Today's Cat Behavior Quiz: What Would You Do?

The two most common reasons I've seen for this happening is a) redirected aggression and b) one of the cats coming back from the vet or groomers and not smelling like himself. If the situation doesn't correct itself in a couple of days, or if the cats are really dangerous to each other, they need to be separated and reintroduced like new cats - no matter how long they've been together, related, etc. They need to be in different rooms, smells traded via towels and toys, etc., given treats when behaving in the presence of one another, everything you would do when introducing a new feline family member. Medication would be a last resort. And all of this on the condition that both cats got a clean bill of health from the vet.

But this owner! I have no idea if she would be willing to go through all this, although honestly the reintroduction process does not sound like that much work to me. (And just because she says there have been no cats wandering outside the house or strange creatures freaking out the cats, it does not mean they weren't there. Cats see lots of things humans don't.) Frankly, I feel kind of bad for these cats that they're stuck with this person. Or are they? I'll be interested in finding out the resolution!

It sounds as if this woman is just looking for a reason to get rid of her cats. She obvioulsy wants a quick fix rather than work at a real solution, and I'm wondering at her meaning of "relentlessly".
Has the hissing and spitting problem been going on for just the past few weeks or has it been a few months.
It may be as simple as a game of dominance, and as soon as the cats figure out who "Top Cat" is they'll settle down.
I would advise the woman to just be patient and wait it out. If she's not willing to do so, then yes, she needs to re-home them, but certainly not euthanize them.

Just ran that by my husband while I was thinking it through. He said the cats are possibly fighting over who should put the woman down and who should get the privilege. He also said that if this were done, mostly everybody would be happy, including the cats and even the woman, because she wouldn't have to put up with it anymore.

My two cents worth: Vicki Halls had a case like this and it turned out to be what Janiss said: redirected aggression. This could be the sighting of other cats through the window or something else. We have a cat who often gets belted by two room mates because she is prone to urninary tract infections and wees on the bedding. I can well understand this! One of these cats may have a health issue and 'smell different' or be sore somewhere, or sensitive and is acting defensively.
Obviously it could be any number of reasons, a sore tooth, a strange smell, furniture been moved around, strange noises, ad infinitum. It doesn't sound like the owner has much sensitivity and her powers of observation may be nil as well.
Hopefully you will solve this mystery for us all!

I have a neutered boy and a spayed girl of at least 8 yrs each who share quarters with me. She arrived most recently about 7 months ago. He stalks and runs up on her to play, which she reacts to with spitting & hissing. Since he has never tried to really attack her (it always occurs in my presence because he's possessive of me: his ears are always up and forward; he never growls or vocalizes at her), I put a bell on his collar which has nullified his ability to pull "sneak attacks." I am willing to bet that in the case above 1) one cat or the other has not seen a vet in a while and may have some uncomfortable condition: although arthritis would be unusual in a 4-yr-old cat, it can happen, along urinary issues, hidden abscesses, dental issues, etc., 2) owner has not spent enough time daily playing with either or both indoor cats, 3) area shared may be too small and needs improvement, possibly vertical enhancement with a cat tree or equivalent, and each cat should have their own litter box and feeding area. Unless owner is willing to take the most obvious first steps to determine if there is a physical cause in the cat or the environment, these cats are doomed.

Perhaps one of the cats hurt the other one when they were playing. I would make sure they each had somewhere where they could go to be alone. I would also encourage the owner to take them both in for a vet visit just to make sure that no one was injured or ill.

Other then that time will probably resolve the issue.

I bet that there's another cat- outside- in their area, and that the tension of having a new "rival" they can't get at is bothering them. Also, the owner may have done something minor like, I don't know, moving a dressing-table or something, that is A BIG DEAL! to the cats ("OUR LANDMARKS ARE MOVING WHAT DOES IT MEAN?!") My cats always get a bit annoyed when I moved furniture, and investigate the changes with what I call "the Sherlock Holmes expression" on their little faces- TEH mysTERY mUsT be SoLVD!

Honestly, though, someone who would nuke the cats just for hissing needs to get help- and doesn't need to be a cat owner. Maybe she has some friends who would take them? I make friends not just with the people I know, but with their pets, and would be upset if something happened to one of the animals- perhaps she has a friend like that, who would be wiling to take them?

I mean, really... FOR HISSING? Eh, if I killed people for being loud and annoying, I wouldn't have any HUMAN family left, much less cats... :S What a lame reason.