Cat Hissing at a New Kitten

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  • Updated on: 11/02/2020

Even if your feline buddy is very affectionate and sociable, you should not expect that he will become more friendly towards other animals with aging. The cat’s instincts and character do not change, his habits take root, and cats are very reluctant to change them.

A successful introduction of a new feline to your grown-up cat is a daunting task, and in many respects, it depends on the older cat’s age. The ideal age for joint adaptation of two felines in the house is up to 3 years, make an adult cat get along with another grown-up feline is much more difficult. With aging, it will be harder for a cat to accept new living conditions. But despair: there are no hopeless situations in this case. The main thing is to find the right approach to how to train your existing cat to accept a new fur baby, and your feline companions will live in full harmony.

why my cat hissing at new kitten@grooveriderz / FreePik

Why is Your Older Cat Hissing at a New Kitten?

1. Disrupted daily routine can cause your cat to feel uneasy

Cats like to be in the driver’s seat! They hate changes, so they may feel unsettled because of newcomers. Make sure you share your attention with your feline friends – cat parents may need to give their grown-up cat more attention than usual.

If your cat feels uneasy, he may hiss, growl, or show other signs of aggression. Keep your cat’s schedule as close to his daily routine as possible so that the only change he will experience is a new fur baby. Your adult cat will feel much better if he feels in control of his surroundings [1].

2. Your cat doesn’t want to share his space with a new kitten

Your grown-up cat has been master of the house for a while; he is used to doing things his way, and when you add a second feline to the family, he may refuse to share his pad with the newcomer. You should have enough resources for your fur babies; install one litter box per cat, with one additional, in different places. Make sure that your older cat doesn’t show unhappiness by relieving himself outside the box. Each cat needs access to his own food, water, cat tree, and litter box – they will also love to have their own toys and hide-out and napping spots![2]

3. Your cats may be of the same gender, or your resident cat may not accept a new feline for his playfulness

Some felines may resent each other because they have the same gender. If your pets are both males, they are highly likely to become aggressive to each other [3]. However, the resident cat is the first one who starts showing aggression.

Also, your grown-up cat may resist the newcomer because he doesn’t like his active and playful nature. Before taking home a new fluff ball, make sure that he is compatible with your cat. Older felines usually don’t want to accept a new mischievous kitten.

READ MORE: How much does taking Care of a Cat Cost

how to make adult cat and kitten get alongImage by Adina Voicu from Pixabay

READ MORE: Signs Your Cat Loves You

How To Train Grown-up Cat to Accept a New Kitten

While your cats may never become best friends, most domestic cats, although they have solitary nature, still find ways to be on good terms. Some may even behave like littermates in the long run, but you should arm yourself with patience. Here are several tips on how to introduce a new kitty to your resident cat.

1. Keep your cats segregated at first 

Don’t throw your new kitten directly into the mix. This will scare the kitten and make your resident cat angry. Instead, keep them separately where they can observe each other from a safe distance. Make sure they have their own litter box, bed, bowl, and toys. This adaptation period will help your feline companions get used to each others’ scents and will keep the environment peaceful.[4]

2. Mingle your cats’ scents

Smells play a significant role in the cat world. Your existing cat may resent a newcomer because he has a strange, unfamiliar scent. By mingling odors, you can help your resident cat to accept a new fur baby much faster. Here are some ways:

  • Switch their beds. The bed retains the cat’s smell. By switching the beds, you will mingle their scents.
  • Wipe the new kitten with a wet towel, then wipe the resident cat with the same towel. This trick will make the cat smell someone else’s scent, and he quickly adapts to it.

3. Allow your cats to meet while segregated

After about a week, try moving on to the next step, allowing cats to see and sniff each other through a partition. Don’t leave them alone. Each cat has its own temperament. You cannot predict how your four-legged friend will react to the baby. Some show curiosity and quickly become friendly. But the majority shows indifference or even aggression to a newcomer. Make sure that the existing cat does not harm or frighten the new kitten.

If the housecat hisses at the kitten, this is normal behavior. Let the pets observe each other from a distance. But if he goes on the offensive, strives to scratch or bite the new kitty, interrupt the acquaintance. You may need to keep your cats separated a bit longer before finally bringing them together.

4. Give each cat separate facilities

Once you’ve put both fluff balls together in a shared surrounding, don’t force them to get close. Ensure they each have their own bed and not next to each other, two bowls, and litter boxes in different parts of your home.

This will reduce stress and allow each cat to feel independent so they can become friends when they are really ready. If your cats feel they have control over the situation, they are much more likely to give you the positive results you expect.[5]

READ MORE: How to Help Cats and Dogs Get Along

how to stop adult cat from hissing at new kittenPhoto by Nicole Vandale on Unsplash

The Bottom Line

Don’t worry if your feline companions do not get along. Sometimes cats do not accept each other for several months, and then they yearn even from a short separation.

Article Sources:

  1. Turner, Dennis. “The Domestic Cat.” Cambridge Core,
  2. Stella, Judi. “Effects of Stressors on the Behavior and Physiology of Domestic Cats.” PubMed Central (PMC), 31 Jan. 2013,
  3. “My Cat Is Being Aggressive towards My Other Cat, What Should I Do?” RSPCA Australia, 30 Apr. 2019,
  4. Cohen, Hsin-Yi. “Introducing a Kitten to Other Cats.” Safer Pets, 30 Aug. 2020,
  5. “Aggression Between Cats in Your Household.” ASPCA,

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