Nice To Meet You: The Basics of Cat To Cat Introductions

Author: Chris O’Neil, Founder, Catology – Cat Behaviour Solutions

Bringing another cat home can be a stressful experience, not just for the new cat, but also for the current, resident cat(s).  Given that cats are such territorial creatures, most newcomers will be met with trepidation, and a “threat until proven otherwise” viewpoint from the resident cat.

A proper introduction process is essential to ensure the best chance of a harmonious household.  Now, there are those lucky guardians who just seem to let the cats be together from day one and they become best friends!  This does happen in some cases, but I cannot in good conscious recommend this approach.  One fight in the early stages of getting to know each other is all it can take to ruin the chances of a potentially good relationship.

A proper introduction can give the relationship the best chance of blossoming, and the two (or more) cats becoming friends (or at least, acquaintances)!

So, how do we introduce two cats?  The process is quite simple.  There are three phases to the basic introduction, with some supplementary activities to do throughout the process. 


The 3 phases of an introduction:

  1. Complete separation (can’t see each other, but will be able to smell each other)
  2. Visual access through a barrier
  3. Complete access


Supplementary activities:

  • Scent swapping
  • Space swapping


Let’s go through these in a bit more detail.


1. Complete separation

Before you bring your new cat home, a “Sanctuary Room” will need to be set up that the newcomer will live in for a few days/weeks.  The room will need to have the basics, as well as be enriching (e.g. food, water, litter, scratching post, cat tree/tower, soft music, feliway spray etc).  This room should be a haven for the new cat, and give them time to get used to their new surroundings (sounds, smells etc). 

Once you bring the new cat home and put her in her new sanctuary room, the resident cat will undoubtedly smell her and be aware of her presence.  This may cause some negative behaviours such as hissing or posturing around the sanctuary room door.  This is ok and is normal.  After a few days, or even a week, the resident cat should be desensitised enough that he’s no longer behaving negatively.  If he is, you may need to wait a few more days, or work on a counter conditioning procedure with a behaviourist.


2. Visual access through a barrier

Once both cats are relaxed and no longer showing any negative behaviours, it’s time to begin the second phase (though remember that there are supplementary steps – scent swapping and space swapping which can happen before now – explained a bit further down). 

For this step, you’ll need to find a barrier of some sort that you can use to block the doorway but can be seen through.  If you’re handy, a cheap screen door is best, but otherwise a piece of lattice panel from the gardening section in Bunnings can work quite well too.  This step will also be easiest if you have another person to help.

The idea here is to start exposing the cats to each other visually, while pairing the experience with good things (tasty treats).

There are two aspects to this step to be aware of – distance and duration. 

Essentially, one person should be in the room with the new cat, and another outside the room with the resident cat, with some treats handy. 

Distance the cats as far as you can.  The new cat in the room behind the barrier, and the resident cat three to four metres away outside the room if possible.  The person who is with the new cat should open the door so that both cats can see each other, immediately treat both of them, and close the door again.  The whole process should take about 5 seconds.  Do this again maybe five to six times, and that’s it for that day. 

This process is aiming to “pair” the sight of the other cat with tasty treats, so that every time they see the other cat, good things are happening!

The next day, keep the same distance, and open the door for a bit longer, maybe 10 seconds.  Each day, increase the time until you get about 20 seconds with the door open and each cat is staying with you both, getting treats.

Then you can move a bit closer by about a metre.  Reset the time to 5 seconds and keep building on that again.  Eventually, you should be able to have the two cats about a metre apart either side of the barrier without any negative behaviours. 

If you do end up moving too fast and some negativity happens, you must finish the session for that day, and pick up again tomorrow at the previous distance/time.

Once the cats are completely ok with visual access, you can just leave the door open permanently with the blocker up whenever you are home.  This will further help the desensitisation process


3. Complete access

This final phase will mirror the previous phase, just without a barrier in between.  This should go a lot quicker since you’ve already built a solid “relationship base” with the previous phases (and supplementary steps discussed shortly). 

Start at a longer distance with a short duration.  Gradually decrease the distance and increase the duration until both cats are happy to be near each other, receiving treats.  Once this is done, you can start to let them have free access to each other for small periods of time (30 seconds or less) in the same room. 

If it looks like a fight is going to break out, distract or block the cats to stop an incident from progressing.  Gradually build on the duration until both cats are happy to be in the company of the other.  You may want to separate them when you’re not home, at least in the beginning, until you’re confident they can spend large amounts of time with each other unsupervised.


Supplementary activities: scent swapping and space swapping

These activities are just as important as the other phases of the process, and will help it go a lot quicker.  They can start after the first few days of the new cat coming home (give her a few days to calm down and get used to her surrounding first) and continue throughout the entire introduction process.


Scent Swapping

What we are trying to do here is get each cat used to (or even excited about) the scent of the other.

Use a clean cloth or sock to rub one cat around their face and neck.  This needs to be a positive process so don’t force it if either cat doesn’t want any “affection”.

Then go and place the cloth in the other cat’s territory – put it on the floor in a non-threatening spot, away from any important resources (food, water, cat trees etc).

Ideally the other cat will come and sniff the material.  If there is negative body language (hissing, posturing etc), it’s a sign we’ll need to take the introduction slow.  If there is indifference or positive interest, this is good.  We can further make this a good experience by putting some treats around the cloth.

Repeat with the other cat (use a fresh cloth), and do this daily.


Space Swapping

Basically, this activity simply means swapping the cats and putting them in each other’s space for some time.  This further allows each to get used to the smell and presence of the other.  They will likely want to use the litterbox and rub up against things in the other’s territory to combine scents – this is a good thing and should be encouraged.

You may need to wait a bit longer to start this, depending on how eager/confident the new cat is to come out of the room.   If she is an anxious cat, she should never be forced out.  Instead, for the first few days it’s better to put the resident cat in another room, and open the door for the new cat to explore on her own first.  Once the new cat is comfortable in the new territory, it will be easier to sneak the resident cat into the sanctuary room and close the door. 

Space swapping can go for as long as you like, ideally daily.  It needs to be a positive experience so if either cat shows anxiety or other negative behavior, it’s time to stop and put them back. 

There you go, the formula for a successful cat introduction.  It may sound like a lot, but it is worth it in the end.  Some introductions don’t always go to plan and need some tailoring, so if you’re still struggling after following this process to the letter, it may be time to check in with a behaviourist.