All of the cats we’ve had, we had them as kittens. We just lost one of our 3, a 15 year old male, due to heart failure. That just left us with 2 gals, one 7 y.o. and one 14 y.o. who is showing some early blood work indicative of kidney problems. With the thought that our older one might not be with us that much longer, we didn’t want the one left to be all alone. So we adopted a rescue, assumed to be about 7 years old to try to match ages. Both of us are mid 70s and we want to make sure we’re here for these little gals so we didn’t want them any younger this time. The 7 year old we have is a rescue but she was a kitten. The new 7 y.o. kitty is an adult. She is extremely affectionate with people, almost comically so, head rubbing so hard she slides on the floor and almost falls over, grabbing people’s hands when they try to take them away. She is also very unflappable with anything going on in the house. However, it’s been 4+ weeks now and she has not the slightest interest in the other two cats, despite our older one wanting to touch noses with her on several occasions (doesn’t always go well). Anyway, what I wanted to know is what kinds of experiences others had, time wise, with introducing a new adult cat into an established household. Maybe she just hasn’t had enough time?
We got Ella as a kitten because our two older cats were lying around doing nothing, and we hoped that a kitten would stir them up. It worked well, as they both took an active interest in making sure Ella wasn't allowed to feel comfortable anywhere. They ran her out of every bed she tried to lie down in. No one was harmed but there was a lot of hissing going on. After a few months, I was sitting in my office and Ella came running into the office and slid under a dresser. I figured one of the older (20s) cats were chasing her, and I was right, except that it was Cutie, and she was playing with her. They slapped at each other from under the dresser for a while and, from then on, Cutie and Ella got along very well. Cutie's sister, Lydia, never warmed up to Ella but then, she didn't like her sister all that much either. Lydia died at 24, and Cutie died a few months short of 29, so that left Ella alone. Thinking along the same lines, we got Bubba as a kitten, so that Ella would have feline company. We didn't know, because my mother never explained that stuff to me, that Bubba was a boy. We thought he was a girl, but we were soon proven wrong on that front. It's been a couple of years now and Ella still pretty much hates Bubba. I think they might be playing once in a while, but Ella throws in a bunch of hisses to keep us from knowing that she's playing with that other cat. When I get something in a big cardboard box, I'll sometimes cut small holes in the box, or other holes with a flap, and they'll slap at each other, with one in the box, and the other not. As long as she doesn't have to face him, Ella is content to play anonymously. Mostly, she hisses at him, and demands a lot of alone time in the library, which we set up so that only Ella can access it. Bubba, on the other hand, has grown to be about twice Ella's size but he's still intimidated by her, and Ella is the only one who has drawn blood during a fight. Bubba ends up with scratches on his nose from time to time. He doesn't seem to have the slightest idea that Ella is mad at him, however. He seems to think she's playing. Consequently, he aggravates her a lot. To answer your question, I can't really answer your question because I have never introduced an adult cat as a part of the family. An orange cat came into my yard one day who was tame enough to let me pick her up. I carried that cat into the house to show my wife, although she clearly belonged to someone so I wasn't going to adopt her. Ella was absolutely furious that I had carried this other cat into the house.
So many people I’ve met think cats have no personalities (dead give away they’ve never been up close and personal with cats). Every cat we’ve had, we have had to figure out from scratch. It’s almost like nothing from the previous ones applies to the latest ones, just have to watch, learn and try to figure it all out. Whatever else they might be, they are undoubtedly one of the biggest joys in our lives.