Dear Most Esteemed and Knowledgeable Kitties:
I have two female indoor cats. They escaped one night, and when they came back the next morning, something had changed. Now one of the cats is hissing at the other. Why is that?
~ Brenda
Siouxsie: We actually got two letters on this subject in just the last few days, so it seems like this is a pretty important topic to address.
Thomas: We think something scared both of the cats while they were outside. Perhaps one of them responded to the fright in a way that frightened the other cat and provoked aggression. Now they’re in a pattern of overreaction to each other.
Kissy: Another possibility is that one of the cats got into something that made her smell different. It’s like when you come back from the vet and you smell different from the other cats, and then they hiss at you because you smell strange, and it’s not like you can help it because your person kidnapped you and … *sniffle*
Siouxsie: Stop your sniveling! We’ve got work to do here!
Thomas: Oh, Siouxsie, be nice.
Kissy: As I was saying, before I was so rudely interrupted … this phenomenon of redirected aggression after a frightening experience is pretty common among cats.
Siouxsie: *hisss* Don’t make me come over there!
Thomas: Stop it, both of you! Anyway, redirected aggression can provoke reactions as dramatic as full-on cat fights that draw blood.
Kissy: The good news is that your cats are clearly on the very low-reaction end of the scale — for now.
Siouxsie: Which means that now is the time to help your kitties get to know each other again and re-learn the joys of hanging out peacefully together.
Thomas: First of all, it’s very important that you understand your cats’ aggression-related body language. This will help you to understand which cat is inciting the aggression and which one is being bullied.
Kissy: The earlier you notice the signs of imminent aggression, the earlier you can step in with a distraction that will help your cats redirect their energy more appropriately. The best distraction tool for cats that aren’t actively fighting or hissing is an interactive toy.
Siouxsie: By using a toy like a feather wand or other type of “thing on a string” in order to take the cats’ attention off each other, you’ll give them a way to work off that aggressive energy without cussing at each other.

Two ginger-colored cats wrestling by Wikipedia user Benyon3, distributed under a CC-BY-SA-3.0 license
Thomas: If you don’t have a toy handy, you can distract your cats by clapping your hands together and saying something like “Hey!” in a firm but not screaming tone.
Kissy: Mama does that when we get into hissing matches or when she sees that Thomas is staring at me with that special “I’m about to kick your tail” glare.
Siouxsie: And it usually works, as long as she notices before the confrontation goes beyond hissing to chasing and crying.
Thomas: Well, Kissy, if you wouldn’t freak out every time I get near you, I wouldn’t start chasing you! Jeez!
Kissy: It’s not my fault! I had a hard life on the streets … just a tiny little cat with a bum leg, pregnant with five kittens, barely able to provide for myself …
Siouxsie: What’s that I hear? Is it the world’s tiniest violin playing just for you … or is it the distant warble of a waaaaambulance?
Thomas: Be nice, Siouxsie!
Kissy: Yeah! Be nice!
Siouxsie: I’m telling you — don’t make me come over there! …
Thomas: Oh, hi, Auntie Margot! Do you have some noms for us?
Kissy: Noms! Noms!
Siouxsie: What are you feeding us tonight? Can I test taste it?
Thomas: Anyway, Brenda — the best thing you can do to keep the situation from escalating is to try to stay calm yourself. Your cats will pick up on your emotional energy and if you stress out about their behavior, their aggression may increase. Instead, be alert and be ready to distract the cats with something more fun than stare-downs and hissing.
Kissy: If you don’t have a toy handy, clap your hands and bark “Hey!” That’ll distract them from staring at each other without harming your relationship with them. Good luck, and please let us know how things turn out!
Siouxsie, Thomas and Kissy: Om nom nom nom! Om nom nom! Nom nom nom …
I have two males cats they are close to 3years old. It’s almost one and a half a year they had a big huge fight, all of a sudden and cos I tried to save the cat which was attacked, and I was attacked. They both are seperated and I really wish to see Candy and Roxy together. I wish you guys would help.. I wish I could find some magic portion…
Hi, Ruby. This is a tough one. Your cats have gotten used to being terrified of and angry at one another. We suggest that you do a reintroduction, using Feliway (a happy-cat pheromone) and a VERY gradual program of desensitization and positive reinforcement. Here’s a column we wrote about the process of reintroducing cats: https://www.paws-and-effect.com/my-cats-are-attacking-each-other-help/
This situation is pretty hardcore, since the problem has been burned into their brains for a year and a half, but it is solvable. An episode of the TV show “My Cat From Hell” last season featured two cats who’d been in a horrifically aggressive relationship for years, to the point where one of the cats was essentially imprisoned in the back room of the house.
We’d also recommend that you talk with your vet and ask his or her advice on how to handle the situation. See if your vet knows a cat behaviorist in your area. If not, go to the International Association of Animal Behavior Consultants, http://iaabc.org/, and find a certified behaviorist in your area. This is a case where it really would help to get a professional involved.
Thank You for all your articles, I really enjoy them and the advise is very helpful with my two cats. I have two female cats myself, Sami is 2 and Magi is 1. Sami was a outside ferel, found at 5 weeks, and I adopted Magi from a shelter at 5 months. They do well together, although have their moments. Last year Sami got out, was gone for 2 months, when she came back, Magi wanted nothing to do with her. Magi hissed and growled at Sami for a long time, and boy did they fight! I thought I would have to get rid of one, but with time and interference between fights, they learned to love one another again. Yes cats do not like out of routine experiences!
Hi, Tammy. We’re delighted to hear that your Sami and Magi were able to become friends again. Sometimes all it takes is (a lot of) time and patience. Purrs!
Brenda, if you happen to be reading this, buy some Feliway diffusers too. Those are full of kitty-safe feel-good chemicals that promote relaxation and less fear. Or you can buy some Rescue Remedy and smear it on their heads. Again, this promotes a lessening of tension.
Good luck with your girls. I hope it works out.
My kittehs got to ignoring the clap and “Hey!” maneuver when peace negotiations were not going well, so I resorted to stomping toward them. Literally, stomp your feet and walk toward them. That would break things up pretty quick!
Regarding the potential that someone has a smell on them, you could try kitty wet wipes if not a bath, and/or get their smells on each other (rub a washcloth all over one, then rub it on the other, and vice versa).
I also had better luck with feliway collars than diffusers, but that’s just my experience!
Ooh, I hadn’t tried the rescue remedy rubbed onto their head… now there’s a new idea!
Ok khaos and edward are inside cats, have been since 2012, and they are fixed males! They get along awesome, never had a problem, till now, just last week, khaos was hissing, growling and howling at edward, this lasted about an hour! Fastforward to last nite, and same thing! Hissing, growling and howling!! We did separate them, now 7 hours later, and khaos is still hissing at Edward!! Wat could of happened???