What would make two generally friendly cats start attacking each other?

Question

I'm not a "cat person" by any means, so forgive me if this is a stupid question!

I've got two cats (Brother and sister) who are generally quite good pals. But today, they've started attacking each other. Like, full on catwars. They circle around each other and pounce and stratch and all sorts of rather scary stuff. I know that cats sometimes play rough, but it doesn't look like playing to me. They're really going at it.

So, is this just a fluke thing that they'll get over or are they trying to mate, or what?

They've both been fixed for a few years now.

Wow. Crazy amount of answers. Thanks everyone! I'll put this up to vote, because I honestly can't pick a best answer. You were all wonderfully informative!

Answer 1

It is possible that something traumatic happened and this is re-directed aggression. Something as simple as seeing a cat outside or hearing a loud noise can cause this.

Try separating the cats for a week or two. Shortly after separation bathe them (separately). If you can't give them bathes, use shampoo wipes. This will get rid of some of the adrenaline and stress odor they have after fighting. Then, give each a towel or sweatshirt to lie on, then swap the items every day or so. This will let them each cuddle with the other's scent.

When you let them together again, immediately give them some sardines, catnip, chicken - anything that's going to make them amazingly happy. Sharing a wonderful treat creates a positive association.

Depending on how they act, you may need to continue to separate them for a few weeks and only allow them together for brief periods while you supervise them, or things may just go back to normal.

Answer 2

It would seem to me there's the chance the boy cat is after the girl cat, but I've lived in situations with both male and female sibling cats and non-sibling cats where there generally isn't a problem in the house. The female cats I've lived with have all been spayed, though.

One of them may not feel well, or maybe they're just kind of irking each other right now. Maybe give them the chance to be off somewhere by themselves for a while and let them eat separately; and they may cool down. Since they've been ok in the past it isn't as if they need to get to know each other. They more need to know the other isn't going to be bothering them for now.

I've had cats that get along so well its amazing. Non-relatives will lsit together and snuggle. A male cat would back up from the food to let the girl eat, etc. At the same time, I've recently had two female cats. One didn't do anything, while the other would once in a while want to go investigate the head or tail of the "passive" one, and then there would be a quick hissing/hitting situation for a minute.

I'm guessing with the boy and girl this may not be a one-time thing, but it may also not turn into a regular and non-stop thing either. Just separate them. Any time animals are frazzled by something or someone they feel better if they can go off and be alone for a while.

The other thing is if you calmy tell them no and do what it takes to separate them (without, of course, harming either of them) the aggressive one may learn not to do that, and the least aggressive one will learn that you will protect it. My girl cat (who just died) would wait until I stood at the edge of the "path" she wanted to walk from the door to the kitchen because she knew that meant the younger cat wouldn't harrass her as she walked by (and had to turn her back on the younger cat).

Answer 3

This is fun for them and also a dominance question. They are not trying to mate unless 1) they are not neutered 2) the female is in heat. You can tell she is in heat because she will howl and act odd and the fights are different followed by a frantic minute or two of actual mating. (Please get them fixed as this would not be good genetically for sibs to mate and there are too many kitties in the world). As they get older they will play rougher especially if the male is not "fixed" . But they will play very very rough and "go at it" and have cat wars.

Check the environment. Have you changed feeding or litter arrangements?

Have they moved into 6 months or older and hormones kicking up?

Has a strange animal or dog or cat bothered them or taunted from outside the window or did a squirrel get them "het up"? If so they might take out that energy on each other

Is one sick?

Have you changed anything? New baby in the home? New animal? New guy or gal or roomate or guest?

Have you MOVED the food or litter?

Has there been stress in the home? That can set them off.

Have you recently moved or changed furniture?

Look at all the factors. But it may just be really dominence. And if you've not fixed them, do it please it will calm them and you really don't want kitty incest. :-)

If you find a source of stress work on it or let it pass. Look for signs of mating (not just sitting on top and biting on the neck, that last longer than mating and it is a part of dominence--mating will include the neck hold but also have the mating for 30 seconds and end in a howl and hissing. Look for changes or source of excitement for them.

Answer 4

Cats are felines and are naturally inclined, or better worded, instinctively prone to be territorial and aggressive towards other felines. Being that they are from the same mother doesn't change the course natural instilled in them, including the mating act! If the cats were spayed recently, it will probably take quite afew months, up to a year, for them to become less hostile or aggressive in their tendencies. Just let nature take it's course with these and you really shouldn't be alarmed at what sort of display you may observe!

