one of our cats (had them about 8yrs now) has started to attack the other one..

It may be worth having her checked out by the vet to rule out any medical condition that is making her more aggressive. Otherwise it could be that something has happened outside the house to upset her - a new cat in the neighbourhood or something similar. This happened with one of my cats some years ago, although it didn't make him aggressive just very nervy. The vet prescribed a short course of antidepressants (I felt bad that even the cat needed medication to survive in our family ) We also used a 'feliway' diffuser (is that advertising?) which emits natural pheromones which help to relieve stress.

I've had quite a few cats over the years but have never heard of this problem. I would do some research over the net and/or ask my vet.

Good luck!

thanks all...yes I have heard of the "feliway" diffuser, the trouble is we have open plan house and I think I read it covers so many sq metrs.so would prob need 2 or 3 of them, the cats have never really got on very well..although they are from the same littler (so I was led to believe) and yes there are new cats in the neighbourhood...lady n daughter got a kitten and before long the neighbouring Tom had its wicked way and she produced 4 or 5 kittens only one male amonst them, we are led to believe the kittens have not been "seen to" spayed etc and are now coming up to about 5/6 months old!! they have started visiting our garden so maybe that is the poblem.thanks for sujestions

My sister has this problem when she introduced a new, rescue, cat into her family of cats. One especially dominant female took exception to the newcomer. The vet suggested she bought a powerful water pistol and zap the fighting cats. She did this and after a few days the fighting stopped. The old female never fully accepted th younger one but limited her aggression to snarls and spitting.

Two years ago I got two cats from the Cats' Protection League. They were mother and son. At first the son was the dominant one and the mother, who was really sweet, disappeared for ten days. I was really upset as I felt she had been driven away. To my delight she returned with a load of 'attitude'. The son hung around for a week then he disappeared as well. We now know he is living on a neighbouring farm and being looked after so we will leave well alone. Funny things, cats.

Agree absolutely merlot very strange animals cats, that's why I have dogs.

I had this problem. It got so bad that I had to find a new home for the aggressor. She would lie in wait for the shy one and sometimes draw blood. My house is set back from the road, but the chase would continue through the cat flap and I was worried that an accident might be caused. I unsuccessfully tried Feliway along with two weeks separation followed by gradual re-introduction as recommended in cat behaviour books bought from Amazon. I really miss my lovely Nutmeg who had previously been a calm, loving pet. Luckily she has a great new owner , a retired vet, where she is the only cat.
I hope you find a solution.

My mother cat has become senile and is clearly not long for this world (but not in pain). The other four cats are her offspring. The oldest one, a neutered male, has taken to grabbing her by the ears and shaking her and the other three quite obviously don't like her much these days. I am convinced it's because she is frail and confused that they no longer regard her as one of their pack.

biker I suggest that you get both cats checked by the vet.

When my mother cat went missing for ten days I'm sure she'd had enough of her stroppy son so went to do a recce of the surrounding area. They'd only been with me six weeks. She's a lovely cat and is devoted to us so I'm glad she wasn't the one to leave. Nimbus, her son, is now happily catching mice in a large grain store.

Just another thought biker - you say your home is open plan, and as I'm sure you know cats are very territorial. In a multi-cat household they need their own space which they can protect even from the cats who live with them. I have had up to three cats at a time and two of them loved each other dearly but on the whole I believe cats are loners and prefer to be on their own. It sounds as though your poor cat is feeling threatened and is taking it out on her sister, so she may need help to feel safer. I do agree about seeing the vet before anything else.

This just made me think - cats are indeed strange creatures, nothing like dogs. They prefer their own company, their own territory, and only like visitors on their own terms. A lot like many gransnetters. Perhaps there's a reason cats and old ladies go together

Thanks nightowl when I have thought about it.it seems to be at feeding time! that it happens most...it doesnt happen a lot but over the last 2 weeks maybe about 3 times, they both come in the kitchen to be fed but the bigger one,,sort of gauds the cuboard where the food is, almost as though she thinks the otehr one is going to steal all the food before she gets it...I think I will feed them seperate see what happens. thanks for all the advice and if it does continue or get worse then I shall pop up to the vets and havea word. all has been quiet today (so far)!