My cat does not accept the new kitten who has just arrived home, what to do with a cat jealous of a kitten ? This is the problem I faced when my little kitten came to our house. Indeed, my cat Mistee was already an adult when we adopted our new kitten Licorice. And it was complicated to get the two cats get along !
In fact, for make an adult cat accept a new kitten and vice versa make a cat accept a kitten, I learned that you have to go through integration steps:
- Know how to managearrival of a kitten with a cat ;
- Savoir integrate the kitten into a cat's territory ;
- Know how to react when the cat attacks the kitten Or vice versa ;
- What to do when faced with a cat who is afraid of the new cat.
Here is what I learned for get the two cats to accept each other and live together without the cat attacks the kitten and therefore without a fight at home!

Arrival of a kitten with an adult cat
If you already have an adult cat at home and you are going to adopt a small kitten, it is essential to properly organize the kitten's arrival at home so that their first meeting takes place in the best conditions:
New kitten with adult cat at home
Because cats are territorial animals, it's very rare for an adult cat to readily accept the arrival of another cat, kitten, or animal into your home. In effect, your home has become your cat's territory. However, the arrival of a new cat (adult or kitten) is necessarily disturbing for him who has lived there alone until now. He will not stand a new kitten encroaching on his territory!
And it's even worse if your cat is old or if it has never shared its territory with other animals or cats. See my article: Can an adult cat kill a kitten?
New kitten with adult cat - Patience
So, to prevent your cat from attacking your kitten, above all, don't put them together in the same room immediately. Indeed, it will be necessary to avoid territorial wars and to ensure that the division of the territory is done little by little and amicably!
In fact, for the cohabitation between your kitten and your adult cat is going for the best, it will be better to separate them at the beginning and teach them to share their territory gradually.
Arrival of a kitten - First meeting
When you arrive home on the 1st day, it will be best to put your kitten in a transport crate and leave it inside for its first meeting with your adult cat. Your cat must remain free to move around.
Sit in the room where your adult cat is, keeping your kitten's cage closed. Be patient and wait for your adult cat to approach the crate and start smelling your kitten.
- If you see that your adult cat is not aggressive at all, you can try to open the crate and let your kitten out. Thus, they will get to know each other and accept each other (or not…);
- On the other hand, if you observe that your adult cat does not accept the kitten, then do not insist because it will have to be gradually accustomed to it over several days. For this, you will have to represent your kitten in its cage in the same way to your cat and day by day, your cat will get used to the presence of the kitten. You can then open the cage and leave them together.
Arrival of a kitten - Sharing territory
For the first days and the first nights after their first meeting, I therefore recommend that you put your kitten away from your cat. Thus, it is you who will orchestrate the moments when they will meet again. You will be able to control, if necessary, aggressive behavior and encourage them to accept themselves calmly and respectfully.
Everyone has their own room for 1 week
To avoid conflicts and fights which could be dangerous for both your kitten and your adult cat, I advise you to install your cat and your kitten in separate rooms (see how to welcome a 2 month old kitten?).
Shared spaces by following
As soon as they get used to their presence, you can leave them free in your house as long as they are separated by a barrier or an obstacle. Thus, your cat and your kitten will be able to come into contact but without direct confrontation.
Here is a practical barrier to let your kitten run free in your home without risking your cat attacking it:

Home sharing
The acceptance period is different depending on the cats. It is therefore you who will judge whether it is time to let your cat and your kitten free to come and go together in your house.
However, it will be better to plan a emergency exit for one or the other. Indeed, if your cat attacks your kitten or vice versa, the cats must have an escape route to escape (door open to the outside or to another room, perch in height…).
Separate bowls and litter boxes
For meals, they should not be given food and drink on the side. Indeed, each must have his own place where the bowls and litter are placed. Initially, they must be able to go to eat or do their needs with confidence knowing that they are in their respective territories.
If unfortunately you find that your cat starts urinating all over your houseis that there is a problem and that the cohabitation between kitten and adult cat is not yet well established ...

