How to Introduce Cats to Each Other

When you introduce cats to each to each other, it really is like opening a box of chocolates: you never know what you’re gonna get.

After a lot of hissing, posturing, chasing, and playing, it took Shorty and Kodi a miraculous 1 week to get along. I get asked that question a lot, right up there with Why Did You Name Her Shorty, and Is Your Hallway Haunted? They still had their moments of establishing boundaries and territories, but it wasn’t a rare sight to see them snuggling atop the cat tree.

Obviously bringing a new cat into a home already under cat-rule is a common anxiety we all share in the adoption process. But that very anxiety could be our undoing since cats — well, animals in general, but cats in particular — are sensitive to our moods and have demonstrated remarkable abilities science hasn’t even explained yet. Thus, since some cats may be able to smell cancer and even sense when we’re going to die, it isn’t a stretch to think they know when we’re feeling very anxious.

These tips won’t work for every situation, but remaining calm and patient is an important first step. Monitoring their initial meetings is also necessary as thrusting them together with a just-let-em-work-it-out mentality could be such a stressful and even traumatic experience for them that they may never get along and even develop behavioural issues (aggression, not using the litter box, social withdrawal). Remember that in the wild, cats have lots of space, escape routes, hiding places, secret vantage points both high and low, and lots of time to assert their presence, establish their territory, and develop relationships. We don’t have to mimic the wilderness exactly, but considering and respecting the conditions from whence they came will go a long way to creating a peaceful and fulfilling life for your cats.

Here are the 12 steps listed in our video, How to Introduce 2 Cats to Each Other.

1. Let them say hello through a closed door. Allowing both cats to smell each other while remaining in a safe place unthreatened removes a great deal of fear. Domesticated cats are getting better at learning from rewards, but they may still retain the fear-based learning system of their wild brethren, so it is vital to avoid traumatic, fearful events that could potentially scar this and future relationships for life.

2. Open the door. If you feel they are beginning to adjust to each other’s presence, i.e., if the hissing and growling have reduced to an occasional grumble, slowly open the door. This may happen after a few minutes, a few hours or a few days. (Some people find it useful to allow them to play with each other’s toys or blankets to get used to the other’s scent.) Speak to them in a calming, praising voice, and be sure that you are actually feeling calm as well. Cut the meeting short if you sense the aggression may escalate beyond a little hissing and posturing; you want them to part ways without fighting so they learn the other is not a threat. You can conduct another brief meeting once they have calmed down.

3. Show your cat the new kitten is a friend. Your current cat may not know if this seeming intruder is friend or foe, so demonstrate petting and praising voices to the new family member. You’ll see in the video it doesn’t go a long way to easing Shorty’s anxiety, but at leasts it sends the initial message.

4. Let the new cat explore, but be prepared! Stay calm but follow the new cat around and be ready to intervene if something goes awry.

5. Make sure the little one has a place to hide if he gets scared. Places to hide and multiple paths and escape routes are necessary for the constantly calculating cat to feel safe and in control.

6. Be patient while the new cat adjusts to their new environment. They may will get into trouble but exacting punishment on every move they make builds nervousness and tension, so save the big NO!s and spray bottles for the big problems.

7. Distract them with toys so they show each other they like to play. This lets them see that they’re on a common ground with common interests and perhaps not such a threat after all.

8. Supervise playtime while they get to know each other. Once you feel any aggression has subsided, let them play, wrestle, hiss and explore each other, but keep a watchful eye with vocal reminders to be “gentle” to let them know you’re still around.

9. Let the little one get the upper hand. This obviously depends on your cats, but the new occupant needs a little confidence in their new realm. Let them explore the bounds of their new relationship, reserving guidelines for the big blowouts.

10. But let him be reminded who’s the boss. You have a cat who has been the master of the house and now you’re introducing another member of their species in their home who threatens to claim territory. Be sensitive to the anxiety your current resident cat could be feeling and still pay lots of attention to them to ensure they feel safe. You can’t let one always be the dominant player, so encourage and discourage each of them equally while they assess their place in this new society.

