Random aggression

[toddypu]

I have two cats, one 3 and the other 2. I got the 2 year old when he was a kitten, and aside from the adjustment period, they've gotten along well. They lick each other, play with each other, eat and sleep in my bed together, and stay in my bedroom together while I'm at work. They're both fixed and up to date on their shots. Today I took the 3 year old outside to groom her, which she loves. I used a damp rag to wipe off the excess hair from the brushing. When I brought her back inside, however, my little guy attacked her! It's so random! It's been about 8 hours and they're still hissing and howling at each other!

It's so bizarre! I don't know why he is acting so aggressively towards her, and as the eldest, she's not backing down. I've kept them separated since, and even cuddled my boy until he calmed. He's really cuddly and loves to be pet. But when I tried introducing them when he was calm, he still hissed and howled at her. Mind you, he's a punk who's afraid of his own shadow. I've never heard him hiss or seen him attack anyone. My big girl is usually the mean one.

Right now, since he's the aggressor, I have him in the living room and her in the bedroom. I even tried putting vanilla extract on their necks, tails, and chin to no avail.

Help! I don't know what to do! I plan on trying to introduce them through the living room door tomorrow, but I hate to see our little family in disarray. What should I do?

 

[toddypu]

He still tries to attack her when he sees her. He even hissed at me! He's never hissed at me before! He's fixed, doesn't seem to be in pain, and I just don't know what to do!!!

HELP!!!!

 

[basschick]

you say you took the three year old outside and used a damp rag on her.  if she picked up new smells outside, from any grooming product or from the rag, that could upset the other cat.  heck, maybe he just didn't like the idea of her being out of the house and then inside again - cats aren't big on change.  or since he's also hissing at you, maybe you have a different smell.  but maybe he has a UTI, which does make some cats aggressive, among other behavior changes.  if this doesn't calm down, a trip to the vet may be in order.