It really varies. I think the biggest factor is the personalities of the cats. I've got one who loves everyone and accepts whatever cats/dogs/kids/fosters/anything we bring home without question. I have another who pretty much hates everything and she spends half her time growling at some thing or other. *Generally* I'd say 2-4 weeks is a good average adjustment time. But outside that range isn't uncommon.

 

Mine tolerated each other pretty much immediately, but I adopted them only about 1 month apart. Alas, they're still at "tolerate" after nearly 11 years.

 

It depends on the cat. I'd say two weeks to two months, and some never move past tollerate. I have four and my youngest two, Tiger (1 year old) and Cheddar Biscuit (3 month old kitten), are besties after just a couple of weeks. They play alot and I caught them cuddling tonight. Tiger and Zoey (2 years old) also got along quickly, they play sometimes but don't cuddle. Muffin (7 years old) barely tollerates Tiger after a year but is ok with Zoey and the kitten, and Zoey currently hates the kitten, even though she gets along fine with the others.

In general, Muffin is kind of a bully, Tiger is my welcome wagon (with my fosters too), Zoey is a people cat and I suspect she hates the kitten because he is always all over me and that's kinda her job, and the kitten is just a sweetie.

 

It varies dramatically - I was really lucky with the ones I have now - in fact Baz and Becky were instant best friends with Oz and Jem. The Princess Tramp adopted them as hers (as she had with Oz and Jem before them). Lottie tolerates them - sometimes even allows them to groom her but is not that interested and chooses to be be more aloof from the crowd!

 

2 weeks with both introductions. I have three young, unrelated cats. I kept them separate for one week, and spent the second week letting them see each other and sniff each other through a cracked door and then visit for brief periods. I think I wound up with three pretty social cats though. They all enjoy each other, beyond just tolerating.

As a child when we took a stray in our resident cat never did anything but tolerate the new cat. No interest in being friends at all, for their entire "relationship", though the new cat tried her best to win her over.

 

I adopted Abby when she was 10 weeks old, at which time Muffs was 4 months old. It took 3 months before I could put them together for 5 or 10 minutes at a time with me there to supervise constantly, 4 months before I could leave both out together all the time, provided I was home to run interference...and about 5 months before I felt comfortable leaving them alone when I was at work or sleeping. So much for kittens being easy to introduce!

The problem was Muffs. She's a very timid cat, scared of her own shadow at times, and she was terrified of Abby. On the plus side, they get along extremely well nowadays (3 years later).

 

Agreed that it depends. Our litter of 5, as they got older, did not get along (mainly the female with the majority of the males). A new stray came in and the female doesn't mind him at all; the lone male left from the litter is terrified of him and it took almost 5 months for them to be in the same room together. They are still not friends, but manage to be around each other.
I laugh since it seems the new stray is the police-cat to the male/female litter mates.

 

Like everyone says it depends on the cats involved And the situation. My first cat Sophie was adopted from a rescue at 3 months old. Two weeks later we adopted her cage mate Anna from the rescue who was a month older. They were bffs at the rescue so no Intros needed. They remembered each other and have been bonded tightly since. I brought home Sasha 6 months later. She is 6.5 now was an ex queen and ex show cat who never seen a non ragdoll cat before. My other two are dsh so she was terrified and the fact that her life changes after 6 years. Took her awhile to get comfortable. Anna hated her from the get go. She is possessive dominant and territorial. She eventually tolerated Sasha but still swats her occasionally. Sasha and Sophie love each other and Sasha still hates my dog.

 

2 weeks when I adopted my adult female. And about a month when I adopted my kitten. However, the kitten didn't make it very easy to love him, he liked to bite

 

We only had to suffer one relatively brief session of screeching and hissing when Coda and Cal first met. Coda had been an only cat for almost two years, so I wasn't sure how she'd react, but after the initial first fuss, they more or less ignored each other the very next day. They're still not exactly bestfwends4evar! but Cal will let Coda groom him, and they both sleep in bed with us. The only time there's any animosity is if Coda goes after Cal's food. Food is very srs bsbs for Cal.

 

After just a week now, my one year old Cornish Rex Joan is still trying to emphasize her "ownership" of our new 3 month old Cornish Rex kitten. It's been fun to witness, outside of the occasional wince. I would have never guessed Joan's wrestling skills to be so advanced. Regardless, the little girl gives chase whenever possible.

Game on.

I look forward to when these two can relax together, which hints at being very soon!

 

I let mine work it out under supervision. However when I got them it was holidays so I was home with them almost 24/7 for those first days. and only one of my first two cats was a hisser. other one was pretty easy going and not pestering the hisser so it was fairly easy.

If they were more aggressive and I had to leave home for several hours I would probably try to separate them at least in the beginning.

 

it depends on the cat.
When I brought home my first two cats it took them about a week. They were still kittens though.

Year after I brought third cat and both resident cats didn't mind her at all, but she was terrified of them and I ended up giving her to my mom who had only one cat at that time and much bigger apartment than mine, so she (the cat) got her own room. It took her three months to be comfortable in the same room with other cats.

Strangely enough, after years at my mom's place she became super friendly and when my mom brings home new animal (she fostered few dogs and cats over the last few years) she is the first one to come and greet and never ever has any problem with accepting new animal. Week ago my mom adopted a kitten that somebody dumped and they both (new kitten and her) run and play together like crazy and she is like 8 or 9 years old cat

my mom other cat is quite opposite - with the new cat at home she spends two/three days up on the kitchen cabinets before she makes first contact with new addition, and then it takes few weeks before she is comfortable.

 

Unless it turns into a potential fight, I tend to be fairly laid back - no doubt the after effects of having lots of wild animals needing rehabilitating when I was a kid.

 

We let them scream and hiss at each other for a few minutes, then we shut Coda off in our bedroom for the rest of the night.

The next afternoon, we just opened the door and after they sniffed around one another for a few minutes, they went on with their day as if nothing was different.