How to Introduce New Cats to Each Other

Opening your loving home to another kitty is always a noble gesture, but your current cat might not agree quite as wholeheartedly. As cats tend to have more diverse personalities than even humans, it’s often impossible to tell how your “firstborn” will receive the next member of the household, especially if you’ve never had another cat in the home before. This means the advice for introducing new cats to each other varies widely and there’s no foolproof process that works for every pair. Guidance from experts can be daunting, confusing, and even conflicting, so Mau scoured the research to bring you the most universally accepted tips for bringing home a new kitty when there’s already a fur-boss living there.   

Do all cats need a strict introduction process?

No. But you can’t know if your cats do until it’s potentially too late and starting on the wrong paw can set you back for months, or possibly forever, so it’s never advised to take a pass on this no matter how friendly your current cat is. Some pairs breeze through this process quickly and others take considerably longer, but every set of new siblings needs to give it a go.

Okay, so what’s first?

All experts agree that separation is essential from the start. This means that, before you even bring a new cat home, you need to prepare a room where he can live without seeing, or being seen by, your current furbaby. This space needs to have its own litter box, feeding bowls, toys, and cat furniture that he can rub his scent all over. Because cats are so fiercely territorial, the new kitty needs to be able to assert his scent, and only his scent, throughout his environment to establish security and comfort. Likewise, the current kitty will benefit from not having his space (the rest of the house) affected by a new scent.

And then?

The most commonly recommended method of slowly introducing new cats is through feeding time. Bowls should be placed on opposite sides of the door dividing your cats’ personal spaces, gradually moving them closer to the door with each successful feeding (successful = minimal growling or other aggressive/defensive behaviors). When the bowls are touching the door and both kitties are happily munching throughout the meal, your cats are at least comfortable with each other’s existence and scent. It’s now time to start mingling their scents.

By letting them in each other’s spaces?

Yes and no. It’s certainly not time to throw open the door and watch what happens, but it’s time to scoop up a new kitty, exit the room, let the current kitty in, and close the door again. Now you can let the new kitty loose in the rest of the space. It’s a temporary housing swap. The goal here is for the cats to explore each other’s environments and leave their scents on each other’s belongings, so encourage them to play with each other’s toys, snuggle down in each other’s cat caves, and climb each other’s cat trees. The goal here is for them to touch as much as possible before switching back. Warning: It’s important that the cats not see each other when making the switches. This is a scent-only operation.

That was fun. Now what?

Once they’re happily back in their original environments, they’ll likely occupy themselves with investigating the new scents left behind on their belongings. Hooray! This was the point of the swap. From here, there is some diversion in thought from behaviorists. If your furballs are still acting a bit antsy or anxious, you should proceed with a visual introduction through a barrier, which means double-stacking baby gates where the door currently stands closed (or investing in a tall pet door that’s high enough to thwart the most impressive of leaps). On the other hand, if they’re both fairly desperate to get back to each other’s spaces and neither are showing any signs of aggression toward each other through the door, you may be able to move directly to combined play.

Yay! That sounds fun!

It can be and, if they’re truly ready, it will be. This is the trickiest part of the process to pull off, and it will help if you have a second person in the house, but only if this person is someone the current kitty is familiar with and already likes. Here’s what you’ll need: treats, toys, a blanket, and another kitty-approved person, if possible. Here’s what you’ll do:

*Find the room with the least amount of available hiding places and seal them off (look for beds with underneath access, low tables, secret nooks, and exits).

*Bring current kitty into this room and begin playing with her favorite toy, getting her as engaged and active as possible.

*Introduce new kitty to this room, as far away as possible, and begin playing with the new kitty with a different toy (this is where an extra person is helpful—if both cats can be engaged simultaneously, you’re seriously increasing the odds of success here). Give treats to each and talk to them calmly and kindly. Your nerves will be apparent to both cats, so try to leave them behind. It doesn’t matter how well this goes the first few times, so don’t worry about it.

The goal here is not necessarily to get them playing with each other but to have them meaningfully engaged at the same time in the same place so they become comfortable with coexisting and sharing their now-combined territory. Don’t wait until a feud erupts to end the experiment. The minute you see prolonged ear-dropping or hear continued growling, it’s time to calmly scoop up the new kitty and take her back to her private space. Don’t scold or punish either cat for the behavior or you’ll reinforce that the other cat brings trouble. Just separate them pleasantly, and spend some time playing with each in their own space. You can try the combined play experiment again in an hour or so if the aversion was mild, or the next day if it was on the more severe side.

Why did I need a blanket for this?

If one of your cats is supremely unready to share a space and goes on the attack, your only recourse may be to toss a blanket over her to prevent violence and easily remove her. Even in this case, try not to scold or punish; the goal is just swift removal and mood readjustment. You’d rarely need to do this, but you need to be prepared for it, just in case.

Are we there yet? 

If your cats repeatedly succeed at playing in the same room without violence or serious threats, try feeding them in the same room at the next meal, but place their bowls at opposite sides of the room. If this, too, goes well, you’re probably ready. Leave the barrier door between their spaces open now. It’s okay if there’s still some hesitation between the new buddies, and even a little growling or defensive posturing. As long as there aren’t physical altercations, some continued trepidation is fine. Keep in mind that not all pairs will become best friends or even friends at all. This is almost completely up to the two cats’ personalities, and some pairs will only come to cohabitate, never cuddling or playing together. Of course, this isn’t the dream, but it’s not a problem either.

How long this takes is completely up to your cats and their inclinations for socialization. The basic marker for determining when you’re ready to move on to the next step is simply your cats’ behavior. If there’s growling, hissing, or any type of aggressive behavior, they’re not ready to move on. If they’re hanging out by their shared door, playing pawsies beneath the door, or singing persistently to have the door opened, they’re at least ready for the next step, wherever you are in the process. Don’t jump to opening the door directly; always go only to the next step. For especially social cats, this entire process may last less than a day. Other cats may take months. Remain patient and calm; some months of slow-going will prevent years of unhappiness and the possible need to rehome. If your cats are having a difficult time adjusting, you may need more individualized plans and more detailed guidance from pros like Jackson Galaxy, but these simple steps will help the majority of cats successfully meet and greet each other in your gracious home.