My kitten does not accept my cat - Why?
In general it is the reverse: the adult cat does not accept the new kitten. However, it happens especially in kittens who have been separated from their mother too soon that it is they who do not accept the resident adult cat.
Indeed, if your kitten was removed too young from its mother, it will not have been weaned properly and will not have acquired all the socialization skills it needs until its 3 months. He can then have behavioral problems and even be emotionally and socially unbalanced. Suddenly, the kitten will fear an adult cat and behave aggressively towards him.
My cat is not accepting the new kitten - Why?

Aggressive cat with kitten - By rejection
You have to realize that your adult cat is the one with the most seniority in your home. It is with you but especially with him that an intruder arrives. It is therefore normal that your cat does not want to share his territory and give way to a new one.
Aggressive cat with kitten - Mood incompatibility
If your cat doesn't seem to want to live with your new kitten, it may just be because he doesn't like her. Just like us, we can't get along well with everyone, depending on the characters of the cats, not all are going to be buddy pals!
Aggressive cat with kitten - Out of jealousy
If you have just adopted a kitten in your home, you will inevitably devote time to it and give it affection. And without realizing it, you will change the habits you had with your adult cat ...
Maybe you will play with him less, postpone his meal times, change his rooms, or deny him access to certain areas of the house.
However, a cat is an animal that functions according to habits and routine. And, it will suffice that you pay him a little less attention than usual in favor of a kitten for your cat seems jealous!
Cat jealous of a kitten?
If your cat is isolated, hiding, no longer comes to be cuddled since your kitten has joined your house, it is obviously in reaction to the arrival of your kitten. All of these behaviors make you think that your cat is jealous of your kitten but is it really jealousy?
In fact, if it is true that a cat experiences emotions (joy, well-being, fear, stress ...), it would seem that he does not experience feelings like those experienced by humans (love, jealousy , remorse, despair…). And just like a cat does not cry like a human being can do it, a cat does not feel jealousy like us.
Generally, when we say that a cat is jealous of a new kitten, it is in fact simply that he does not accept the arrival of the kitten. Indeed, the cat does not accept the changes of habits in his daily life which are linked to this new kitten!
Cat jealous of a kitten - Why?
It happens (quite rarely, however) that a cat develops the hyperattachment syndrome towards his master. This is a very strong bond that forms between the cat and its owner when they have a close relationship. In this case, the arrival of a kitten, a baby, a roommate, another pet can cause reactions that resemble jealousy. See my article: Close relationship with your cat: Danger !
How to make an adult cat accept a kitten?
It will take several days and sometimes several weeks before you manage to get a kitten to be accepted by an adult cat. You will need to be patient! Let the kitten and the adult cat get used to each other at their own pace and above all, don't force them!

Allow time
It will be necessary to increase day by day the time they will be together, let them approach, feel, tame with the help of the separation barrier as indicated above " Arrival of a kitten - Sharing territory" page (in French).
Avoid them fighting
If after a few weeks your cat is still aggressive towards your kitten, if they start to fight, then we have to create a diversion! You may clap your hands or make a loud noise to distract their attention. Do not try to intervene between them because they must be able to manage their relationship without mediation.
Mix their smells
For the 2 cats to accept each other better, exchange their blankets so that they get used to their smells respectively.
Play with the 2 cats together
As soon as the cat manages to accept the kitten in the same room as him, enjoy playing with them both by offering them the toy and taking them in turns.
Diffuse pheromones
To limit aggressive behavior, it is necessary to reduce the state of stress in cats. The most effective way for a cat to feel calmer, more peaceful in the face of a stressful situation for him, is to diffuse pheromones.
I therefore recommend that you plug in a pheromone diffuser where the adult cat and kitten will meet. Thus, cats will be much calmer and accept each other much more easily and less aggressively!
Cut the cat's claws
If there is a fight, your adult cat can hurt your kitten if they attack and scratch it. So, since prevention is better than cure, to avoid any deep scratching, it will be better if your cat's nails are cut (see How to cut a cat's claws?).
My cat does not accept the new kitten - Sterilization
Finally, my little Mistee (female) came to accept my little Licorice (male kitten). It was long but I think easier than if it were a male adult cat with a male kitten.
Indeed, cats of opposite sexes accept each other better. There is a stronger and more important rivalry between two male cats than with two cats of different sexes and even with two female cats together.
I have read on the Internet that sterilization can calm adult male cats and therefore allow better cohabitation with a male kitten. But I'm just reporting info because I haven't checked myself ...