Help!!! Sudden aggression among cats who never fight

Help. I hope someone can help. I have three cats, mom Essie age 4, and her daughters, Stinkerbelle and Mukluk age 3 (all are spayed). I have had them for about 3 and a half years and they have never fought (except in play). In fact earlier today I took a nap and two of them were snuggled up on the bed with me. They are usually very friendly toward each other. I left the house around 5:00 pm. My boyfriend was out of the house but returned at about 9:45 pm or so. We are often gone so this was nothing new. When my boyfriend returned he noticed that Stinkerbelle was in the corner (where she had pooped- she had also pooped somewhere else in the house- I think she may have been sick because she and the other cats always use the litter box). He then noticed Essie "stalking" Stinkerbelle, growling with a gutteral tone. Essie then attacked Stinkerbelle. He said they fought and he had a hard time getting them apart. He was alarmed at how aggresssive they were. He then put Essie in the bathroom. I got home about 10:00 pm. Boyfriend had already called the vet (spoke to a tech as it was after hours and person was not sure what might be going on). The tech was not sure what to make of it. She wondered if there had been any changes lately. There have been no relevant changes that I am aware of. We were on vacation until a week ago, but the cats stayed home with a sitter and no problems were reported. We had no problems with them for the past week. When I got home, I checked Essie and Stinkerbelle both and did not notice any injuries (at least not obvious ones). After about half an hour, I carried Essie out into the living room and as soon as she saw Mukluk she tried to attack her and then Stinky. After I got Essie back into the bathroom, I called the vet tech (who boyfriend had talked to earlier). She was not sure what the reason for the aggression was. She thought my idea to keep them separated overnight was a good idea. Meanwhile all the cats were being affectionate toward me and seemed OK. Because the behavior just seemed so strange and Essie seemed like she was OK. After about an hour (or more)I carried Essie out and was holding her in the living room. I let go of her briefly and she seemed OK. The Stinkerbelle who was in the kitchen started growling at her and before I could stop it she chased after Stinkerbelle and Mukluk two. Obviously that was a big mistake. After we got Essie back in the bathroom. Stinkerbelle and Mukluk were in separate rooms one with each of us and they were both upset and growling. All three are now separated for the night and probably longer. I have no idea why they are behaving this way. Anyone ever heard of anything like this before? Other than the aggression, they all seem to be OK (though I realize that that does not mean they are OK). I am keeping Stinkerbelle and Mukluk apart to be on the safe side- earlier in the evening, they hissed at each other a little but did not attack each other. I am planning to take at least Essie (the aggressive one) to the vet on Monday. Any advice or ideas? I am completely baffled. Normally they get along so well and are very friendly with each other. Any advice would be greatly appreciated.

Stinkerbelle needs a vet. When a cat is injured or ill their scent changes. The other cats no longer recognize the scent and therefore treat the alien scent as a strange cat and attack.It is a common problem, and even though you can't *see* the injury or illness, the other cats are telling you it's there. Keep them apart until the one cat can see a vet. The pooping out of the litter pan is another way cats try and get our attention when they are ill.

Also, the number one reason for illness in cats is stress. Changing routines, you leaving- even though you believe they are used to it, they may not be. They like everything the same, and we adapt to changes much more easily than they do. Please take your cat to the vet on Monday.

Thanks for the response. An update. Everyone seemed fine during the night. In fact Stinkerbelle was extra affectionatate purring and rubbing up against me when I was out in the living room/kitchen where she spent the night-maybe because she is not used to being alone. I have not noticed any more litter box issues since last night. This morning, Stinkerbelle was meowing non-stop outside of the room Essie is in. I put Essie in a cat crate and then opened the door. Stinkerbelle eventually walked up to the crate and walked around it sniffing at it. Essie seemed neutral. I did not hear any growling. Then I sent Stinkerbelle back outside. I then put Stinkerbelle in another crate in the living room and carried Mukluk over just so she could see that Stinkerbelle was in the crate (Mukluk has been very cautious and timid since this all started and I wanted her to know that the other cat was contained). Mukluk hissed at Stinkerbelle and went back to the bedroom (where she had spent the night). I think poor Mukluk has just been terrorized by the whole thing. Whatever made Essie so aggressive yesterday toward Stinkerbelle also seemed to influence her aggression toward Mukluk too. So far Stinkerbelle seems to be OK but I will plan to take her to the vet tomorrow. Any ideas on what I should do today? So far Essie and Stinkerbelle have been fine (when Essie is in the cage) but I don't want anymore fighting.

