When your cat grooms himself, tiny hook-like structures on the tongue catch loose and dead hair, which is then swallowed by your cat. Some of the hair stays in the stomach, which forms the hairball. Ultimately, your cat will vomit the hairball to get rid of it. Hairballs are most likely to appear in long haired cat breeds. As cats grow older, they become groomers and more proficient at removing fur from their coats. It can be disturbing to watch your cat eliminate a hairball.