Dwarf hamster behaviour

Question
My 11yr old daughter has 2 female dwarf hamsters living together in a large multi-storey cage in her bedroom.Recently they have started "play-fighting" a lot and squeeking/squeeling at each other.They've had a role reversal of dominant hamster.no injuries.should we worry?

Answer
Most people say that there is no such thing as play fighting in adult hamsters.  I would generally concur because I feel eventually it will lead to something more dangerous perhaps while everyone is sleeping.  If at all possible I would separate them JUST to be sure.