THE most important aspect of introducing a new cat to your resident kitty is to take the entire process slowly! Cats can develop affectionate, playful relationships, but more often than not cats will ‘reject’ one another for a prolonged period of time when first coming into contact with each other. It is essential to prevent fearful encounters from occurring between your cat and the new feline because if any swatting or fighting takes place, they may never move past that initial interaction, and one cat may always be afraid of the other. You do not want to start things off on the wrong paw!
Cats are strongly reactive to olfactory (smell), visual, and auditory stimuli, and the first task that you will have as the proud new mom or dad of two cats instead of one, is ensure that your cats are only able to receive stimulus from ONE category rather than all three.
The new kitty should be placed in their own room when you bring him or her home. Be sure to bring your new cat into your home within a proper cat carrier, so that there is no risk of escape and a fight breaking out with your resident cat.
Open the door to your cat’s carrier once you are safely in the room with the door shut. Allow your new cat to come out of the carrier on their own terms, because introductions to brand new environments are stressful and your new cat should not be forced to explore before they’re ready. Have food and water available close to the carrier, and on the far side of the room, place a litter box ready for your new cat’s use. You can stay in the room with them, or you can leave while they acclimatize to the new surroundings.
By keeping your two cats separated from each other, you can gradually allow them to get used to one another’s scent so that they reach the point where they are no longer threatened by the scent of each other. They will also have a chance to hear one another’s sounds at night when the home is quiet.
After a couple of days have passed, start “scent swapping” with your two kitties. Place a towel or blanket that your new cat has been using close to your resident cat’s bed. If your resident cat hisses and/or growls, then place the item on the other side of the room. Gradually bring the item closer to your resident cat’s belongings (food bowl, cat bed, favorite chair, etc.). Repeat the same procedure with your new kitty, by bringing in an item that has your other cat’s scent on it. If you cannot think of anything that is suitable for this purpose, then simply rub a cloth along your cat’s mouth, face, and back, and it will be well saturated with your cat’s pheromones. Placing a Feliway Diffuser Device (with feline facial pheromone) in the new cat’s room and in another area of the home may help both cats acclimatize to each other’s presence as well.
Continue scent swapping (particularly with the facial pheromones since these are the ‘happy’ cat pheromones!) until both cats are familiar with each other’s smell and there is no hissing, growling, or hiding behavior in response to having the other’s item(s) close to ‘their’ food and/or bed area. The length of this time period is entirely dependent on the two cats’ ages and personalities, and may take anywhere from one hour to several weeks, to slightly longer than a month. Have patience ? it is worth taking it slowly, rather than risking an unsuccessful introduction!
Note: be sure that both cats have been examined by a veterinarian, are relatively healthy, and are immunized before proceeding to this next step.
Once the scent communication has been well established, it is time to start letting the kitties see one another, without actually being able to have physical contact yet. The best possible scenario is to have a screen door between your two cats so that they have an unimpeded view of one another, but other options include using baby gates (modern ones that do not have sizable holes in the mesh/grid/etc. that your cats will fit through) while having the area above the baby gate blocked off, and also opening the door to your new cat’s room wide enough so that both cats can see one another, but not so wide that they can actually squeeze through the opening.
If you do not have a method of screening your cats from one another, then tying the door open at the exact width that does NOT allow either cat to squeeze through to access the other, is a suitable method of allowing your cats to observe one another for prolonged time periods. If your cats are communicating aggressively by hissing, growling, or even trying to swat at one another, you may need to shrink the door opening to just a crack for awhile, so that neither cat gets swatted. You can encourage your cats to spend time at the door with one another by bringing toys over and engaging them in play behavior, and placing treats on both sides of the door. Do not offer any catnip while your cats are still becoming used to one another, because some cats react aggressively with catnip.
Once your cats are making friendly overtures at one another ? sniffing, licking, rolling over on their backs and trying to play with each other under the door and through the opening, and there is absolutely no hissing or growling, you can then conduct your cats’ first supervised visit. Allow your cats lots of space within which to interact with each other, and make sure that there are lots of ‘escape’ options in case one, or both, of them feel the need to make an escape. Place some boxes around the area, or cat beds into which they can retreat, and ensure that there are numerous perches accessible at various heights for both cats where they can feel safe.
If a fight does occur, do not yell at or punish either cat. It will only serve to aggravate the cats and enforce what a negative event they experienced, which is NOT the desired goal. Separate the cats again as before, and restart with scent swapping for several days, and repeat the entire course until it is safe to expose your cats to each other for another trial visitation.
Ensure that there are multiple litter boxes available and that there are also plenty of food and water bowls accessible. Do not feed your cats side by side because this will encourage competition between them.
By taking a gradual approach to introducing your two cats to each other, you are helping to build a healthy foundation to a lifetime of companionship between them! If you run into any obstacles along the way, consult your veterinarian and they will be able to assist you with potential problems. Congratulations on the adoption of your new kitty, and best of luck!