How to Introduce Cats Without Causing Fear

If you’re considering bringing a new cat into your family with an existing cat, or you’ve already done it and they’re not getting along well, it’s time to think about introductions.

This is also true if you’re introducing a cat to a dog, or if your long-time buddy cats are suddenly unable to be in the same room without fighting.

Introductions are one of the areas where there’s a huge difference between cats and dogs.

Cats are not designed to meet stranger cats and be friends. That’s why careful introductions are necessary, and they can be challenging. In fact, about half the clients I work with are struggling with introductions.

It doesn’t help that there’s a ton of misinformation out there on how to approach this. Don’t worry. I’ll walk you through a slow, positive introduction process and give you lots of tips to help things go smoothly.

Why Properly Introducing Cats Matter

I’ve said it in most of my articles. We did not domesticate cats. We didn’t breed out their natural instincts — including the instinct to protect themselves and their resources. For that reason, your life-long indoor cat is likely to react the same way a wild or stray cat would when a new cat suddenly shows up.

If introductions are not done in a slow, positive way, it’s highly possible that you’ll end up with cats who are more fearful and skittish generally, hide more, want less attention from you, or worse.

That’s where a methodical introduction process comes in.

The Best Approach to Introducing Cats

You’ve probably heard a lot of different introduction tactics from well-meaning friends, your adoption facility, or researching online. While there’s no one way to do it “right,” there are many ways to do it wrong.

Suggestions like forcing the cats into carriers sitting side-by-side or just letting them fight until they “work it out,” are bad ideas.

Anything that forces the cats into scary, stressful situations, with no way out, can backfire. Your cats will be terrified. They’ll put their guard up and leave it up because they’ve learned that being around this new cat means really bad things happen to them.

Instead, try a slow, positive approach.

Don’t Push Too Far Too Fast

The key to successful introductions is to avoid pushing either cat past their comfort zone. Make this your mantra during intro sessions. If the cats show even tiny signs of stress or nervousness, turn the intensity down!

This keeps them from putting their guard up, which stops you from making progress. It’s also less stressful for you because you aren’t putting them in situations that have you on high alert to stop a fight before it happens.

You can turn the intensity down in any step with any or all of these options:

• Limit how much they can see each other
• Put more distance between them
• Shorten the length of the session
• Increase the value of the positive thing they’re focused on. Get out the special treats.

How Long Should Cat Introductions Take?

The truth is, there’s no timeline because we’re letting the cats set the pace by not pushing past their comfort zone. They will let you know when they’re ready to move forward or need you to slow down.

Some cats move through the process very quickly. Others take a while. There’s a lot that influences this — some of which you can control, and some you can’t, like the cats’ past experience with other cats or natural state of nervousness.

But you can help them through the introductions by controlling what you can and respecting their limitations.

It’s safe to plan on months, not weeks, for introductions.

How to Introduce Cats

You'll Need Supplies

• Barrier to place between the cats for introduction sessions. They should be able to see and smell through the barrier. Using a full-door option or stacking two baby gates works well (make sure the gates have vertical bars, not crisscross that your cat can climb).
  
  You can buy zipper screens that tack around the door. Some people install a temporary screen door. Even a piece of garden lattice cut larger than the door can work.
  
  
• Sheet, towel, or blanket to cover the barrier for part of the introduction.
  
  
• Something positive each cat enjoys. Treats (have some high-value treats one on-hand), toys, catnip, brushing, etc. will be used during sessions.
  
  
• Food puzzles can be a great positive thing for the cats to focus on during intro sessions.
  
  
• A harness can be used during the later steps to give you more control, ONLY if your cat is comfortable and relaxed wearing it. Check out our article on harness training.
  
  

Look for Body Language

One of your biggest jobs will be to watch and interpret each cat’s body language. This is how they’ll tell you when things are too intense, and you need to adjust.

If your cat is hissing, growling, swatting, or making other obvious signs of stress, they are pushed way past their comfort zone.

Instead, watch for the subtle signs that happen well before they get to that point, so you can turn the intensity down.

You may see:

• Ears turning, even slightly, to the side or back
• Staring intently/unwilling to look away from the other cat
• Eyes darting
• Tense face
• Cowering (trying to look small) or puffing up
• Licking the lips
• Fidgeting
• Skin twitching
• Tail going from a leisurely swish to a jerky, agitated swish
• Unwilling to focus on, or be easily distracted by, positive things like treats
  
  

Introduction Steps

Following are the basic steps. Keep in mind, you can tweak these based on your situation and how your cats respond.

Every case is unique. The only “one-size-fits-all” element to this process is (everybody say it with me) not pushing past their comfort zone.

Note: If you're doing this solo and don't have another person to help, read the following steps, then make these adjustments.

