Odd behavior between my two cats after incident

[catforshort]

I came home today to find the wind had blown open my back door. The back door had been open for who knows how long while I was at work (at most, 11 hours). When I came home I found the two cats in my room growling at one another. They have never been like this to one another. They hang out with me together on the bed, or wherever I am. One will even groom the other. They grew up from 8 weeks of age until now at 3 and a half years old. 

Since this incident today where the back door was open for a long time, the cats are growling at one another, hissing, and being quite unfriendly. This has never happened before and I am not sure what to do or what to expect. Will this behavior go away?

 

[furmonster mom]

This sounds kinda like what happens when I take someone to the vet.  When they come back, there is all manner of hissing, growling, and swatting.  Things usually settle down after a few days.  The general theory is the strange smells on the one who went to the vet set the others off. 

It could be that the door being open let in all kinds of strange smells, or they went outside and found a strange, uncomfortable world, and now they are just outta sorts.  Cats generally don't like big changes, but they will most likely settle back down in their familiar surroundings.  It just might take some time.

 

[betsygee]

Is there a chance another animal came in while the door was open?  This happened to us.  We have three cats who love each other, but they started acting oddly and aggressively towards each other, which had never happened before in five years.  It took us a few days to figure out that a neighborhood cat had been coming in their cat door!  It was eating their food and fighting with them while we were gone.  It really shook them up.

We got a new cat door that was secure from intruders.  It then took a few weeks before our cats felt safe in their home again but they DID go back to normal and being loving to each other.  

 

[catforshort]

I have seen a neighborhood cat that hangs out outside my house, but I haven't seen it around the back where the doors are. I suppose there is a chance it could have come in during this time.

 

[catforshort]

So last night I was awoken at 3am to them screaming at one another, hissing, chasing, and fighting. I have never seen them like this. So I put one in the bathroom and dealed with his meowing all night.

 

[betsygee]

You may want to try getting a Feliway diffuser, and some calming treats for them.   They may  have been in some kind of altercation with the neighborhood cat.  Are yours normally indoor cats?

 

[catforshort]

 
You may want to try getting a Feliway diffuser, and some calming treats for them.   They may  have been in some kind of altercation with the neighborhood cat.  Are yours normally indoor cats?

They are indoor only cats and have not ventured outside before.

 

[betsygee]

I'll bet something from outside scared them. Poor kitties.  There are several products that may help--calming collars, or treats, or plugging in a Feliway diffuser.  

 

[catforshort]

 
I'll bet something from outside scared them. Poor kitties.  There are several products that may help--calming collars, or treats, or plugging in a Feliway diffuser.  

I put a calming collar on him and plugged a Feliway diffuser into the room. After a few hours I opened the door and let the one that is being aggressive out. As soon as he saw the other cat he started growling and chased him off up onto a dining room seat. I have put him back into a closed room, but this is making me stressful since I can't sleep with him meowing all night long in that room.

 

[betsygee]

It could take some time for them to return to normal.  My cats took several weeks to get back to their normal selves after we had the incident with the neighborhood cat coming in and scaring them.  

How are they today?

 

[catforshort]

No difference unfortunately. I am still having to keep them separated as one of them is very aggressive towards the other.

 

[betsygee]

This is not unusual--it could take some time.  And there could be other reasons the cats are aggressive.  Have either of your kitties had any other problems--are they both eating and using the litter box as usual?  When's the last time they had vet check ups?  Sometimes cats get aggressive when they don't feel well.

 

[catforshort]

This is not unusual--it could take some time.  And there could be other reasons the cats are aggressive.  Have either of your kitties had any other problems--are they both eating and using the litter box as usual?  When's the last time they had vet check ups?  Sometimes cats get aggressive when they don't feel well.

The one that is acting aggressive behaves completely normally whenever the other one is not around. He will purr, play, sit on my lap, all the normal stuff. Both are using the litter box as normal, eating normally, and don't show signs of sickness. It has been a while since they went to the vet, but the backdoors being open has to be the cause. He was already a sensitive cat. For example, he would growl when he would hear a diesel truck drive by the house for some strange reason. I still haven't seen any progress between the two. Maybe he needs to be put on anxiety medicine.

 

[feralvr]

Quite a scare for your cats while you were gone away at work and that door blew open. This behavior you are seeing is extremely common after such an episode as this. So just know that. It is very possible that whatever happened that day put enough of a scare into them that they experienced a huge setback in their relationship. Hard to say how many hours that door was open before you got home and thus, leaving the two hissing/growling for who knows how long. It is very possible that one of them ventured outdoors and then returned bringing the outdoors in. Really, no matter, because we will never know exactly what happened between them during that very stressful ordeal.

Can you let the aggressor out of the room and put the other kitty in that room for a night or two. Basically, sharing the space and sharing some time with you in bed at night. Taking turns. Actually, unfortunately, closing the aggressor up in a room may be making things worse since the episode. Too many changes now and his life has been turned upside down since. Still, you are doing the best you can and really, separating them at least initially is the way to go.

IMO - at this point, so that things can quickly return to calm and not let these emotions keep festering, I would opt for medication, personally. A low dose. Something to take the edge off and allow the more upset kitty to calm and realize that the danger is over and that his friend, is STILL his friend. It does take time, lots of it, depending on each individual cat and how quickly they rebound after something so scary. Again, , this is very common. Maybe a call to the vet at this point and letting them know what happened. Hopefully, your vet will just offer something via phone call so as not to stress out your cat with a vet visit. This behavior came on immediately that day and I highly doubt it is a medical issue. So the vet should be able to put something up for you. Your cat would only need this initially and temporarily until he settles.

Some helpful tips and articles: http://www.thecatsite.com/a/six-surefire-strategies-to-reduce-stress-in-cats

The behavior your cats were initially displaying is called Redirected Aggression (towards each other, or could have been one of them only) Unfortunately, sometimes, this can really put a damper on a solid indoor cat relationship and again, IMO, sometimes medication is your best bet to get things quickly back on track.
http://www.thecatsite.com/a/re-directed-aggression-in-cats

 

[BonitaBaby]

 
I put a calming collar on him and plugged a Feliway diffuser into the room. After a few hours I opened the door and let the one that is being aggressive out. As soon as he saw the other cat he started growling and chased him off up onto a dining room seat. I have put him back into a closed room, but this is making me stressful since I can't sleep with him meowing all night long in that room.

I see this thread is a few days old, but the Feliway diffuser might take up to several weeks to work, so Feliway spray for now might be better if the problem is still happening. If one went outside and then came back in and smells different to the other cat, could you possibly either ... wash them both or wipe them down and/or do scent swapping with them with the towels or something?