When a cat has a fur ball they go off and be by themself. Then they start making a honking noise; which scares the living daylights out of you if you don't know what it is! In the beginning, I thought that they were choking on something. Then my daughter told me that it was a hair ball. Sometimes they'll throw the hairball up with what ever they have eaten, and other times they'll just swallow it. Brushing your cat and giving them dry food that has a special hairball preventative formula in call help a lot.