How To Introduce Your New Kitten To An Older Cat

First impressions are SO important 😻

When Alyssa Fleck decided to adopt a stray kitten named Limoncello, she knew it wouldn’t be easy for her 7-year-old cat, Portabella.

Transitioning from only child to sibling can be tough. Learning to not only share your space, but your parent’s love and attention can take some getting used to — and the same goes if you have whiskers and fur.

Pet parents wondering how to introduce a new kitten to a cat will find it’s not a process that can be rushed. Portabella was not too keen on having a new furry playmate to contend with, so Fleck turned to her colleagues at the American Society for the Prevention of Cruelty to Animals (ASPCA) for advice.

“After five years of Portabella being the only pet in the home, I knew it wasn’t going to be a quick and easy adjustment, but I was committed to making it work,” Fleck, media and communications manager at ASPCA, tells The Dodo. “Among many suggestions and recommendations, ‘patience’ was the most important. Successfully introducing two cats, in many cases, is not going to happen overnight.”

In some special instances, cats and kittens can form bonds immediately — such was the case with 10-year-old Mason and his five foster kittens, Scrammy, Moo Shu, Florentine, Hatch and Fabergé (pictured below).  

Mason and one of his foster kittens | TinyKittens

Introducing a new kitten to an older cat should be done slowly and with care, explains Christina Lee, animal behavior counselor for the ASPCA’s Anti-Cruelty Behavior Team. “Cats are naturally solitary animals — free-ranging cats are territorial, and hunt and scavenge for food alone,” Lee tells The Dodo. “Owners should be aware of this so they don’t get discouraged when it takes a while for the resident cat to get used to a kitten!”

Before making a commitment, pet owners should consider whether the kitten in question will be a good match for their cat — especially where energy levels and personality are concerned. “If the resident cat is a senior cat and prefers to be left alone most of the day, the owner should consider whether the resident cat would appreciate an energetic kitten bouncing off the walls,” Lee says. Pet owners should also be sure they have the time to give the kitten appropriate outlets for their energy, notes Lee, as well as space in their house for another litter box.

Portabella (top) and Limoncello (bottom) | Alyssa Fleck

To ensure that the cats’ personalities will mesh, speaking with a professional is a good way to go. “I would recommend going to an animal shelter where you can speak with a behavior counselor who can share information with you about each available cat’s personality, and whether they would be a good fit in a multi-cat residence,” Fleck says.

So what should cat lovers do once they decide to finally expand their feline family? Here’s how to introduce your cat and kitten safely so they will become best buds:

Separate the cat and kitten, at least at first

Limoncello stayed in the bathroom at first | Alyssa Fleck

Before bringing their new kitten home, pet owners should create a separate “territory” for each cat, complete with everything they need. “Owners should designate a separate room that can be closed off for the new cat — an unoccupied bedroom or a bathroom are good options,” Lee advises. “The new cat should have its own litter box, bedding, toys, and water and food bowls in its room.” This initial part of the process should last for at least a few days, but can sometimes continue for weeks or even months, notes Lee, “depending on how the introductions go.”

As the cats acclimate to the new situation, it’s important to watch out for signs of stress and anxiety, notes Dr. Sheila Segurson in a release by the Best Friends Animal Society. These signs can include “hiding, aggressive behavior, decreased appetite, and/or excessive vocalization” and if they continue for more than a few days, a veterinarian should be consulted.

One way to help your cat through this transition is with consistency. “Try to keep as many aspects of the resident cat’s routine in place so that the resident cat does not get too stressed out. Avoid making too many changes at once,” Lee adds.

Get your cat used to the kitten’s scent (and vice versa)

Limoncello enjoys some time outside the bathroom | Alyssa Fleck

Once both cats seem comfy and cozy in their new spaces, they can start getting to know each other in a passive manner. “This means the cats should be able to hear and smell each other, but not see or touch each other,” Lee explains. A few ways to get them used to each other’s presence is by setting up a dinner date for the two of them, feeding them at the same time on either side of the closed door. This helps them associate tasty food with the presence of the other cat, Lee notes. Pet owners can also play with the cats on either side of the closed door, encouraging them to paw at the space underneath the door (which may evolve into positive play with each other down the road).

After a few days have passed, pet owners can switch the cats’ rooms so they can become accustomed to each other’s scent and belongings, while exploring a new territory. Cats gather an astounding amount of information about the world and each other with a single sniff. “Cats have glands in their cheeks that produce pheromones,” Segurson says, “chemical substances that can help relieve anxiety and provide information about the cat who is producing the pheromones.”

Lee encourages pet owners to gently rub a towel on their resident cat’s cheek and then bring it into the other room, and rub it on their kitten. Afterward, bring the towel back to the resident cat as another way to introduce them.

Introduce them visually

Portabella and Limoncello share a supervised meal | Alyssa Fleck

If passive introductions go smoothly, the two cats can finally get a look at what’s behind the door — at a distance, that is.

Lee recommends setting up a baby gate in place of a closed door as a comforting barrier. “Play with or give yummy treats to each cat while on either side of the baby gate, and recruit a family member or friend to help you so that both cats are occupied,” Lee says. “When the cats seem relaxed after these exercises, you can allow them to be near each other without a barrier.”

Allow for some supervised playtime

Alyssa Fleck

“Start off with short sessions and gradually increase the amount of time they are together,” Lee recommends. However, if either of the cats seems stressed or displays aggressive behavior (hissing, growling, swatting), take a step back in the process. Under no circumstance should the owner let the cats “fight it out,” Lee says. “Keep in mind that the introduction can take anywhere from a few days to many months so go at your cats’ pace!”

Fleck has found this particularly helpful with her kitten, Limoncello, and cat, Portabella. “If the two cats are having positive experiences while within close proximity to one another, they’re learning to coexist and — hopefully — see the other cat as less of a threat,” Fleck says.

Of course, positive reinforcements of good behavior always help. “After a few minutes of the two spending time near one another like this, I’ll be sure to give them a treat to reward the good behavior!” Fleck says. “I also make sure Portabella always has a place to escape to — like a shelf that’s too high for the kitten to get to, so she can observe what’s going on in peace.”

Know that it’s going to take time — and that’s OK

Alyssa Fleck

“The slower you go the better," Lee notes. “However, there is a chance that cats will merely learn to live with each other and share the same house.” If you run into serious issues along the way and need extra help, Lee recommends pet owners reach out to a behavior expert, such as a certified applied animal behaviorist (CAAB or ACAAB) or a board-certified veterinary behaviorist.

As for Limoncello and Portabella, it's been a month since bringing the kitten home from the ASPCA Adoption Center and Fleck is still giving the two time to warm up to one another. “While Portabella is very curious about Limoncello, she still values her personal space — a difficult thing to come by when a kitten is running around playing with everything in sight,” Fleck says. “For now, I still keep the cats separated when I am not home to keep an eye on them, but I am increasing the amount of time they spend in the same room and working toward the day they can — at the very least — tolerate one another.”

Though it would be nice if the two were best friends, Fleck is content with Portabella and Limoncello simply getting along. “I’m not sure if they’ll ever snuggle up on the couch licking one another, but with a slow introduction and some patience, I am confident they’ll happily coexist in the same home soon enough.”