It’s important to have realistic expectations when wanting to introduce a new cat to other house pets that have lived there for a long time before. For example, an older cat around the age of 8 that has never had to share living space with other animals may never learn to share their territory, and owners with other pets in the household. However, a new, young kitten that has only just been separated from its parents and siblings for the first time might definitely prefer the company of another cat companion.
Cats are naturally quite territorial and need to be introduced to other animals slowly in order to give them time to get used to each other to prevent any face to face confrontation. Slow and patient introductions help to prevent fearful and aggressive problems from developing.
Confinement is one method to help integrate your new cat to its home. Confine your new cat to one medium sized room with her litter box, some food, water and a bed. We recommend ‘cave’ like pet beds as these provide anxious or stressed animals a place to hide away in! Feed your resident pets and new cat on each side of the door to this room, this will help all of them to associate something enjoyable, which is eating in this case, with each other’s scents. Don’t put the food too close to the door that the animals become too upset and stressed 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. The final step to this is to use doorstops, helping to leave the door open just a little so the pets can see each other while eating and keep repeating this process.
Switching sleeping blankets or beds between your new cat and other pets can help each other become accustomed to each other’s scent. Rub a towel on one pet and put it beneath the food dish of another pet so they have another opportunity to become used to each other’s scent while doing something enjoyable.
Once your new kitty is using the litter box and eating regularly while in confinement, give them free time in the house while confining your other pets to the new cat’s allocated room. This switch is a beneficial way for your pets to experience each other’s scents more freely without a direct face to face meeting. It also allows your new cat to familiarise itself with their new surroundings without being frightened by the other pets in the house.
After you’ve done the methods up to this stage, you can conduct short, supervised meetings between newcomer and resident pets, then you can increase these supervised meetings according to their behaviour.
Avoid any interactions between your pets that result in either fearful or aggressive behaviours. If these interactions are allowed to become a habit, they can be much more difficult to change and prevent in the future so it's better to introduce your pets gradually so that neither animal becomes anxious or aggressive. That’s not to say you can’t ever expect mild forms of these behaviours, but don’t give them the opportunity to intensify. If either animal becomes fearful or aggressive, separate them immediately and start the introduction process over again in a series of very small and gradual steps.
If you’re still struggling to introduce your pets to each other after this, it may do well to seek professional advice with a pet trainer or local vet, someone who has more experience with cats (and other pets should you have any), who can offer you greater tips and advice!