11:30 am (eastern time) Sunday Update. Essie and Stinkerbelle appear to be civil to each other (so far with Essie in the crate). I don't want to risk any fighting. Is it OK for Stinkerbelle to (visit) in Essies room (when Essie is in the crate?). I also tried to see how Mukluk and Stinkerbelle would be toward eachother. I put Stinkerbelle in a crate again and when Mukluk saw her she hissed. Then Stinkerbelle hissed back. Then Mukluk hissed back. End of experiment. Any ideas on helping Mukluk and Stinkerbelle re-establish their formally friendly (playful but friendly) relationship? Stinkerbelle appears to be fine (suppose she should still go to the vet tomorrow though).

Just some thoughts- if you are letting stinkerbelle outside your home, it is kitty season and she could have gotten into a fight. Or, she could have found a lovely scent to roll in, changing her scents as well. There are a lot of possibilities as to why this has happened, or is happening. It is best to rule out a health issue first, especially in light of the fact that you seem to travel a lot. Cats can get into a state while their owners are absent, and really anything can happen. I am not saying your cat is ill- but that she might be. I know with my crew- I have 9 when one of them becomes the attacked, there is usually an illness or injury that has triggered the others. Again, ruling out a health issue should be first. Cat's don't like to show they are ill. Because if they do, they know they move quickly from being predator to being prey.

I am no expert but I think MA might be right...Its Stinkerbelle who has pooped and is the one the others are treating strangely..So, take her in first instead of Essie.
The problems seem to be stemming with the one being attacked or hissed at..

Again, I don't have any experience with this (other than with dogs) but I hope all turns out ok. Keep us updated after the vet visit!

Thank you for your replies. These cats don't go outside with the exception that I live in an apartment and they sometimes get to go out on the balcony. There are other cats that they can see from out second story apartment but none that they would get into direct contact with. Usually they just see a neighbor cat who is 50 + feet away. So it doesn't seem like rolling in something is the issue- though I guess it could not be completely ruled out either. This has surely been a very strange (also scary and unpleasant) experience so far. If a cat has some weird smell, how long might this last? Would feliway be a good idea (of course not in lieu of the vet), but thought it might help things calm down. If so, is Feliway available at pet stores or only mail order?
Thanks again everyone.

1:35 pm eastern time. Latest update. Essie was in her crate in the living rooom and I carried Mukluk over from the bedroom and put her by the cage to see what would happen. Essie hissed and growled at her Mukluk hissed and ran off. Anyone know what to make of this? I completely regret having done what I did with those two as it seemed to traumatize them both- but I naively thought that they would be OK with each other.

I think everyone pretty much said the best thing you can do which is to take Stinkerbelle to the vet.

Feliway is a popularly suggested aide in many problems that cats have. I would try it if I were you. You can buy it at Pet Supplies Plus if there is one near you. Call around to some pet stores around you and ask, not all of them carry it.

I have Stinkerbelle scheduled to go to the vet tomorrow morning. I am also going to bring Essie just to see if there is anything the matter with her. I will also see if I can find the Feliway spray. I am also going to get the books that were recommended Psycho Kitty and Twisted Whiskers by Pam Johnson Bennett. Thanks for all of the advice- hope it is not to difficult to resolve the problem.

It's good that you're taking them to the vet. This happened with Milo and Spyder last year and I took Milo straight to the vet. Turned out he had a high fever and had to be on antibiotics for a week.

Update: Everyone went to the vet today. All cats deemed healthy. The vet felt that the culprit for the aggression was probably smelling other cats outside (I guess it is mating season?) I just installed a Feliway diffuser in the living room (cost 33.29 at the vets- is this a good price?). Eveyone is being somewhat more civil, although Mukluk is still hissing at her Momma and Sis (Stinkerbelle) every so often and therefore only limited visits. Essie and Stinkerbelle seemed to be getting along fine until about 3 minutes ago when they started hissing and growling so I immediately put them in separate rooms. I will continue to keep them separate (unless under supervison) for the next few days. I will also rotate their placements (e.g. which cat is residing in Bedroom 1, 2 or livingroom/kitchen) until things have settled down. Any input would be most welcome. Thank you, Cyndy

