Last night she had Tabby chasing her around the house so fiercely that it was waking me up over the course of two hours. This is not normal for them. Are we having a full moon? Actually, I'm rather glad that they were doing it. As indoor cats they don't get much exercise.
I hope you enjoy the following links regarding articles about cats chasing each other and aggression. Fortunately, I have rarely had to break up an encounter to prevent cats injuring each other - click on these hyperlinks