If you have more than one resident cat, make these adjustments, so it's not so overwhelming.

Keep the cats separate

You’re starting with the cats completely separate, with no visual access at all. Your new cat should be brought into your home and put in a “safe room” to get acclimated slowly.

Step 1: Use their scent

Cats use scent to recognize each other. They also groom each other (called allogrooming) to create a group scent as a way to identify the cats in their social group.

So that’s where we start. You’ll do this step daily through the next couple of steps. Then every other day for a few weeks. Then fade it out as they start sharing space.

There are two parts to this step:

Part 1: Build positive associations with the other cat’s scent

1. Get a small blanket, towel, or piece of fabric for each cat
   
   
2. Place it in a bed or area where each cat rests
   
   
3. Once a day, take that fabric and move it into the other cat’s area. So, the new cat’s fabric goes in a room with the resident cat and vice versa.
   
   Don’t put it in the other cat’s bed. We don’t want to invade their safe spaces. Just set it in the room with TREATS on top. That’s what starts to build the positive association, “every time I smell this scent, I get really good stuff! I like this scent!”

Part 2: Build a group scent

1. Use a soft bristle brush or clean cotton sock (no scented detergent)
2. Brush or rub one cat’s cheeks and shoulders
3. Then take the brush/sock to the other cat. Let them sniff it.
4. If they’re relaxed, give them a treat (positive associations) and brush/rub them with the same brush/sock.
5. Then go back to the first cat, let them give it a sniff, treat, and rub if they’re OK. Now they smell like each other.
6. Note: If either cat shows any signs of stress when sniffing the brush/sock, don’t force it. Drop it nearby with a treat for a few days and then try again. If they still aren’t open to it, just skip this part.
   
   

Step 2: Rotating or swapping spaces

When your new cat is feeling secure in their safe space (i.e, moving around comfortably, eating, drinking, and using the litter box normally, relaxed enough to play and interact with you), it’s time to let them start exploring the rest of the home.

You’ll continue this through all the remaining steps until the cats are living together full-time.

1. If you have an extra room, you’ll set aside time each day to put your resident cat in the extra room (ideally with something fun to do) and give your new cat the opportunity come out of their “safe room.”
   
   
2. If you only have the “safe room” available, you’ll have to swap the cats. Your new cat comes out of their “safe room” and the resident cat goes in the new cat's “safe room,” with no contact (or as little as possible).
   
   This isn’t ideal, in my opinion. Your new cat doesn’t have the option to retreat to their “safe room” if they get nervous. And your resident cat is forced to stay in a room that smells like the new cat. But, if you only have one room to use, we make it work.
   
   Start with very short sessions, if needed. And be very mindful of each cat’s comfort level. If either seems nervous, get them swapped back quickly.

Step 3: Barrier work

When the cats are doing well with the scent step, and your new cat is starting to feel comfortable coming out of their “safe room,” you can start dedicated introduction sessions with the barrier (baby gate or zipper screen set-up).

You can do this once a day or more, if time allows and the cats are comfortable.

Between sessions, the door is closed, and the cats go back to not seeing each other or interacting at all.

These are short sessions, to start. The cats will be focused on something positive, like treats, catnip, very mellow play, petting, brushing, etc. When you can no longer keep them interested in their positive thing, the session is over.

There are three parts to this step:

Part 1: Covered barrier

You’ll set up the barrier between the cats. It’s usually easiest to do this in the doorway of the new cat’s “safe room” if space allows.

1. Cover your barrier with a blanket or towel so the cats can’t see each other
   
   
2. Using their positive things (we’ll use treats for the purposes of this article, but anything they love is fine), you’ll start them as far apart as they need to be to relax and focus on those treats. They may glance at the barrier. But they should go back to their treats easily. If not, back ‘em up.
   
   
3. Every couple of sessions, as long as the cats have stayed nice and relaxed, you’ll move them a little closer to the barrier for their treats.
   
   
4. Continue this until they’re about 5 ft. apart
   
   

Part 2: Uncovering the barrier

With the cats 5 ft. apart and focused on their treats, you’ll gradually start uncovering the barrier so they can see each other.

1. Uncover just a couple of inches for the first few sessions
   
   
2. If that goes well, continue uncovering, a few inches at a time over subsequent sessions, until the barrier is completely uncovered.

Part 3: Hangout sessions

This is where the cats can start to acknowledge each other a bit more, but still with the protection of the barrier and your positive distractions. You can go with the flow here.

1. Start making the sessions longer and pull back a bit on the treats or other positive focus.
   
   The cats start to notice each other more, move around a little, maybe approach the barrier if they’re both OK with it, etc. But you’re still right there with positive distractors so you can keep everyone relaxed and happy and pull their attention away from each other if things get tense. It should still be positive and calm the whole time.
   
