Warning Signs to Know When Introducing Cats

Are you planning on introducing a new kitten or cat member to your family? You may be worried about your cat’s reaction to the new member. How are they going to interact and bond with each other? Well, cats have a different way of bonding and assessing each other’s appearance based on first impressions. Unlike humans, cats can’t fake happiness when greeting someone they will not like. So what should you do in such cases?

It is simple; you need to know that warning signs can indicate to you if your cat is not going to take well to the new member. This is especially important if you bring in a kitten and have an adult female or male cat present in the house. It can prevent your cats from fighting with each other which can react to a ruckus in your house.

Warning Signs to Know When Introducing Cats

Cats cannot bring themselves to trust others easily, be it humans or other cats. Some cats can easily open up and get comfortable with kittens or other adult cats. However, some cats are possessive and they might not be willing to share your attention with the new member.

Warning Signs to Know When Introducing Cats

So here are some warning signs to know when introducing cats to each other.

Your Cat Starts Hissing, Snarling, Rumbling, or Growling

Your resident may start making strange sounds that emit it is displeased or feels angry at the presence of a new feline member. Cats are territorial creatures, and hence, for them seeing a new cat or kitten rings alarm bells. You can sense a cat’s displeasure by the different types of sounds made.

Hissing or Snarling

If your cat is making a hissing sound, do not be immediately alarmed by it. Hissing is quite common in cats, and you may notice them doing this on any new toy or accessory you buy for them. Cats tend to hiss when they do not understand something new. However, do take this as a warning sign because when your cat hisses, it means they don’t want the other cat to come closer to them or to their area (which is your home).

So you may want to not bring the other cat near them otherwise, there would be an inevitable cat brawl.


If your cat is rumbling and hissing, it means that they are vocalizing their displeasure towards you for bringing another cat to the house. That means it is a warning sign for your new feline member and for you to be careful. However, it can also be that your cat is just hungry and the rumbling indicates their hunger. So if a new cast member is introduced when they are hungry and your resident cat rumbles, don’t be alarmed. Try taking your resident cat first towards their food bowl.


Hissing is usually followed by growling because they have an internal fear of losing out on you and dedicate their entire attention to the new cat. It is similar to how the first child might react to a newborn who is their younger sibling. As a result, picking up your resident cat and giving them due attention can calm them down. Alternatively, making your cats socialize with each other by having food bowls next to each other can remove this warning sign.

Changes in their Body Language

Another way that your cats will verbalize their discontentment on having another cat introduced to them is through changes in their body language. You have to be careful and note down a change in their physical behavior if they are not making any kind of sounds. A cat’s body language can give you many indications about their behavior. Here are some things that cats are likely to do, warning signs for you to take note of.

Flattening the Ears

This is one warning sign that you might have noticed your cat do when it is gazing at birds by the window, and it flattens its ears to not let them get suspicious. Similarly, if your cat is flattening its ears when it sees a new feline member, then just maybe not leave the new cat alone with your resident cat. That is one indication of your resident cat preparing to attack.

Dilating the Pupils

Cats also tend to dilate their pupils in a fury, which is a huge red flag and a warning sign for you to take your new feline pet elsewhere and away from your cat’s furious gaze. After all, cats are territorial creatures, and you wouldn’t want your new pet to get injured by the resident cat. This is one warning sign that maybe keeping your new pet in a different space is the best option because the resident cat is not ready to interact with them.

Puffing Up their Fur

Alternatively, with flattening the ears, your cat also puffs up their fur to create a hierarchy where they are at the top. This is common in the animal kingdom, where puffing up fur is the animal equivalent of squaring their shoulders to put the other cat or person down.  So you can notice this trait when your cat’s tail becomes bushy, or their body’s fur strands are raised. So if your new pet is not dominant or is younger than the resident cat, it may cause the new pet to be scared away and develop fear.

Our Final Thoughts

You may have noticed at least one of these warning signs in your cats if you happen to introduce them to a new feline member or see them interacting with some feral or stray cats. Slowly introduce your cats to the new member of the family. Keep the new cat in a separate part of the house, so it has minimal interaction with the resident cat; create a new base camp for the new member. This is a mandatory isolation period that cannot be avoided.

So the next time you plan on bringing a kitten or cat home, be careful of these warning signs to know when introducing cats.

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