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How to Introduce a Second Cat or Kitten (With as Little Drama as Possible)

October 2nd, 2018 by Cherished Companions Animal Clinic

Jasmine is not excited to learn that her family is getting a second cat.

So, you’re getting ready to bring a second cat or kitten into your home…

Everyone is delighted about the new addition to your family… except your cat that already lives there.

Hiss, hiss, me-ooooow!

We know that feline World War III is not your idea of a good time. That’s why we’ve asked Dr. Ivy, one of our cat veterinarians, for guidance.

Here are her tips to help you bring a second cat or kitten into your home, so you can introduce your cats with as little drama as possible.

#1: Cats can be VERY territorial, so go slowly with the new introduction

Yes, you want your cats to get along quickly — or at least tolerate each other.

But rushing things can be a recipe for a rocky future!

If you go too quickly, your existing cat may get territorial or have such a negative impression of your new cat that it can never be broken. So, start slowly.

#2: Start out by confining your second cat or kitten to a small, comfortable space

For how long?

Typically, a few days to a week. (This assumes your existing cat is healthy and up-to-date on shots.)

If you’re getting a new kitten that’s sick, you may need to keep the cats separated for a bit longer.

(Chat with our vets to figure out what makes sense for your cats.)

spare bathroom is the perfect spot to make your second cat or kitten comfortable.

Maggie, the new kitten, gets comfortable while she waits to get introduced to her new feline sibling.

Ideally, you want a room that doesn’t have a lot of in-and-out traffic.

Set up a bed for your new kitty, include food and water, and get that litter box in there, so your cat is totally comfortable.

#3: Allow your cats to smell each other under the door

Once your second cat or kitten is comfortably set up in a confined space, it’s time for the first meet-and-greet…

Allow your cats to smell each other with the safety of a door between them.

Muffin sits by the door to the bathroom -- she knows the new cat is in there.

This is a safe way for your cats to get used to each other’s scents without feeling too threatened.

You can put your existing’s cat food bowl near the door to encourage interaction.

After a few days, you also can try putting a toy at the bottom of the door to see if they want to play.

You’re hearing some hissing?

Don’t worry, it’s normal.

#4: Swap your cats’ “happy” scents

Cats have scent glands in their cheeks.

(Ever notice your cat rubbing his or her cheeks against your legs and furniture? Your cat is leaving pheromones.)

You may want to rub a toy or a blanket along your new cat’s cheeks and give it to your existing cat.

Then, do the same with your existing cat to your new cat.

This can help your cats get used to each other’s scents.

Speaking of pheromones, we have clients who swear by diffusers that release stress-reducing cat pheromones (brands like Feliway).

You can buy them over the counter at local pet supply stores in Castle Rock.

(Full disclosure, we also have clients who say they don’t work.)

If you want things to go smoothly, though, it doesn’t hurt to give them a try.

Set the diffusers up near the room where you’ve confined your new cat or kitten, and let the stress reduction begin!

#5: Introduce your new cat or kitten to different parts of your home slowly, while your existing cat is contained

Once your second cat or kitten is familiar with the confinement area, give that cat some time to visit other parts of your home too (without interacting with your existing cat).

Temporarily confine your existing cat to a different room.

The thing to avoid is just opening the door and letting your cats go at it.

Socks, the second cat, explores and takes in the view, while the other cat is temporarily confined in a room.

#6: Start leading supervised interactions (Big step! Are you ready?)

First, the good news:

Your cats are more likely to fight if you skip or rush the steps above.

Now, the reality check:

Skirmishes still can happen.

It really depends on each cat’s personality and history.

At the very least, expect some hissing and standoffish behavior.

It’s normal for cats to express their displeasure with each other in their initial encounters.

Moby is not impressed with the new cat.

To minimize the risk of swatting, lunging and fighting, consider putting your cats on harnesses with leashes.

That way, you can quickly separate them if things get too heated.

You also may want to have a squirt bottle handy.

Supervise at least two interactions before you decide whether it’s time to let the cats out together in your home.

Take heart, it will take some time for your cats to tolerate each other.

How to know whether your cats will be able to get along

Be patient.

Give it a good two weeks and expect some issues. It can take a little while to know whether this transition will work.

A new kitten tiptoes past an adult cat. They seem to be getting along.

If you see any of the following behaviors in either cat, you may want to slow down the introduction:

  • Hiding more than normal
  • Being very standoffish
  • Marking territory
  • Fighting

Make the transition more gradual, and be sure to supervise interactions.

After a few weeks, you’ll have a better sense of whether your cats are going to be able to get along.

Some cats may never like each other, but they’ll form a truce and avoid each other.

If your cats are still viciously fighting or marking territory at three to four weeks, you may need to revisit your options.

(Both cats may be wonderful… but you may not have a winning combination.)

If things are really bad right away, you may have to consider your options sooner.

Will cats of certain genders get along better than others?

There isn’t hard proof that gender can make a difference in whether your two cats will get along or not.

With that said, there is some anecdotal evidence that suggests you may have fewer issues if one cat is male and the other cat is female (rather than two females or two unneutered males).

BEFORE you bring a new cat or kitten into your home

Make sure your new cat or kitten:

  • Has been tested for FELV (feline leukemia virus) and FIV (feline immunodeficiency virus). These are diseases that can be transmitted to your existing cat … and put your kitty at risk.
  • Gets a physical exam. It can help you make a more educated adoption or purchase decision. That way, you don’t bring a cat or kitten into your home that could have issues, such as an infectious illness.

Also, make sure your existing cat is up-to-date on his or her shots, including rabies and feline distemper.

Finally, you’ll want to make sure your cats are spayed (females) or neutered (males).

Most shelters take care of this as part of their services, but always ask.

You’ll have more issues with cats marking their territory in your home if you have male cats that are not neutered.

If you’re getting a new kitten…

Keep in mind that kittens don’t have a fully-developed immune system yet.

It’s likely your kitten won’t have all of his or her kitten vaccinations.

This means kittens can pose a higher risk of disease to your existing cat (and to themselves).

Typically, kittens are fully vaccinated around 16 weeks of age.

If your kitten is sick, you may need to put your kitten on a longer “quarantine” from interactions with your existing cat.

We encourage you to chat with our vets about that. Each situation is a little different.

On a positive note, kittens tend to be more tolerant of change compared to adult cats.

So hopefully, the introduction between your cats will go smoother!

Related articles:


Make sure your new cat is healthy

If you’re getting your cat from a rescue group or local shelter, your first exam is free within 14 days of adoption.

Call our Castle Rock veterinarians at 303-688-3757 or:

Book your visit here 

Cherished Companions Animal Clinic is a veterinary clinic in Castle Rock, Colorado. Specializing in the care of cats and dogs, our goal is to help you and your pet feel more comfortable, keeping your stress to a minimum.

This article is intended to provide general guidance on how to introduce a second cat or kitten… with as little drama as possible. If you have specific questions or concerns, please contact your local veterinarian. (If you live in or around Castle Rock, we welcome your call.)

© 2018, Cherished Companions Animal Clinic

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