Indoor cats got outside, now having aggression issues

Hello all!

I have 2 Oriental cats, a girl and a boy. I've had them since they were kittens and they are from the same litter. They are a year and a half old and have always been best buddies - until now!

They are indoor cats. Yesterday a window was left open by mistake and they got outside. This was probably for 15 minutes until I realised. I found Freddie (the boy) in our back garden and Ripley in next door's garden. Both kitties were very scared.

Since I brought them inside, they haven't gotten along at all. Freddie is the aggressor and Ripley the 'victim'. There is loads of growling and hissing - all night and no better this morning.

I think this is fear-induced aggression and I have read the FAQ but I'm not sure what to do! Will it pass or should I separate them? I am away from the house all day at work so I'm not sure whether to separate them during that time (I haven't today).

I tried putting vanilla on them but that didn't make any difference. Would Feliway help?

Any help appreciated. I want them to be best friends again!!! Thanks

Hello there I am assuming both have been 'fixed' so that cant be the cause of the problem.

Letting cats out doesnt normally cause this reaction - maybe there was another kitty in the area that has sparked this behaviour

It is very difficult when you are out and cannot monitor what they are up to. Has the aggression got really nasty - can you describe their body language a bit more - sorry about more questions just trying to get a picture

Hi mooficat - yes they have both been fixed.

They are not 'fighting' but are avoiding each other. When they come into contact there is hissing. Ripley is the one who runs away. Ripley sits in the furthest corner of my bedroom and Freddie sits just outside the doorway - looking in at her.

Last night they did eat dinner next to each other but the aggression flared up again later. So it's not 'full on' aggression but I am worried it will get worse if I don't do the right things now.

There are loads of mogs next door who regularly use our garden so I would not be surprised if they came into contact with one while they were outside.

Well at least there no major battles going on so thats a positive

I wonder if one is now trying to be the 'top-cat' in your house and this behavior has been triggered by contact with other kits when they were out and about - just a thought

As there are no major fights going on, I would think you are safe to leave them in contact with each other, but allowing get-away places so Ripley can have some peace when she needs it Is it possible to let them have more run of the house ?

It is a worry when your kits dont seem to be friends anymore, but of course, they are growing up and its all part of cat hierachy.

I am sure they will settle their difference - keep us posted !

Ok thanks, I guess I just assumed they would always have a perfect relationship!

They do have the run of the house, that corner of my room is Ripley's 'safe spot' I think.

I will see how they are getting on when I get home tonight.

I know you said you tried vanilla... but maybe one of them (Ripley, I'm thinking) had a close encounter with such a strong Alien Scent that the other just can't handle it. Maybe if you gave them both a bath, and then applied vanilla...?

Yes, Feliway can help a lot, especially in the form of a "Comfort Zone" diffuser. But before you invest, I'd give the bath a try...

Thanks CarolPetunia! When we got home tonight they were both in the window as normal, and both came to the door.

There is no hissing now, but they are wary. They ate together and had their usual play on the cat tree - lots of batting at each other but no hissing! Which is great.

I don't know whether they are ready to be closed in together for the night yet. Usually they are closed in downstairs while we are upstairs - otherwise we would never get any sleep. They tend to sleep entangled together in a pouch on the cat tree (the whole thing then leans at an alarming 45 degree angle) but they might not be ready for that yet.

Should I separate them overnight (one upstairs, one down) or just close them in downstairs as normal? Thanks all for your advice!

Well Freddie and Ripley went to sleep no problems last night - I think one was in the pouch and the other on a cushion. I'm sure they will get back to sleeping together soon.

What a relief!