One of my two cats (who are sisters from the same litter) has become hostile towards her sis all of a sudden. They normally cuddle up together and groom each other.

My brother (who lives round the corner from me) has a wee runt of a male cat. He's very smoochy and friendly, and he'll wander over to my place on a regular basis. Kisha has always been slightly hostile towards him, but now hisses almost every time he comes over, often accompanied with a swift swipe of the paw.

Kisha then spraying all over the house. There is a neighbourhood tomcat who hangs around, who will come right up to her and sniff around. He's been known to bail her up. I always shoo him when I see him. I wish I could put a 'T' on the end of 'shoo'... he's a little @$$.

I figured my brother's cat and the nasty Tom were to blame for her behaviour. But this is where I'm stumped...

(Her sister) Chloe was run over a week ago and has a broken pelvis. She's on 6 weeks cage rest. On coming home from the vet the following day (Kisha had been pining and meowing all night after Chloe's absence), I put Chloe in the cage, and brought Kisha to see her. Kisha growled, hissed and ran off. Since then, she's done nothing but snarl and hiss whenever she sees Chloe - she wants nothing to do with her.

I'm not sure what to do. I don't want the hostility to be permanent, because they had such a close bond beforehand. I'm hoping it's just because Chloe is caged. Any ideas would be appreciated. I've been told Feliway may help? Kisha is still spraying too, she even sprayed ME for the first time today... ugh.

As for her and the tomcat, sounds they're doing what cats do. Marking territory and sniffing. It's not the cats' faults.

Are your two cats fixed? (For that matter, is the tom? If not, that's irresponsible of them. Blame the owner, not the cat.)

As for Chloe, I wouldn't be a bit surprised if it's just all the smells and junk from being at the vet's. It's not unusual for my one cat to hiss and act funny after the other comes home from the vet, even for just a yearly exam -- and she can be that way for days, but it always goes away.

Both my girls are fixed, my brothers cat is also fixed, but the Tom isn't. It has a collar, so obviously belongs to someone despite it roaming all over the place.

I've just gone some Feliway, so I'm hoping after a few days I see a difference.

Oh, I forgot to comment on the Feliway. I just got some recently myself, due to a cat peeing in the other cat's hangout spots with me, which is mostly the bed and one chair. So I've been spraying those areas. She's been hanging out in those areas more, so I guess it has to be doing something. She hasn't peed those places either, but sometimes she would not do it for a while -- I hope it's permanent this time.

My vet's the one who recommended it and said he's seen about 50% success rate with the peeing issue. Other calming issues I don't know about, but I do believe it's doing something and that my cat likes it. So hopefully it'll calm yours down as well.