How to spot the warning signs when introducing cats

Updated 15/11/2024

So, you’ve decided to add another furry feline to your household – what could go wrong, right? Well, before you start dreaming of double the cuddles and synchronized purrs, remember that your resident kitty might not be rolling out the red carpet just yet. Yep, your current cat could be less than impressed about a new roomie, and that’s why it’s important to keep an eye out for warning signs when introducing cats.

Key takeaways

• Take any new cat introduction nice and slow.
• Keep things on a positive note with plenty of praise, pats, treats, and love.
• Watch for any warning signs of potential cat-astrophes.

How to introduce cats 

Cats aren’t exactly the most social creatures, and unlike dogs, they tend to prefer spending time alone. This means that when you bring your new cat home, your resident kitty might feel like their territory (and your attention) is under threat – you’d be quite put off if someone barged into your house uninvited, too. So how do you introduce cats to each other? Follow this step by step guide on how to keep the peace.

Adopt a young cat

Kittens and young cats often seem less threatening to older, established cats. Think of them as the cat world’s equivalent of a younger sibling – annoying at times, but not a serious contender for dominance.

Make sure everyone’s neutered/spayed

Nothing stirs up territorial disputes like hormones, so ensure all your furry friends are spayed or neutered. This not only reduces the chances of a catfight but also keeps everyone healthier.

Separate your cats for the first few weeks

“Quarantining” your new feline family member is a crucial part of the cat introduction process. Set up your new kitty in a separate room where they won’t cross paths with your current cat. Make sure they have all the essentials – food, water, a litter box, toys, a bed, and plenty of cozy spots to hide. During this time, the goal is for both cats to get used to each other’s presence without the added stress of a face-to-face encounter. For it to work, the kitties mustn’t lay eyes on each other during this phase.

Need to be away during this important period? Consider getting a reliable cat sitter who can ensure your kitties are well taken care of in your absence. Your loving, in-home cat sitter will help maintain their separate spaces and manage your furry friends’ needs so you have total peace of mind while you’re away.

Swap their scents 

Our furry friends rely heavily on scent, so introducing two cats to each other’s smell before meeting can make the whole process a lot smoother. Try giving each cat a blanket or a toy the other one has been using.

If you’re feeling adventurous, some pet parents suggest swapping the cat’s spaces (just make sure they don’t run into each other in the process!). The idea is that you move the new kitty to another room and close the door, then let your resident cat sniff out the room they were just in. Next, you should shut this door and allow your new furry friend to explore the rest of the home. It’s a good idea if you’ve got the space, just make sure the two cats don’t come across each other!

Make sure there’s enough to go round

Sharing might be caring for humans, but not so much for cats. To keep the peace, make sure each cat has their own litter box (plus an extra one for good measure), bed, toys, scratching posts, and feeding station. This way, no one feels like they have to compete for resources.

Introduce your cats to each other through a barrier 

When it’s finally time for your cats to “meet,” keep a barrier between them – a glass door or a baby gate will work well. This allows them to see each other without any risk of a physical fight. Keep things positive by offering treats and gentle encouragement, and if all goes well, try feeding them on opposite sides of the barrier to reinforce that neither is a threat to the other’s food supply.

Let them meet face-to-face

If everything’s going according to plan, it’s time to let them meet in person (or cat?) for a little face-to-face introduction. Start with short and sweet sessions loaded with plenty of treats and positive reinforcement. It’s always a good idea to have a backup plan (and an extra pair of hands) in case things don’t go as smoothly as you’d like. 

Good signs when introducing cats include them appearing relaxed and comfortable with each other. Look out for signs your cat is accepting the new kitten, such as grooming, playing together, and even co-sleeping – these are all great indicators that things are heading in the right direction!

But what about the flip side?

Warning signs when introducing cats

Even with the best intentions, sometimes kitties just don’t warm to each other. Here are some telltale signs that your furry felines might not be ready for a fully-fledged friendship just yet:

Dilated pupils

Big, round eyes can indicate fear, anxiety, or overstimulation.

The staring contest

If your furry friends are locking eyes without blinking, it might be a showdown for dominance.

Flattened ears

Flat ears mean your purr pal is either scared or ready to pounce.

A swishing tail

If that tail’s swishing like a windshield wiper, it’s a sign your cat’s not happy.

Puffed out fur

If your cat’s looking twice their size, their stress levels are probably through the roof because they’re feeling threatened.

Overall body language

Cats use their whole body to express how they’re feeling. If a cat is unhappy, you might see them stiffen up or arch their back like a Halloween cat. When they’re in defense mode, they’ll try to make themselves as small as possible, often flattening their body and tucking their tail away.

Swatting

This aggressive behavior your cat is ready to fight, and it’s a major red flag.

Hiding

Cats tend to hide when they’re scared or overwhelmed.

Hissing

Cats hiss when they’re feeling threatened or scared. It’s quite common to hear a new cat hissing at other cats for a few seconds when they first meet, but if it continues, it’s a sign you need to separate the kitties.

Growling

Yes, cats growl too, and it means they want to be left alone.

Loud vocalizations

Yowling or howling? It’s time to separate the cats ASAP.

When introducing cats to each other, remember to never force the process – just like people, cats need time to warm up to new relationships. If tensions rise, simply take a step back and try again later. It’s much easier to go slow and steady from the beginning than to fix a relationship that’s started off on the wrong paw.  

Meet our veterinary expert, Corinne

This article has been checked by veterinarian Corinne Wigfall BVMBVS(Hons) BVMedSci(Hons). Corinne is originally from Wales and moved to New Zealand after graduating university. She started her career with a university based equine internship and moved onto mixed and small animal practice. Currently she splits her time between online tele triage and working in an after hours vet clinic.