I have a two year old cat that lives indoors and recently she has started nipping at misc. objects. She has always been a nipper when playing, but within the last month she has started nipping at my carpet, sheets and comforter. She also has been scratching her teeth up and down a metal pole on my fish tank stand. I wouldn't think at 2 that she would be teething, so what could be causing this and how can I correct the problem before she rips a hole in my bed linens?