11. Give lots of praise and love to each of them, especially as they get closer. This is important – any type of closeness without fighting is to be highly praised with your best kitting-cooing baby voice and treats. They need to know that’s the best thing they could do.

12. Relax, cross your fingers and hope for the best. Every situation is different, so you really have to allow your cats to determine how long you stay with each step. I know some people who haven’t been able to let their cats be in the same room for weeks at first, but end up being best friends. Be patient, be calm. Results will vary, to be sure, so leave your comments and questions below to help others or if you’re seeking guidance with your cats.

11 thoughts on “How to Introduce Cats to Each Other

  1. Hi…just love your blog and following you on facebook.
    Always amusing to see what’s up on a daily basis!
    My husband and I have 2 cats. Our older cat is 8 yrs and we adopted a kitten at 10 wks from the shelter after our 15 yr old cat died. We introduced the two as you advised. But 3 months later, they still don’t get on well. From the start our kitten Lola has been very aggressive in her play with Molly, the 8 yr old. Molly is easy to get along with, and Lola is the queen of love and snuggles. But Molly rarely wants Lola near her because of all the play biting that went on for 2 months. Lola has always been friendly and loving toward Molly but when she wants to play she plays rough. I try to let them work it out but sometimes I have to intercede for Molly’s sake. Lola wants to snuggle all the time with Molly but she rarely tolerates it. I have tried giving treats and praises when they are together. But I wonder if they will ever be completely loving toward one another. Early on Molly would play tag with Lola and bring her toys, but she has stopped that because of Lola’s aggressive play. Both cats are very , very loving. What is your take on all this?
    Thanks so much,

  2. Love Shorty and Kodi.
    Rose (buff color with gold eyes)
    Pearl (totally black with green eyes)
    And their human

  3. Despite following all the suggested step for introducing the new cat, after more than 6 months my cats were still fighting, with the older one hissing and chasing the little one. They can roam outside so the older one used to stay outside all day long, hissing at us and scratching us if we tried to pet him. No play. A real disaster. Then 1 month ago we were suggested to give him Bach flowers and in 2 days we got our cat back, still fighting with the little one but more as a sort of play and normal with us (more at home and friendly). I’m writing this for the ones that are not as lucky as you with Short and Kodi. It’s hard but there’s a way!

  4. Hello, and thank you for your awesome website (and your cute cats) <3
    You talk about a new cat arriving in your house, so you already know the house, and the "elder" cat also knows it.
    What about when you are both new? When you arrive with your cat in a new house already owned by a cat? In this case, I can't be like petting the king cat in order to tell him my cat is cool. I don't know the king cat very well, and this seems to be necessary in your article.

    Also, when they fight, with real screams and claws (we followed the steps. They smelled each other nose, very friendly. New cat decided to go in the full house and claim the sofa was hers. King cat arrived, they fought like they never met before), what can we do? We threw a blanket on one of them in order to take him away. Maybe we should let them fight? But can they hurt each other?


      1. Thanks for your advices. Just to say they now accept each other (it took 3 months). They are not the best friends at all, but they often play, chasing each other… turn this into something wich is not really a game but each one then goes to its place in order to avoid the real fight.
        However, the “owner cat” still pretends the new cat’s place is his, and it seems there is no way to let the new cat have a proper personal place.

