Why Is My Cat Leaving Dark Gritty Stuff On Pillows. Hyperthyroidism, seborrhea and diabetes mellitus can cause a cat to have oily fur. The black debris is often the bowel movement of the flea.
If you see what looks like dirt falling off onto the paper, take a drop of water and smear the dirt. However, it can also be a signal to other cats that they want to play or a signal to you that they’re scared, sick or stressed. Internal bleeding in cats can have several causes, including: