Thoughts on sudden kitty aggression?

I mentioned this in the Photos thread, but -

Itty-bitty has recently become extremely aggressive towards Tiny. She’s about double his size. She was raised with him, so it’s not like he is a ‘new’ cat. But about 2-3 weeks ago, she suddenly started chasing him through the house - not playing either, but seriously. To the point that he makes a mad dash for the cupboard over the washing machine first thing in the morning and won’t come down until she is in her crate at night. I’m getting worried about his water intake and potential UTIs.

I caught her at it today. She chased him behind the couch and they had a mad tussle - before I could get there, he broke free and ran like hell down the hall and back in his cupboard. She meant business.

I made a vet appointment to get her checked out. Maybe get her some Prozac. But I can’t let her keep doing this to Tiny. The fact that it was so sudden has me worried.

You might also get the victim checked out… there could be an illness or something that makes him seem/smell/otherwise different which is why he’s suddenly getting attacked.


Is it possible that she saw/smelled/heard something outside that triggered an episode of redirected aggression? It can sometimes take them a couple weeks to get over that. Feline hyperesthesia can also cause aggression, but you probably would have seen some additional signs by now.


I thought about that too, but aside from being chased, he seems fine.

I hope you can get it figured out soon. I have one who is the outsider in the group and sometimes they will all gang up on her and pick on her in a mean way. One of my bullies was recently spayed. I hope she settles soon or its back to the vet.

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I don’t think so - she doesn’t really spend a lot of time looking out the windows. And none of the outside cats have been upset by anything.

I haven’t seen any other signs of the hyperthesia, but she has been looking at my shoes lately like she thinks they’ll attack her.

Is her coordination ok? No walking into stuff or reacting/staring at any other objects?

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Yes, check poor Tiny. Poor guy - who needs that?

My other cats seem to know when one is weak or sick - lately it’s Bonnie. They have all decided to go after her especially the two other girls. I can’t control what they do when I am not there but when I am, I march loudly thru the middle of the quarrel and either pick up Bonnie or the aggressor and take them somewhere else in the house. Throwing a pill bottle or dropping a loud pan also helps. That way they can break up without losing “face.” If anyone gets too ugly, they get shut in the bathroom. Duncan was an absolute fiend and would really go after the other cats in a manner guaranteed to draw blood or make injuries. On Prozac he went. Settled his happy ass right down.


Have you tried Feliway or something stronger like Ovaban?


Her coordination seems fine. I haven’t tried Feliway yet - I was thinking about trying it. Does it actually work?

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I will try to get Tiny looked at, too - the problem is getting him in the crate!

I’m thinking she may need the Prozac. She’s always been odd, but this is beyond that.

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Feliway was useless for my girl, though I’ve heard from others who’ve had good experiences. Ovaban did work as a general, low dose anxiety/OCD medication - the shot worked better than the pill. Ovaban is like synthetic pregnancy hormones.

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A low dose of gabapentin might also help mellow her.

My cat went on clomipramine for a while, which also helped tremendously, but it takes a much longer time to see the effect.

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Cats pick on ‘the weakest link’ = injury or illness related - glad you’re taking Tiny for exam - Jingles !


Sorry didn’t think about Feliway - probably because I am allergic to the stuff. But I have heard others say it worked and some say it did not. When I had the stuff in my house, I really could not see any difference at all in the behavior.

@Alex_and_Bodie_s_Mom - prozac is great. It gave me my Duncan back instead of the angry aggressive pissing idiot I had.


This is true so it is best to rule out any physical problems.

Cats also pick on “the weakest link” = personality/attitude related. If Tiny is mild mannered and afraid of confrontation, Itty Bitty may be trying to climb the ladder of cat hierarchy and politics.

It could also be that Itty Bitty, although she’s spayed can still feel some effects of a heat. My Ella is spayed but she acts more aggressive and less patient during the times of the year she would be in heat if she wasn’t spayed. I think this is fairly common in spayed females.

Here the Kittens With Mittens consider the finished basement their territory. Rotten Ralph is the alpha and rarely goes downstairs. When he does the boys will attempt to gang up and push Ralph’s buttons. It doesn’t last for long because Ralph knocks their heads together and then they leave him alone. Yet when they are all on the main or 2nd floor they show him the utmost respect.

Cat politics are funny.


I have wondered about the false heat - she does have them, despite being spayed at 5 months. Is there anything to do about that, I wonder?

Tiny is also the quietest and most docile of the cats, so he’s an easy target. But it was just so sudden. She grew up with him.


Didn’t your vet say that there was something about her that didn’t look like a domestic cat?


Yes, he did … that is always in the back of my mind… but she’s full grown now and only about 10lbs, so how not domestic could she be?!

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I don’t know. I really know nothing about cats, I remembered that you mentioned it. Half domestic?