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Homicidal cat? Answered

We have two cats at my house and i don't know what happened but the smaller cat has been trying relentlessly to "kill" the other.

The attacked cat has been acting odd a little before the incident, and wherever the smaller one can smell the other he starts growling.

They have been living together for half a year without problem. We have no idea whats wrong but any help is appreciated.


Female cats, after being spayed, can act aggressively towards other pets and people post surgery. The cause could be a reaction to anesthesia, or there could be a formation of adhesions that is causing miserable discomfort and the undesirable behaviour. Even though the procedure is routine, it is invasive surgery that can have complications, and with pets, they are unable to tell you if something is wrong.

You should really take the cat back to the vet that performed the surgery and discuss the post surgical aggressions, and have her looked at. The vet should be able to figure out if there is something going on that could be causing pain and this behaviour. The vet should also have recommendations (or perhaps a prescription) that would help in this situation.

Scar tissue is something that can form after a surgery. (It happens in humans too). And it can cause problems, by affecting muscles, nerves or even other organs. It can also be very painful. If that's what happening to your cat, then it would explain why she is so miserable and behaving the way she is. But, the only way you are going to know for sure, and the only way you can really help her is to take her back to the vet.

Hormones can also cause "weird" behaviour, particularly if the cat was older when she was spayed.

(Most vets are pretty good about post surgical visits, and may not even charge a fee for a follow up. Especially when you have concerns).

:) After a year, I would hope so...

(but for monsterlego, I think he needs to bring his cat back to the vet. A friend of mine lost his cat due to internal bleeding from being spayed. It doesn't happen often, but it can, and since animals can't tell you what's wrong with them, you can only go by their behaviour and overall demeanor).

Sadly we've made the decision to give the aggressive cat away, nothing has worked and its been two weeks. :(

I have one particularly aggressive cat she is super duper fat and sheds year round I still have her but she will not go near any of the other cats

P.S. are your cats from the same litter?

No, we had two older cats one had died so we got a new one (the aggressor)

Thats normal all of my cats are from different litters and they cannot stand being near each other

One other thing, the attacker cat only acts weird around the other cat.

Did the cat that's being attacked recently go somewhere unfamiliar, like the vet? Some cats are very sensitive to smells that they don't recognize.

I have a friend this happened to. They actually had to give the cat a bath (oh dear) and keep them separated for some time.

It could also be a territorial problem - are the cats fixed?

I let the attacked one outside before it happened. I do think it has to do with the scent of the cat.

Interesting, the attacker was fixed about a week before this happened. (oh yeah they are both female)

My Cats are like that they love each other for the first year and if your lucky maybe two. but it's a natural instinct going back to when cats were wild animals I. . recommend giving them each a cardboard box to sleep in

Trust me I'm a doctor

(who has 3 cats)

I'm talking insane cat issues here, the attacker is completely demonic near the other, its painful to watch. :P

My cats are like that it goes back to wild big cats they are very territorial it is also common to see this happen between females (all three of my cats are females)

Yeah the attacker will do the, the other one's scared out of its mind.

My cats both were spayed last year and although they don't attack each other
they still hate being near one another

Its been almost two weeks now, what was the longest fight you've seen?

Sadly we've made the decision to give the aggressive cat away, nothing has worked and its been two weeks. :( (we still have a week left with her though)

Oh no! I'm sorry to hear that.

Will she be the only cat in the household? That might be better for her. :)

I highly recommend Jackson Galaxy, cat behaviorist, for solving problems like this. He has a website, facebook page, a book, and the TV show "My Caat Fom Hell". A couple of the shows have even dealt with two cats that have horrible constant fights. Some from the beginning and some after a couple years of getting along.

Please google his name & show. I think you can even watch the TV episodes online through the Animal Planet website. He's relly good at explaining cat behavior.

I have two cats that have gone from daily hellacious screaming fights to one fight/week from following his advice. In our case, I had to make sure that the smaller cat had a safe place to retreat from everyone when she needed quiet time AND I made a point of waving the bird-on-a-string toy around while we were watching TV every day. This allowed them to use their hunting instincts on the toy instead of treating each other like prey.

Sadly we've made the decision to give the aggressive cat away, nothing has worked and its been two weeks. :( (we still have a week left with her though)

Sometimes that is the only answer, for the health and sanity of all involved. It sounds like you have responsibly re-homed her, which is entirely different from dumping her.

I had to re-home a couple of roosters that didn't work out with our hens about 10-15 years ago. As long as you are finding a good home that is a better fit, everyone will be happier.

We haven't done anything yet, but yes my mom has been driven mad by them.

Oh yeah, for the toy thing - a toy that they can grab and bite like real prey is better for them than a dot of light. The laser pointers are very frustrating for the cat.

You're not alone monsterlego!

Evidently, this behavior is not uncommon.  If at all possible, keep the Cats separated until they calm down and aren't a danger to each other.

Here's an informative link for you:

Cats suddenly hate each other!

Good luck!!!!

Sadly we've made the decision to give the aggressive cat away, nothing has worked and its been two weeks. :( (we still have a week left with her though)

For separating the cats, you might have to resort to an indoor screen door. They can see and smell each other, but not hurt each other. This way they get re-acquainted without endangering each other. You can give each of them snacks while they are close but separated to make being near each other a positive experience.

I put one on my study doorway. It actually has a cat door cut into it and is more for keeping one pesky human away from the cat, but if I needed to, I could cover the kitty door.

We stuck the aggressor in a cat carrier and put him near the other, nothing big happened yet.

Another possible issue - Is there someone in the house who plays rough with one of the cats? We have a household member who would routinely "pull the pin on the cat grenade" .

Holly liked a little rough-housing, but it was always too much, and always lead to the cats attacking each other instead of the person who stirred things up. Now that I have locked the screen door (with cat door) on my study, she has a place of refuge when she needs it, even when I am at work. and both cats are calmer.