  5. Hi Rob, thank you so much for such awesome information! I’ve had a really difficult introduction so far going on 4 months. I wish I would have read and seen your stuff before hand. I’ve been emotional about it and now I know this has caused trouble. My guy is deaf also, he’s 7 and new guy is 2. They have been separated but at first went thru a fast introduction and they had some tense run ins. My guy was being very dominant with the death stare and stalking, and jumping on the back and biting the back of neck stuff. So they’re back to complete separation now, and even two doors and a hall are separating them because my guy reacts very unsettled even smelling new guys scent. If he catches the scent he runs madly around the house stalking and yowling. I admit I’m still worried and afraid to move forward and I know this is probably making it worse. But I also wonder if his being deaf might be making this more stressful for him? Any guidance would be so greatly appreciated, we are in love with both cats and have to make this work!! Thanks so much, Kelly

    1. Hi Kelly. I had been thinking of your question for some time and I asked Mikel Delgado, Certified Cat Behavior Consultant at Feline Minds, for her input. Here are her thoughts: “Many cats are sensitive to the presence of a new cat, so we don’t know if being deaf is necessarily making things worse – but it is easier for deaf cats to be startled, so many of them need more time for an introduction. Often a much slower introduction is going to be necessary – especially if they’ve had some fights. The way to go forward is to start over, one sense at a time (starting with scent, then likely introducing the cats with a physical barrier such as stacked baby gates) and pairing interactions with something both cats like, such as food. I would definitely recommend you work with a qualified cat behavior professional (such as a veterinary behaviorist, Certified Applied Animal Behaviorist, or Certified Cat Behavior Consultant) to help you with this introduction.” I hope that helps!

  6. Hi. I really need some advice. When my elderly cat became ill and was soon to pass, I thought I was doing the right thing for my younger cat by getting her a playmate, a male rescue kitten. She hated him, and would try to attack him every opportunity she got. It’s been over two years now, and while they barely tolerate each other I know they won’t do each other any real harm. My problem is, that because the newer cat turned out to have some fairly major health issues and some deformities, he is an indoor only cat. He was tried on a harness so I could take him for walks outside, but became extremely aggressive towards me when I tried to get the harness on him so we stopped trying and he stays indoors all the time. Because of this he was becoming a bit lonely so we adopted a 10 month old rescue boy as company. This has worked out well for the boys, who get on fine, BUT, my eldest, who is a female quite literally wants to kill the youngest. While I anticipated some aggression on her part towards the new boy, I never dreamed that 12 months later they still have to be separated ALL the time. Her aggression knows no bounds, and if she goes outside and I let the boys out into the room she can use during the day, she’ll come back in when they’re back in the main part of the house, and spray everywhere. She will attack the youngest through a tiny gap I’ve left open in an interior window, (the purpose was for them to get to know each other), or under the door, and she is NOT playing, she is in full on attack mode. I was sitting on my lounge with her one day with the newest one over the other side of the room, just getting her used to him being there, and she full on attacked me, resulting in blood everywhere and me in hospital on an intravenous drip. I’ve spent hundreds of dollars on Feliway, which I felt did next to nothing, but have yet to try Bach Flower Remedies. The real problem will come in three days, when I have to move into a much smaller home. Please is there something you can recommend I do when introducing all three cats into this new place that might get my eldest to be more accepting of the youngest. I hope you can understand all this. Thank you so much. Linda.

  7. Hi,

    Thank you so much for sharing this information with us! I’ve adopted a female cat and she’s been with me for 3 months. She is 5 months old. As much as she loves me, she’s a free spirit and loves discovering. I live in a one bedroom apartment and I work 5 or 6 times a week. I figured my baby girl needed some company so I adopted another kitty (7 months old) yesterday. The new cat is such a love, she’s not as independent as my resident cat. I tried to put the new cat in a safe room which is my bedroom and she knows she’ll be slightly safer under my bed. However there’s almost no way for me to close the door and chill in the living room with my resident cat because then new cat is needy and scared. While my resident cat keeps being territorial and hissing. She chased her around (managed to open the door), you can feel the stressful vibe but never really attacked the new cat. The new cat could care less, but she’s trying to figure out why this is happening!

    Long story short, there’s almost no way for me keep the door closed as they keep wanting to go in and out!

    PS: new cat hasn’t eaten yet (although she drank just a little bit of water) and resident cat ate a couple time but I can tell she doesn’t have the best appetite.

    Please help!!

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