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Introducing New Kitty to resident Kitty


Bringing a new cat into your home is a big deal for your resident cat(s). Why? Because your cats are likely to initially view the new cat as a threat as opposed to a friend. That’s not an ideal way to start a relationship, but that’s the reality with cats. However, there is good news! By following these guidelines, your new cat is likely to be accepted by your current cat(s) and there will at least be peaceful coexistence and, ideally, bonding.

Consider your current cat’s needs.

What’s their experience with other cats?

If your cat has never been around other cats except when they were a kitten, it may take them awhile to adjust to a new cat in the home. Ideally, the new cat is known to enjoy the company of other cats as this will likely make the introduction process easier.

Go slow.

Introducing cats should be a slow process. In fact, the slower the process, the better chance of a successful introduction. "Slow" means at the pace of the cat who is showing the most signs of stress. This may be the new cat and/or the resident cat(s). This introduction may be a matter of days, weeks or months—it's up to the cat. It may be tempting to rush the process, but patience will make everyone in the household (people and cats) much happier in the long run. Here’s how to do a successful introduction:

Step 1: Separate the cats

Your new cat should be kept in a single room during the initial stages of this introduction process. This is important for both the new cat (so they can begin to feel comfortable in their new territory) and for the resident cat (so they can adjust to the new cat’s presence in the home). To set everyone up for success, ideally the new cat is kept in a room that the resident cat doesn’t spend all that much time in. (This may not be possible in a small apartment.) For example, if your resident cat enjoys sleeping in your bedroom, ideally the new cat is kept in a room other than your bedroom.

During this separation period, you can switch the cats’ bedding so that they get used to each other’s scent. It’s also important that all the cats are getting enough daily play time as this will help reduce their stress.

Do not move on to any further steps until both the new and the resident cat are showing calm and relaxed behavior. The new cat should be confidently exploring their room and showing social behavior with the people in the home. The resident cat should be acting as they always did prior to the new cat’s arrival. Only move on when you reach this point.

Step 2: Create positive associations

At this point, you have two or more cats who may be curious about each other, based on their smell, but also fearful and/or stressed by the presence of the other. The goal in this step is to show the cats that good things (like treats) happen when they see each other, to create positive associations.

First, identify a food (other than their regular food) or treat that each cat loves. Moving forward, they are only going to get this treat in the presence of the other cat. Good things can also be play time or even grooming if the cat(s) enjoys being brushed.

The cats should not be directly interacting at this stage. Instead they should be separated by a tall, sturdy baby gate (at least 36” high) in the doorway of the new cat’s room. Neither cat should be picked up and forced to see the other. You can encourage the resident cat to come near the baby gate using treats or play, but again, the pace of this introduction is determined by the cats.

Here are two examples of how to create positive associations using the baby gate (the first would take place before the second):


Cover the baby gate with a sheet so the cats can’t see each other. Remove the sheet for a moment or two until the cats see each other and, in an upbeat tone, say, “Happy cats!” (or anything else you’d rather say) and toss them both a treat. Then immediately cover the baby gate with the sheet. This is easier to do if there is a second person, but can be done with one person. Repeat this activity five to 10 times in a row a few times a day. (It will only take a few minutes each time.) The key to this process is keeping the interactions very brief and positive. Don’t wait for one of the cats to show stress; instead end the interaction on a positive note before any signs of stress.


With a toy in each hand (or better yet, a second person on one side of the baby gate and you on the other), engage the cats in interactive play using a separate toy for each cat. Ideal toys are a fishing rod toy which has a rod with a long string and feathers attached or a cat laser light. Keep the play sessions short. Always stop the play on a good note (before there are any signs of stress) and reward the cats with a treat. If things are going well, gradually increase the amount of time you play with them.

When you see positive indications that show the cats are developing comfort with each other, you can increase the amount of time the cats see each other as well as decrease the distance that you are tossing the treats. These signs include:

  • Eating the treats in the presence of the other cat.

  • Playing with a toy in the presence of the other cat.

  • Ignoring each other and going about their own business on opposite sides of the baby gate.

  • Touching noses through the gate, playing footsies under the gate and/or rubbing their bodies against the gate. 

When you see indications that one or more of the cats is stressed, go slower with the process. If one or more cats shows a particularly high level of stress, than go back a step. It’s not a set-back; it just means that the process is going to take longer than you initially thought. These signs include:

  • Consistent hissing or growling towards the other cat. A hiss here or there is not a concern, so long as the cat is otherwise showing some positive indications as well.

  • Distancing themselves so they don’t see the other. For the new cat, this may mean hiding in their room. For the resident cat, this may mean running to another room.

  • Stressed body language. In particular, look for a swishing tail, ears flattened back against the head or turned sideways, hair on their back is raised, crouching or slinking away.

Step 3: Supervised time together

By this point, the cats are increasingly comfortable with each other, but have not yet directly interacted. Now you can give them supervised time together without the baby gate. Reward them with treats for any positive or neutral interactions. At the slightest indication of a negative interaction (like stalking, chasing or pouncing) distract and redirect the cats with a toy. Aim to end the interaction on a positive note, then gradually extend the amount of time that you allow the cats to be in the same area under close supervision.

When the cats have repeatedly, over at least several days if not weeks, had positive or neutral interactions without showing signs of stress, they are ready for unsupervised time together.

Set the cats up for a positive relationship.

The last part of a successful introduction is making sure that the home environment has enough of everything for every cat, i.e. enough litter boxes, scratching posts, water bowls, food bowls, hiding spaces, comfortable resting spaces, toys and human attention so that the cats do not feel in competition for any of these resources.

It’s also important that there be enough high resting spaces for the cats (any object from a few inches off the floor to a few inches from the ceiling). Cats love to perch and this helps them to feel safe in the home. Also, high resting spaces increase the amount of territory in the home, which makes peaceful coexistence among cats more likely.

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