Why has one of my cats (both sisters) started bullying the other?

Are they both healthy? If not, perhaps one has picked up on the other’s illness and has started to bully. That sometimes happens with felines. Or, if the dynamics in your home has changed in any way environmentally or socially, the bully one may be acting out her stress on the more passive one.

I would rule out health issues first for either.

Rejiggering the dominance hierarchy?

maybe you should give them equal lunch money.

Both fit and healthy I am glad to report. The ‘bully’ always is quite honestly scared of her own shadow. You could be in the same room as her, in her sight, sneeze and she would run and hide. She rarely goes out for long. Her sister, whilst not aggressive in any way, is certainly more adventurous and ‘the hunter’ out of the 2. Nothing has changed over the past few weeks (apart from Christmas deccies going up) but she has seen all that before. I will keep a check and if it continue in the same vein, will take her to the vets and get her checked out. Thanks for your answer.

Because cats are inherently prepositioned toward evil.

@chocstar: Maybe the bully is getting more nervous with age, and feels the need to be “offensive” to preempt the “defensive” if nothing else is wrong with her. Vet trip is always a good idea, and maybe your vet can suggest better reasons for the behavior too.

have they been speyed? if not, this will help quieten them both down, make them more content. It seems your ‘bully cat has become discontent, and is maybe taking it out on her more successful sister, whom she feels quite safe with in doing so :)

Think I might have the answer now to my own question. Got up this morning and there is a really pungent smell outside the back door of cats’ pee. (Not one of mine). Seems like a new cat has moved into the neighbourhood (I am assuming its male). Looks like he is marking his territory and scaring my poor little cats. They are gorgeous but wimpy. Have cleaned and bleached it down but will need to keep a check on that. Any advice on how to deter it, would be greatly appreciated. Thanks all!