How do mollusks use a radula to obtain food?

The radula is a specialized, ribbonlike organ found in the mouths of most mollusks, with the notable exception of bivalves. It is supported by a cartilage-like structure called the odontophore and is covered in rows of small, hardened teeth known as denticles.12

To obtain food, mollusks use muscles to protrude the radula from the mouth and spread it over the odontophore. The organ functions primarily through a rasping motion, where the denticles scrape food particles from surfaces or drill into the shells of prey. As the radula is withdrawn into the mouth, it carries the collected food and debris into the esophagus.21

The structure of the radula is highly adaptable; its teeth vary significantly in shape and number depending on the species' diet. For instance, some predatory species have evolved specialized teeth that act like harpoons to inject poison into prey, while others use them to cut through vegetation. Because the teeth wear down during use, the mollusk continuously produces new rows of denticles at the rear of the radula to replace those lost at the front.21