Introduced New Kitten Over a Month Ago, and the Aggressive Territorial Behavior is Just Getting Worse

by Benjamin
(Rhode Island)

We started with two cats that were sisters Malum and Nibs - no cat problems with these. When they were about 8 to 9 months old we brought our newborn daughter home from the hospital. Nibs immediately took an almost guardian role of my daughter, while Malum hissed and ran away. After about a week Malum returned to normal, and even started cuddling up to my daughter.


About a month ago we brought a new kitten, Mary, into the house. Nibs again immediately was friendly, while Malum went into an aggressive territorial mode. For the first few days she wouldn't be in the same room as Mary, if Mary was in the room where we keep the litter box and food, Malum wouldn't eat or go into the litter box until she was sure Mary wasn't in the room.

After a few days she started to get better about being in the same room as her, however if Mary tried to get close to her, Malum would hiss at her, we dismissed this as normal behavior that would pass given time. Malum would still be sociable to us, hopping into our laps, nuzzling us, sopping up as much attention as she could.

However as time has gone on she just seems to be getting worse. She hides all the time, if she comes out of hiding and anyone tries to pet her she just hisses and tries to swipe at us. We started letting her into our bedroom, without allowing Mary in in hopes that giving Malum a safe haven would allow her to come to terms with the new kitten. At first this seemed to work, when she was in the room she was incredibly sociable, she would follow us around the room, she would curl up with us when we went to bed.

Again however as time went on this changed, still without letting Mary in the bedroom Malum now has become completely antisocial, she swipes at us when we try to pet her wherever she is, and she recently within the past week and a half has taken to peeing on any random article of clothing, or backpack, that is left on the floor, even in the living room and kitchen. We have a mat in the kitchen, where the litter box is which is cleaned daily, that has had to be washed 3 or 4 times over the past week because malum pees on it. Can you help us? We love Malum with all our hearts but nothing we do seems to help at all, just makes it worse.


Reply from Liz (Editor): I'm sorry to hear you're having these cat problems - I will see what advice I can offer.

Malum is obviously a lot more uncomfortable than Nibs with change. She's had to adapt to your baby, which it sounds like she's done quite well, but now the new kitten has come along it's upset her again, and from what you've said she's taking it pretty badly this time.

I think it would be worth having a conversation with your vet; from what you've said, it does sound like Malum is very upset and the vet may suggest some sedative / tranquilizer tablets for her as a short term measure. This may relax her enough to get her through the worst of it and should help to stop the inappropriate peeing, swiping etc. You could also try a Feliway diffuser or Bach Flower Rescue Remedy, both of which can have a calming effect on cats.

I don't know how the kitten was introduced to the cats, but I think a good idea would be to almost "start again" and re-introduce them. I'd suggest putting the kitten into a separate room for a week or so, and then following the advice on this page:

Our Cats are Fighting

While the kitten is in the separate room, you can encourage Malum to become more sociable again. I wouldn't force her to come out of hiding, I'd just let her come out when she's ready. When she does, call her over but again let her come to you in her own time - i.e. don't try to force it until she's ready. When she does come over, give her loads of fuss, praise and attention.

Hopefully, if the cats are re-introduced to each other and Malum has a bit more time, and possibly a little help from medication short term (if your vet thinks this is appropriate) things should be OK again. It may take Malum many months before she realy accepts Mary, but if you persevere you shold get to a situation where they can live together OK, even if they never become the best of friends.

Thank you for your question and best of luck.

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