Cats naturally keep themselves very clean and in the process of self grooming they often end up swallowing a lot of their loose and dead hair, forming tufted balls in their stomach commonly known as hairballs. Feline tongues anatomically have barb-like features that trap loose, previously shed hair. On swallowing, the hair mixes with the saliva, gets ingested and accumulates as a ball in the stomach. Most times the hairballs are harmless and easily pass through the digestive system without a problem. On other times, if not through the stool, the cat will vomit up the trapped hair.