I had a femal cat named Fred, adopted. We loved her very much. She had the weirdest habit, unfortunately . She was always indoors, threre were no fleas. She had scabs on her belly, well we could not figure out why. Turns out... she was chewing her nipples off. We have no clue why. She would only do it when we were asleep. Once we finally figured it out she died one year later. She was very well fed, just a strange girl.