Cat Hissing At a New Kitten

Cat Hissing At New Kitten

A cat may hiss at the new kitten because she is expressing territorial aggression, feeling unsettled, and unwilling to share her space. This is normal cat behavior when there is a new kitten in the household and can best be addressed by properly introducing the cats to each other.  

Why is your cat hissing at the new kitten?

A cat growling at new kitten is usually the scenario especially if the resident cat has gotten used to being the center of attention. However, there are also cases where a cat and a new kitten will instantly bond with each other. Each cat is unique and has its personality. If your cat resents the new kitten that you just adopted from a pet shelter you should not panic since it is natural cat behavior. It only needs a  proper introduction of the cats, coupled with lots of patience. Here are some common reasons why your cat is hissing or growling at the new kitten:

1. Your cat feels unsettled because of her disrupted routine

Your cat may be hissing at the new kitten because she finds the new kitten as a threat. Cats are creatures of habit and they follow a pattern each day because routine for them is everything. So, when a new kitten arrives, it follows that everything will be disrupted because of the additional occupant in the household.  As a result, your cat will feel unsettled and indifferent towards the new kitten, hence, the negative behavior like growling and hissing. 

2. She does not want to share her space with a newcomer

Your feline may be manifesting territorial aggression towards the new kitten that’s why she’s hissing at the newcomer.  This type of aggression occurs when a cat feels that her territory has been invaded by a trespasser. It usually happens if your cat is the only cat in the household and has become so used to being the “apple of everyone’s eyes”.

She is reluctant to share her space and that is why your cat is reacting negatively to the newcomer. You can address this by having separate resources for your cat and the new kitten such as their own scratching post, food dish, water bowl, and litter box. Each cat should have an extra litter box in a separate area, too, as well as their appointed sleeping area and favorite toys. 

3. Your cat and the new kitten may have the same gender or your older  cat may resent the new kitten for its playfulness

Some cats do not meet eye to eye because they are of the same gender. If your cat and the new kitten are both males, there is a higher tendency for each other to become aggressive. However, it is usually the resident cat that is the aggressor or the bully.

Similarly, your older cat may dislike the new kitten because she resents its active and playful nature. Before considering adopting or bringing home a new kitten, ensure that it’s compatible with the resident feline. Cats that are older and used to the single cat arrangement are usually reluctant to accept a new kitten that is active, has boundless energy, and is playful.  

your cat and the new kitten may have the same gender
Image: / Ana-O

4. It may be due to your cat’s temperament

Cats and kittens have unique characters and temperaments just as humans do which is why aggressive behavior is to be expected at the first meeting. A proper introduction is key to helping them adjust well to each other. If your older cat is being aggressive to the new kitten then call her attention at once and separate them from each other but do not punish her. Instead, make sure that each one has access to their resources and space in the house.

How to introduce a new kitten to your older cat?

Preparing for the arrival of a new kitten plays an essential role in determining the outcome and reaction of your older cat. If both cats are properly introduced, there is a lesser tendency for aggression. Before bringing her home, try to observe the new kitten’s personality, and assess if she will be compatible and will get along with your resident cat.  

Here are some tips on how you should introduce a new kitten to your older cat:

Prepare your older cat and create a relaxing environment for her.

Even though the new kitten has not arrived yet, you should already prepare your resident cat for the newcomer. See to it that she’s in tip-top form and has a clean bill of health. Bring her to the vet for a thorough checkup and make sure that she has been given her vaccines as scheduled. Ask for your vet’s advice if a nutritional supplement is needed for her to have a calm composure. Use a Feliway diffuser in your home to create a relaxing ambiance for your resident cat in preparation for the coming of the new kitten. 

Prepare for the new kitten’s arrival. 

You should prepare your home at least one week before the new kitten’s arrival. Place the necessary resources such as her food bowl, water dish, litter box, bed, and toys in a designated space. Let your older cat smell them so she will familiarize herself with the scents. You may also put in some items that have the new kitten’s scent such as a blanket she sleeps in and you can request this from the shelter where she came from.

While doing the preparations, make sure that you’re also prepared with the coming new kitten because if you feel stressed your older cat will detect it and will also be negatively affected. 

Prepare for the new kitten’s arrival. 
Image: / Creative Credit

Introduce each other by smell first. 

On the arrival day, allow your senior cat to stay in a separate room so she is not able to see the newcomer. This will give you time to introduce the new environment to the kitten who will pick up the smells in the house quickly and become aware of another cat’s presence. After a quick introduction to the surroundings, you can swap them and allow the older cat to wander around the rooms where the new kitten has been so she can detect the kitten’s scent.  

Let them have visual contact with each other.

After the older cat and new kitten have gotten used to their scents, it’s time for them to see each other. However, they should be separated by a screen, a door gap, or a glass partition. Let them become comfortable with each other and they may even sniff noses or rub their bodies against the partition.  If they are behaving this way then they are ready to meet each other face to face. 

Be patient and keep initial introductions short. 

Keep the initial introduction short but meaningful. During this time, both are already familiarized with their scents which will help a lot in decreasing the instances of aggressive behavior. However, if there are hissing and growling then usher them to separate rooms. Be observant of their body language and be ready should aggression set in. 

Don’t scrimp on praises and treats.

It is normal for the cats to not accept each other easily so do not get too worried. Patience is key as these things take time. During the entire introduction process, be generous with your praises for the cats, especially your resident cat. This will assure her that she is not being taken for granted or replaced and instead she is given a new playmate and buddy. Give them treats during the process and give them time to get used to each other. 

The introduction process should not be done in haste. Be watchful and observant as the older cat and the new kitten start to spend more time together. Even if there will be no more hissing or cat growling at the new kitten,  there may still be instances when the older cat will be aggressive. Keep to a specific routine when it comes to sleeping, feeding, and playtime because cats are sticklers for routine. 


If your cat is hissing at the new kitten then do not panic or worry as it is considered a normal cat behavior. It takes time to adjust to each other and for older cats that are used to being the center of attention, having a new kitten is not easy to accept and handle.  However, this can be addressed with the proper introduction coupled with your patience and tender loving care for both of them. 

Also, check out our article on how to get a cat to stop hissing.