Update 5/17/05. Yesterday, under supervision, my cats all had some good behavior with eachother. Essie and Stinkerbelle were even sleeping on the same chair for awhile. However, there were also some episodes of growling and hissing that I responded to by separating the cats. Well when my boyfriend came home from work, I told him that things seemed to be going better, some hissing and growling but no attacking. I said, it seems like now we can tell when they are getting upset and avoid fights. Unfortunately, it turns out, I spoke to soon. I can't remember which cat was in the kitchen first, Essie or Stinkerbelle, but one walked in and when Essie noticed that Stinkerbelle was there, she went ballistic and attacked her. I quickly picked up Stinkerbelle and both cats were yowling (like screaming bloody murder). I walked toward the hallway and Essie attacked my leg (drawing blood). We were able to chase Essie into the bedroom and close the door. I noticed then that Stinkerbelle had pooped while I was holding her. So... What I think happened in the first place (my initial post in this thread) is that Essie went ballistic and attacked Stinkerbelle and the reason that Stinkerbelle pooped outside the litterbox was because she was terrified (rather than sick). It turns out that there are quite a few feral cats that hang out in my neighbors yard (backs onto a rural area). My neighbor thinks there may be as many as 5 adult cats and there are a few kittens too. I had not heard them mating at night because I wear earplugs (but my boyfriend says they often are making quite a racket). Our kitchen and one of the bedrooms face the neighbors property and I would imagine that what ever my cats are smelling must be stronger there. So, Feliway has not yet solved the problem. When possible, I will try to keep windows and screen door closed. I am also going to see if there is a spay and release program in my area. If these feral cats could be spayed and released, it might solve the problem. The strange thing is that I think we must have had the same "mating feral cats" issue last summer we did not have any problems with aggression until last weekend.

It's unfortunate you could not find someway to trap those stray cats and get them fixed and re-release them. I would bet if you invested in a black light and shined it outside your home at midnight you would see urine spayed all over the outside walls. An unfortunate side effect of unneutered males and unspayed females marking territory, and quite possibly what is driving your cats bonkers indoors.

Update of Tuesday 9:00 pm. Everyone spent the day in separate quarters. Mukluk is still hissing at Stinkerbelle (I think Mukluk is scared). I haven't attempted to see how Essie and Stinkerbelle are with each other yet. I contacted a neuter and release program in my area (for the strays) and am waiting to hear back from them. I feel this would be the best solution (neuter/release of strays) if it can be done. I have the feliway diffuser in the living room/kitchen area and am using the spray in the bedrooms. I am also switching my cats between rooms every 24 hours so that everyone smells everyone else. I hope things can get back to normal... it is so much nicer when everyone is getting along.

Wednesday pm. this evening, everyone got along, no hissing or growling. I hope this will continue. I will still keep them apart (unless under supervision) until I feel like they are over their hissy fits. I also went to the doctor today for cat bite treatment. I got a tetanus shot, a shot of antibiotic, and some oral antibiotics. I guess you can't be too careful with animal bites. Well I hope that Essie, Mukluk, and Stinkerbelle will continue to be nice to each other. I also hope that I am able to get the neighborhood strays neutered and released.

How has this turned out. I noticed your post was from a few months ago. Our cats started this behavior yesterday. It started when there was another cat outside on my deck. One of my cats is hurt and we're taking them to the Vet tommorrow.

Surprised that someone posted on this thread after all this time. Fortunately, things settled down and everyone has been pals for several months now. I was using feliway regularly but since things were going so much better discontinued it. Will probably plan to use it again when I am on vacation and in the summer months. Unfortunately I never heard back from the neuter and release program. I'll try again though. Hope that your cats settle down- I remember how traumatic it was to have my three going at it. So glad they stopped.

Try rubbing them individually with towels and then using the towels on the other cats, so they all end up smelling the same. I know one of mine gets confused by just seeing a strange cat outside through the window sometimes and then attacking another inside cat, but it doesn't last long if I just let them chill in separate rooms for half an hour. I wonder if things are not being prolonged by having kept them separate, in carriers, all this time? Sometimes they just need to work it out, awful as it may seem to us, but if one becomes the victim of the other two at once, that's obviously not a good thing. Have you tried catnip for all in the same room, same time, followed by a special treat at fairly close quarters?

Not sure if you were refering to me specifically, but after we talk to the vet today, we may see if the younger, injured one will stand up for himself. We bought the Feliway and plugged it in. So far they can't stand each other.