It's important to have realistic expectations when introducing a new pet to a resident pet. Some cats are more social than other cats. For example, an eight-year-old cat that has never been around other animals may never learn to share her territory (and her people) with other pets in the household. However, an eight-week-old kitten separated from her mom and littermates for the first time, might prefer to have a cat or dog companion. Cats are territorial and need to be introduced to other animals very slowly in order to give them time to get used to each other before there is a face-to-face confrontation. Slow introductions help prevent fearful and aggressive problems from developing. PLEASE NOTE: When you introduce pets to each other, one of them may send "play" signals which can be misinterpreted by the other pet. If those signals are interpreted as aggression by one animal, then you should handle the situation as "aggressive."
Confinement Confine your new cat to one medium-sized room with her litter box, food, water and a bed. Feed your resident pets and the newcomer on each side of the door to this room. This will help all of them to associate something enjoyable (eating!) with each other's smells. Don't put the food so close to the door that the animals are too upset by each other's presence to eat. Gradually move the dishes closer to the door until your pets can eat calmly, directly on either side of the door. Next, use two doorstops to prop open the door just enough to allow the animals to see each other, and repeat the whole process.
Swap Scents Switch sleeping blankets or beds between your new cat and your resident animals so they have a chance to become accustomed to each other's scent. Rub a towel on one animal and put it underneath the food dish of another animal. You should do this with each animal in the house.
Switch Living Areas Once your new cat is using her litter box and eating regularly while confined, let her have free time in the house while confining your other animals to the new cat's room. This switch provides another way for the animals to experience each other's scents without a face-to-face meeting. It also allows the newcomer to become familiar with her new surroundings without being frightened by the other animals.
Avoid Fearful And Aggressive Meetings Avoid any interactions between your pets that result in either fearful or aggressive behavior. If these responses are allowed to become a habit, they can be difficult to change. It's better to introduce your pets to each other so gradually that neither animal becomes afraid or aggressive. You can expect mild forms of these behaviors, but don't give them the opportunity to intensify. If either animal becomes fearful or aggressive, separate them, and start over with the introduction process in a series of very small, gradual steps, as outlined above.
Precautions If one of your pets has a medical problem or is injured, this could stall the introduction process. Check with your veterinarian to be sure that all of your pets are healthy. You'll also want to have at least one litter box per cat, and you'll probably need to clean all of the litter boxes more frequently.
