I have had my cat since she has been a baby. I got her in August. Tonight I got a new kitten and my cat hates her. She has been hissing and growling at her since we brought her home. She is also hissing and growling at me and my 11 year old daughter whenever we come near her. How long will this last? Is there anything I can do to make this meeting go a bit more smoothly? What should I do when she hisses at the people? to get a little better idea about my old cat, see the thread about the obsessed cat...that is mine.