New Cat Agression!?

I have posted before so some may know my story but if not, here it is.

I adopted a kitty from a shelter in October and he has finally come around to be trusting and quite the nice kitty. He is about 21 months old and from what we know, he has always been an indoor kitty and was neutered at a very young age.

Recently, a stray showed up but was the most tame cat towards people that I have ever met, so since it was freezing outside, I brought him into the garage to get him all situated. I just had him neutered/declawed this past Friday, he is 10 months old and may have always lived outside but was litter trained and loves to just lounge on carpet and couches, and since that, brought him into one of our bathrooms where he spends most of his time.

What scares me is that this new stray kitty seems to want to attack our indoor kitty and from what I see, the indoor kitty wants to play and doesn't even realize he's being stalked. Last night the new kitty managed to sneak behind the indoor kitty and I caught him. His tail was super frazzled, not moving but like super giant puffed and he was laying really flat, about 5 inches from the indoor cat which was looking the other direction. I freaked out because I felt like the new guy was about to attack mr. indoor so I started yelling which made the new kitty jump and the indoor kitty run. They hiss and growl at each other every time they see each other.

Granted, they've only formally met over the past 3 days but I am nervous this behavior will never stop as it seems quite aggressive from the new kitty.

1. After a neuter, it seems to take 6 weeks for the hormones to change, will the new kitty be less aggressive once those 6 weeks come and go ?

2. Should we continue to keep the kitties separated until the 6 weeks has passed, only allowing them in the same room while being supervised ?

3. Is there a chance that this new kitty could attack mr. indoor and then the indoor kitty will become stressed out forever ? I definitely cannot deal with that as this cat was stressed since we got him and has just recently started coming around to us. We know multiple people that would love this new kitty, so if this situation is likely, then I will let someone else adopt him...

4. Ideas on what to do with this. We haven't tried feliway or anything like that...

Thanks SO MUCH

Three days is far too short a time to tell whether or not new kitty is going to always be aggressive.

First of all, he's probably not happy and in some pain from the declaw. Pain can make cats aggressive.

Declawing cats in and of itself can make them aggressive - they no longer have their natural defense system and it can change their "psyche." Only time will tell.

Hissing and growling is normal during the introduction process. In fact, it can happen any time. After five years, there's still hissing and poofed tails from time to time in our home.

New kitty should probably be separated at least until his paws have healed.

I would definitely invest in Feliway and use it liberally around the house.

Have you done any scent swapping?

Take several rags or small towels. Rub each kitty all over. Put indoor-kitty scented towels under new kitty food dish. Put treats for new kitty out on another indoor-kitty scented towel both morning and evening.

Do the same thing for indoor kitty with new kitty scented towels or rags.

Consider temporarily putting a screen door in place of the door that closes the room off between the cats. Or, consider purchasing two baby gates, and stacking them. This way the cats can see and smell each other, but can't get at each other. It's a pain to get in and out of the room that way - which is why temporarily using a screen door is so much easier.

Any time there's positive interaction (no hissing or growling) between them through the divider, praise them both to high heaven.

When you do begin supervised introductions, bring indoor kitty into new kitty's room for a few minutes at first. But wait until interaction between the divider is not aggressive or upset in any way. Have new toys or something ready to give to each kitty during the first introduction. If it goes well, keep lengthening the amount of time indoor kitty stays in new kitty's separation room. It may take a couple of weeks or more.

Remember to praise kitties when they just sniff at each other - or anything that isn't negative. Also, keep an empty can with coins in it to rattle or clap loudly if new kitty attacks indoor kitty. The loud noise, as you found out, will startle them out of whatever's going on. However, it's best to clap or use the can rather than yell. Never pick either cat up to separate them.

The idea is to give each cat time to adjust to the other. Indoor kitty as resident cat takes precidence. Make sure you give each cat lots of attention and play time. The rest of the introduction process is to help the kitties come to associate good things with each other, and for indoor kitty to think it's a "party" any time he's around new kitty.

In addition to the Feliway, you may want to also consider purchasing Multicat Household Harmony flower essences: Http://www.catfaeries.com.

However - there are going to be instances of hissing and growling. This is normal. What you have to watch for are the other signs to determine whether new kitty is trying to play or actually attack indoor kitty. Ears back, tail down and agitated - back ridged - growling - these are all signs of actual aggression, or growling on indoor kitty's part can be warning to new kitty to keep away. Lying on the back is NOT a sign of "I give up," it is a defensive stance. Tail up, ears not back - batting on the forehead - this is play or dominance, not aggression. Poofed tails can result when a kitty feels threatened - but also happens during play.

Laurie

I would probably be angry and aggressive too if someone had just amputated my toes. Sadly this happens all too often with declawed cats, and the owner has no idea whythey are acting this way. Claws are a cats first line of defense and its just been literally ripped away from them. So some become aggressive. Some stop using the litterbox. Others become withdrawn and just don't act like the cat they used to be. Unfortunately you can't go back and give him his claws back, so you need to work extra hard to integrate him into your home. It might take a long time. I rescued a cat in Aug. of 2006 and it's only been a few months since he and my orange tabby can be in the same room together. And I didn't declaw him.