Glossary
Tongue papillae
The tiny backward-facing hooks on a cat's tongue that work like a comb for grooming and a rasp for stripping meat from bone.
Also called: barbed tongue, rough tongue, filiform papillae, cat tongue
A cat's tongue feels rough because the top is covered with tiny, backward-pointing spines called filiform papillae. They are made of keratin, the same material as claws and hair. Each is shaped like a small hook with a hollow tip.
The papillae make the tongue a very good grooming tool. They work like a comb, pulling out loose hair and dirt, and they help spread saliva through the coat, which is how cats cool and clean themselves. In the wild the same rasp helps scrape meat from bones, and a cat lapping from a bowl uses the tip of the tongue instead, curling it like a ladle.
The spines face backward, so hair that sticks to them tends to be swallowed. Most of it passes through the gut, but a clump sometimes comes back up as a hairball. An occasional hairball is normal. A cat that retches again and again without producing one, that stops eating or has a swollen belly needs a vet right away, because a blockage can be serious. Brushing regularly cuts the amount of hair a cat swallows.
Last reviewed November 7, 2026