   
2. How long you stay in this step is really up to you. Some people like to work up to 5–10 minutes and then move on. Other people prefer to work up to longer sessions of 30+ minutes, where the cats eventually lose interest and wander off (indicating that they’re not concerned about each other).
   
   Just remember, you still need to be there for constant supervision and occasional positive distractors and reinforcers.

Step 4: Removing the barrier

When they’re doing well with the hangout sessions, you’re ready to move on.

Now you go back to shorter sessions with the cats focused on their positive thing the entire time. (If you’d like to continue doing some of the longer hangout sessions too, that’s fine — maybe one of each per day.)

1. With the cats 5 ft. apart and focused on their treats, you’ll slowly start opening the barrier the same way you slowly uncovered it. Just do a few inches at a time, working up to fully open.
   
   
2. The cats should be focused on the treats. This is what keeps them from rushing toward each other or through the barrier. When they’re done with the treats and you can’t easily distract them, the session is over. And they go back to being separated with no visual access.
   
   
3. This is where having them in harnesses can be helpful.

Step 5: Supervised time together

You’ve made it to the last step! This is where the cats gradually start sharing space.

1. When you’ve made it to this point, your cats shouldn’t be showing signs of fear or aggression. They may be a bit nervous here and there, but relax quickly with your positive distractions.
   
   Sometimes one cat is actually really excited to get to the other cat to play or say hello (especially young cats). A harness can give you more control over that cat, so they can’t rush toward the other and startle them.
   
   
2. You’ll start with short sessions, cats on opposite sides of the room, focused on their treats.
   
   
3. Over multiple sessions, gradually move the cats closer together while focused on their treats and increase the length of the sessions.
   
   
4. As they get closer and sessions get longer, start pulling back on the treats so they notice each other and interact a bit more. Maybe you go from separate piles of treats to giving one treat at a time with the cats a little closer to each other.
   
   Then, when ready, on to separate mellow play sessions. Then to a shared play session. Tweak the timing and activity, as needed, to fit both cat’s preferences and comfort levels.
   
   
5. When they’re doing well here, you’ll start gradually giving them more freedom/less supervision, until you feel they can share longer periods of time together, and then live together full-time.

Introductions with One Person

While it’s easier to have one person per cat, that’s not always possible. If you’re doing introductions solo, just make a few adjustments:

• Cover only the bottom half of the barrier, so you can see both cats over the top.
  
  
• You’ll stay on the side with the cat who needs the most support. Your more relaxed cat can be on the other side. Same in the final step when they’re on opposite sides of the room.
  
  
• For the cat you’re not with, you’ll need a positive thing that can hold their attention on its own. Food puzzles or scattering treats work for food-motivated cats. Catnip can be a good option. You can even toss treats, one or two at a time, or play through the barrier.
  
  
• Harnesses will give you more control in the later steps.

Introductions with Multiple Cats

If you’re introducing your new cat to multiple resident cats, the process is pretty much the same. You’d have all your resident cats on one side and your new cat on the other. If that’s overwhelming for you to manage or your new cat to tolerate, that’s OK. Break them up into groups.

You can do one-on-one, one-on-two, whatever works best.

For example, introducing two resident cats to one new cat may mean two or three intro sessions per day, one with the new cat and resident cat A, one with the new cat and resident cat B, and then maybe a shorter session with all the cats if that’s feasible. Do what works for you and your furballs.

Cat Introduction Tips

• Stay calm. If you’re nervous, your cats will be nervous.
  
  
• Using food puzzles or scattering/hiding treats is a great way to slow your cats down during the intro sessions. They’ll need to focus more on getting the treats, meaning less focusing on each other.
  
  
• It’s helpful to do play sessions with each cat before intro sessions. Burn off some energy so they’re nice and relaxed.
  
  
• If you have a hard time keeping one cat from rushing toward the barrier, position that cat at the barrier and control the distance with the other cat on the opposite side.

If things aren’t going as planned or you feel like you’re stuck, there’s still hope. Reach out to a certified feline training and behavior consultant. This is a huge part of our work. Sometimes there’s a particular trigger that’s causing stress. You could be missing a super subtle sign of nervousness.

We can even look at secondary things that contribute to challenging introductions, like general stress reduction, managing play aggression, making sure resources are set up in a way that promotes comfort for the cats, limiting resource competition, and more. There’s so much we can try before you get to the point of surrendering a cat or trying to live miserably with them separated in your home.

Just remember, your cat is acting on thousands of years of instinct. You can’t change that instinctual reaction. What you can change is the situation, so your cat doesn’t have to react in that way.

Just be patient and listen to their cues. You’ll get through the introductions stronger than ever.

You can also check out this podcast where Marci Koski talks about adding another cat to your home.