Introducing Your New Dog To Your Family Dogs

Written by Suzanne Hetts, Ph.D., Certified Applied Animal Behaviorist
Denver Dumb Friends League (Humane Society of Denver)

Domestic dogs are social animals. This means that they naturally live together in groups which have social structures called dominance hierarchies. This is sometimes thought of as a "pecking order." Dogs also establish territories which they often defend against entry by intruders or rivals. The territorial and social natures of dogs need to be taken into a account when a new dog is brought into the household.

Territorial Behavior

Choose a neutral location: Introduce the dogs in a neutral location to minimize the chances of the existing dog viewing the newcomer as a territorial intruder. Each dog should be handled by a separate person. With both dogs on a leash, take them to an area such as a park with which neither of them are familiar. If you frequently walk your resident dog in the park several blocks from your house, your dog may View that park as her territory, which would not make it a neutral location. Choose another site. You may want to bring your resident dog with you to the animal shelter or the other adoption location and begin the introduction there,
Use positive reinforcement: From the first meeting, you want both dogs to expect "good things" to happen when they are in each other’s presence. Let the dogs sniff each other, which is normal canine greeting behavior. As they do so, talk happy, friendly tone of voice—"Look at your new friend! What a good dogs you are!" Do not use a threatening tone of voice—"FIDO, BE GOOD, WATCH YOURSELF!!" Do not allow the dogs to investigate and sniff each other for a prolonged time, as sometimes this escalates to an aggressive response. After a short time, get both dogs’ attention and give each dog a tidbit of food in return for obeying a simple command such as "sit." Take the dogs for a walk and let them sniff and investigate each other at intervals. Continue with the "jolly talk," food rewards, and simple commands.
Be aware of body postures: A body posture, which indicates things are going well, is a play-bow. The dog will crouch with his front legs on the ground and his rear in the air. This is an invitation to play, which usually elicits friendly behavior from the other dog. Watch carefully for the body posture, which indicates an aggressive response, may occur. These would include hair standing up on the dog’s back (piloerection), baring teeth, deep growls, a stiff-legged gait, or a prolonged stare. If you see such posture, interrupt the interaction immediately. Don’t do so in a pushing way, but rather calmly and positively get each dog interested in something else. For example, both handlers can call their dogs to them (give a little jerk on the leash if necessary), have them sit or lay down, and reward each with a tidbit. The dog will become interested in and excited about their tidbits, which will prevent the situation from escalating into aggression. Try letting the dogs interact again, but this time for a shorter time period and/or at a greater distance from each other.
Taking the dog home: When the dogs seem to be tolerating each other’s presence without fearful or aggressive response, and the investigating greeting behavior have tapered off, you can take the dogs home. Whether you choose to take them in the same or different vehicles will depend on their size, how well they ride in the car, how trouble free the initial introduction has been, and how many dogs are involved. If you have more than one dog in your household, it may be best to introduce the resident dogs to the new dog one at a time. Two or more resident dogs have a tendency to "gang up" on the newcomer.

Dominance Behavior and Social Structure

Whenever more than one dog lives in a household, the dogs will establish a dominance hierarchy. This social hierarchy is determined by the outcomes of interaction between the dogs. Owners cannot choose which dog they want to be dominant. When a new dog is brought into the family, the hierarchy is upset because the newcomer’s place is unclear.

Who will be dominant: It’s difficult to know ahead of time which dog will ultimately dominate. Individual personality as well as breed characteristics are important factors. Males are usually dominant over females, young adult dogs are usually dominant over puppies and aging dogs, and larger dogs are usually dominant over smaller ones. Initially, the resident dog is likely to be more dominant but this may change, as the new dog becomes more familiar with and comfortable in her surroundings. Remember that these are generalizations that may or may not apply to your dog.

How is dominance established: Dogs usually establish their dominance hierarchies through a series of ritualized behaviors that include body posture and vocalizations, which do not result in injury. One dog may "stand over" another by placing her paws on the shoulders of the other dog, or draping her neck across his shoulders. However because of past experiences, inadequate socialization, or genetic temperament tendencies some dogs instead may, with little warning, escalate dominance displays into aggression. If this occur, contact your veterinarian for more information and for a referral to a professional animal behaviorist who is trained in animal learning theory and ethology.
Support the dominance hierarchy: You need to support whatever dominance hierarchy or "pecking order" the dogs establish for themselves. Don’t undermine the natural hierarchy by attempting to treat the dogs too equally or preventing the dominant dog from asserting her position. Dominant dogs can be and should be allowed to take toys away, to push in to receive attention and petting from the owner, to control favorite sleeping places, toys, and other valuable (from the dog’s point of view) resources. Support the dominant dog’s status by allowing this to occur.
Keep the Routine: Keep the resident dog’s routine as much the same as possible by keeping feeding, exercise, play, and sleeping times and location the same as before the new dog arrived. You can also give each dog sometime alone with you. Perhaps the subordinate dog has a difficult time playing with toys because the dominant dog takes his toys away. Put the dominant dog(s) outside with a chewy while you play with the subordinate dog inside. When structuring these individual sessions, the dogs that are subordinate animals are receiving special attention, which they are not, it may undermine the dominance hierarchy and contribute to a fighting problem.

Introducing Puppies to Adult Dogs

Puppies usually pester adult dogs unmercifully. Before the age of 4 months, puppies may not recognize subtle body postures from adult dogs that are signals they have had enough. Well socialized adult dogs with good temperaments can set limits with puppies with a growl or snarl. These behaviors should be allowed. Adults which are not well socialized or who have a history of fighting with other dogs may attempt to set limits with more aggressive behaviors such as biting which can harm the puppy. For this reason, new puppies should not be left alone with an adult dog until you are confident the puppy is not in any danger. Be sure to give an adult dog some quiet time away from the puppy and perhaps some individual attention as described above.

If the introduction of a new dog to a household does not go smoothly contact an animal behavior specialist immediately. Dogs can be severely injured in fights, and the longer the problem continues the harder it will be to resolve. Conflicts between dogs in the same family can often be resolved with professional help.

Punishment is not the answer.