My anxious kitty is upset about our new kitten

[Samthecatlady]

So I have had my first cat for 4 years, he is a flame point, cross eyed and very anxious because he was abused by my ex husband. He cut off his whiskers and threw him around and had choked him which was the final straw in which ended our marriage. But since then he has been treated very well, I will not let anyone hurt my baby. It's been 3.5 years since I kicked the ex out and my kitty is better around other people and has always been curious about other kitties. I mave moved several times and there has been another kitty in the house and he is usually very calm. We recently adopted a new kitten that was hanging around my parents house we got him a check up and he's healthy so we brought him into our home. for the first two weeks we kept them seperate and then let them eat next to each other through a door. Then we let them out and they get along fine usually they even sleep touching. Well the kitten got out this morning and we couldn't find him until this afternoon and so we were so happy that he is okay and that we could get him out of the cold but now my first cat is back to hissing at him again and being anxious. What do I do to make both kitties feel safe in the home?

 

[ArtNJ]

You are saying they were getting along well, but the kitten got outside the house due to an escape for a bit, and now there was hissing?

If so, this is a well known thing. Cats are HEAVILY scent based. Escaping and being outside for a bit can temporariy change a cats smell enough that sometimes a friend-cat may perceive them as a stranger. This is called non-recognition aggression, although thankfully it sounds like you have a mild version with mere discomfort and no actual aggression.

Provided that they appear unlikely to actually fight, you can let them work this out. You can possibly speed this up by "rescenting" the kitten with the smells on his favorite blanket (or similar item). If the kitten has no such item, I believe the learning in our guide on this is that you can also use one with the smell of the older cat. If they appear likely to fight, a short separation, and perhaps even a gradual reintroduction, might be needed.

Not all cats are equally prone to non-recognition aggression. Since you have had this issue, your older cat is likely a bit prone to the issue, and you should be cautious when you take the kitten to the vet, as that is another situation where non-recognition aggression can occur. Perhaps not every time -- you may have been to the vet without the issue -- but it could occur in the future depending on what happens at the vet and what scents adhere to the kittten. The spay/neuter procedure, being a longer procedure including surgery, is a likely spot where this could occur. You can prepare a scented towel by rubbing the kitten before the vet visit, and use it to rescent the kitten with after the vet visit before greeting the older cat. Similarly, I'd avoid the groomer entirely (or at least the shampoing there) unless truly necessary, as the shampoing (and perhaps other scents present there) can cause this issue. Dramatic haircuts dont seem to help either. There are some tips in this article:

How To Deal With Non-recognition Aggression In Cats – TheCatSite Articles

 

[Anne2021]

ArtNJ already gave you some advice on how to "rescent" things and I really don't have any additional advice. I just wanted to share that I had two cats (now living with my adult daughter) who went through this even though they had a long-term relationship. Our dilute torti, Stormy, has a feisty personality. She would growl at delivery men. Even so, she was good with welcoming new cats if it was done well. She and our other cat at the time, Leo, would both like to go outside in the flowerbed or on the patio for short times with our supervision. We always just expected when Leo had an outing that Stormy would get riled up at him when he came back inside and act like she didn't know him. The older they got, the shorter those periods of time of non-recognition got. I realize that your cats haven't had a long-term relationship yet, so it may require a bit more readjusting, but I wanted to encourage you that outdoor time for one cat can confuse the other cat (or cats) in the home.