word; sometimes it is the other way around, but it is essential that the existing dog’s life is not miserable because of the interloper. I don’t mean to sound callous, but I have a “last one in, first one out” rule. My loyalty is with the pooch I have had for many years, and I know how tough it can be letting go, but re-homing is the kinder solution when dogs truly clash.
Obviously, choosing the new dog wisely makes necessary re-homing less likely. Male/male, male/female and female/female combinations can all harmonize wonderfully, but two intact males can have ongoing issues, especially when there is an intact female around who becomes a desired, yet limited resource when she is in heat. Limited resources are a big deal, and big deal things incite potential confrontational reactions. But even that can work with a savvy owner.
Compatibility is more important than gender, and also more important than age. Our 11-year-old Will is snooty and aloof with just about every adult dog, and we thought that a pup she could raise any which way she wants to would be the best match, and yet, she quite liked the Aussie house guest. Methinks because, although Will didn’t know that particularly dog, there were many behaviors that resembled our Aussie Davie’s, who was her companion for 9 years.
He was also quite respectful, yielding to her. He still lives with his mother who obviously taught him manners. And he is very human oriented because his people do a lot of fun stuff with him. He solicited play with Will for sure, but was easily appeased to play with hubby Mike and me instead when Will wasn’t in the mood. I was able to re-motivate him, and therefore he didn’t pester her.

Dogs like Will that are not all that keen on goofing around with other dogs are more common than you might think. Age can play a role, but genetics and the dog’s life experiences during the critical developmental stages are contributing factors. Singleton puppies and ones removed from their mother and littermates too soon are often socially inept and awkward with other dogs; puppies who had to fight for basic needs, food, can view other dogs as rivals and aggress over resources. They can still successfully live with the right other dog, one who isn’t relentlessly space-rude and overbearingly playful.
Conversely, dogs that had littermates, were naturally weaned, and had in general more positive contact with dogs than with humans, will be happiest in a home that includes a dog who equally enjoys the company of his own kind. Sometimes such a dog is actually needed as support for a dog who knows little or nothing how humans function.
Extremes are rare - most dogs straggle the middle having a slight preference for either dogs or humans - but they do exist, and asking questions about the dog’s past living conditions can provide valuable clues if, or if not, he’ll fit nicely into your social group.
Unfortunately such information isn’t always available. All dogs have a history, but often it is either unknown or not revealed, so in reality the only reliable tool a potential owner has is to observe how the desired add-on moves and behaves around other dogs, and how the existing dog and the newbie act around each other.
My favorite way to check that is going for a walk. Whether it is in the existing dog’s neighborhood or on neutral ground depends on the dog. If he is anxious in unknown territory, home ground is better; if he is strutting home ground as if he owned it, neutral ground is better.
Best-case scenario is when both dogs are casually aware of each other, curious without being tensely fixated or frenetically pulling. Ideally, the dogs switch between ogling each other and being interested in other things in the environment. Ideally, each dog can easily be prompted to pay attention to his/her respective handler.
Two weeks before the Aussie guest landed on our doorstep we arranged for a walk in a multiuse off-leash park both dogs were familiar with. The Aussie was aware of Will and came for a sniff, but backed off instantly when Will gave him the “too soon for intimacy” eyeball. Both dogs had no issues moving together in the same direction though, and shared an interesting sniffing spot within the first 10 minutes. Both dogs took treats from the Aussie’s person and me, loosely close in space and patiently waiting their turn. I knew they’d be getting along.

Some humane societies and rescue organizations make it obligatory that all family members, including the canine one, must meet the dog they are thinking of adopting. It is a rule I like. Personally, I would not consider adding on a dog mine hasn’t met, unless I’d have an easy-going pooch who likes everyone.
We all know that real life and ideal doesn’t always link: People don’t know what to look for; get a long-distance dog they’ve never met; inherit a dog; consciously understand that the newbie might not be the best fit but want him anyway or, as it was the case with one of my recent clients, they had always boarded their dogs with a friend when away, but their new acquisition didn’t get along with the friend’s dog. What to do in those cases?
You still want to go for a walk, but you probably have to start from a greater distance to get the casual awareness behavior you are after. Just to clarify, you don’t want complete avoidance, a fixed “watch the owner”, because when dogs ultimately live in the same household they can’t avoid each other. What you do want is a  “There’s an unfamiliar dog – oh well, not a big deal”.
If one of the dogs is deliberately and constantly looking away, or sniffing the ground, he is overwhelmed and you need to decrease pressure by increasing distance.
When you work patiently at the dog’s comfort level, eventually they will become familiar and curious about one another, and at that point you can get closer, and if both dogs stay fluid and can be prompted to reorient to the person, a brief sniff’n’greet can happen. The dogs choose where they want to sniff: head first or anogenital area, but how they do indicates who, if there is a dispute, will likely defer. Although you want to use rewards later on to convince each dog that being near the other is great news, there is no need to add treats to the initial sniff – the dogs being able to gather more information about each other is intrinsically reinforcing.
Keep the initial contact brief, and then increase the distance again, on a loose leash by encouraging the pooch with body and voice to follow. Yo-yo between sniffing and walking away, gradually increasing the time the dogs are close together.
Be animated when you walk away, but don’t use any other reinforcements when cohabitation is the goal. You want to make the best resources available when they peacefully share space, not when they are apart, thereby fostering cooperation.

With some dogs, going for a few walks is all they need to become buddies; with others, you have to meet at different places and more often before you enter home-turf together. Whenever you incorporate a new area, make the other components easier: start from a greater distance and decrease duration of sniffs, and once that new place is familiar, decrease the distance and increase duration again.
Also be aware that animation increases arousal. The dog might be loose and non-reactive when the other does “normal” things: walks, sniffs, looks, but over-reacts when he does something odd. For example, when Will made a snow angel, the Aussie boarder got all excited and was on his way to pounce on her, which without a doubt would have resulted in an argument. Because I was aware of this, I was able to prevent it by re-motivating the Aussie. So, pay attention to that until the dogs are familiar with each other’s idiosyncrasies.
The first time the dogs are together in their home, up the value of reinforcements. They should experience, once again, that the best things manifest when they are sharing space. Life for the existing dog has to stay the same or become better with the arrival of the gatecrasher. Ensure that the familiar routine is kept, that he has access to all places he had before, and that, if he is older, has opportunities to rest and sleep undisturbed. And don’t forget that owner attention is a highly valued resource, so don’t shift your gaze away when the other butts in.  All that seems commonsensical, but I have had clients who suddenly banned the older dog from the bed or a certain part of the house with the new arrival, and then wondered why his behavior changed for the worse.
If a dog is – or feels – put out with the appearance of another, anxiety, animosity and aggression builds.

Alike seeks alike and meshes well - unless they are equally jaded and confrontational. Initially less than perfect matches can still work, if the humans meet each dog’s individual needs, and that can mean a lot of extra time a day that goes to the dogs.
If, or if not, a social group harmonizes depends on the dogs, but also, perhaps more so, on the people’s level of skill and available time; the amount of effort and commitment they are comfortable making.