Answer 5

Cats are the same as people, they think, too. If one pissed the other one off, they're going to fight. One cat may have done something the other cat doesnt like, like ate some of their food, or layed in their spot, or rubber their scent over the other cat's scent. It sound territorial to me because neither of them can now differentiate between the other of what sex they are since they have both been fixed.
I had a few cats and all of the ones who werent fixed attacked my cats that were, but since that isnt the case for you, Im definate its a Territorial issue. Say hi to the tigers for me!

Answer 6

I have quite a few cats, five to be exact, three of them are siblings. I have discovered that when a strange cat comes into the neighborhood and my cats see them this usually sparks some sort of primal thing in them and they start fighting each other. It's like this strange cat in the 'hood has brought out the tiger in them and since they can't get to the strange cat they strike out at each other.

I know that cats are very scent oriented when it comes to their pack or pride as they are called in cat lingo. And I think when a strange cat comes it must cause the release of some sort of homones or something to change their individual scents especially to each other.

I found that if I take a towel and rub each cat and go to another cat and rub them with the same towel until I've rubbed all the cats with this towel several times it will end the issues they have and peace comes to the household because they all smell alike. I used this same trick when one of my cats kept picking on one of my dogs. I rubbed the dog with a towel, then the cat. This made the dog smell like family to the cat. At least I think this was why she left him alone after that.

Hope this helps!

Answer 7

I own two cats as well and I know what you mean. Allot of it has to do with territory and who's the favorite. I suggest you split them up. If ones eating put the other outdoors. After awhile it will pass. They could just be playing rough with each other too. If they are trying to mate I think you should have them fixed.

Answer 8

Ahhh, the lovely adolescent stage. It is fun to watch but they have no concept of time. They play in bursts until they are worn out and then sleep for a few hours only to get up and play again. We are fostering one who is about 7 weeks now. Every night I put him in a separate room and say "night night". He climbs up into his bed and we find him there every morning. Of course, he is only 1 not 2. We have a mama kitty with 4 kittens who are 1 1/2 weeks. After the mom leaves we will be keeping her kittens to socialize until they are old enough to be adopted out. I can't imaging what 4 kittens will be like. I doubt 'night night' will work. The only suggestion I have is keeping them in a separate room, maybe an office or bathroom (with the lid down!) with a box to sleep in. Don't forget water in case they get thirsty. Good luck and just remember, "this too shall pass". And saying 10 past two, at night is fine. The period between sunset and sunrise is considered night. Either would be correct but neither is wrong.

Answer 9

Some times something as simple as a smell or plant can set things like this off temporialy (like cat nip,... yes some cats get violent and aggressive).

There may be some Jealousy (yes, animals have emotions for those that think they are wind up toys).

There may be a fight over who has domonence (I can't spell, sorry). There usually is an order and levels to things,... you are likely the highest but they may be fighting for who is higher then whom.

Some times animals outside start things, other cats in the neighborhood (strays) could be invadeing their terroritory (in their minds and senses) and they are wondering if they are bringing them in, one of the strangers, or takeing too much terroritory with these new additions squeezeing in (you may never know those cats outside are there).

One or both may be ill (something as simple as too much ear wax in one ear can cause confusion or disorientation some times).

This will hopefully pass in a couple days, or a couple weeks.

If the Male is Mounting the female then he is trying to gain the higher position OR yes... he may be trying to mate with her... because she has injuries or health issues makeing her smell like blood or other cats nearby are triggering this. For "Big Cats" in the wild (Lions, Tigers,.. ) this isn't a common problem because they have a range of senses that tell them how closely they are related,.. ones kept in captivity are inbred and this fades or forced to be in a small enclosure while in and heat and the worse happens,... in Domestic Cats there has been way too much inbreding,.. they have LOST alot of things the "Big Cats" are able to do.. Breeders even FORCE THEM to INBRED for desired effects,.. so your cats wouldn't have anything detoring this.

Answer 10

Something that can occur in cats who have been previously friendly and compatible is called "redirected aggression". Could they have possibly seen a cat outside who distressed them?

Get a bottle of Rescue Remedy from a health foods store and treat both cats by shaking the bottle well and putting three or four drops on the fur between their ears. Do it as many times a day as you can while they are in this "intense" state. It will help them to calm down.