A radula is an anatomical structure found in shellfish and other molluscs to gather algae and other food particles. The structure is tongue-like in appearance and possesses rows of minute teeth which it uses as tools to gather nutrients from its surroundings.
The radula consists of a single membrane or a split membrane depending on the species, either of which are covered in multiple rows of teeth with specialized morphology according to the environment and diet required for the species. The radula can be adapted to a number of harvesting techniques, from using the teeth for boring holes into the shells of other animals for consumption, or for grazing on algae and other minute plant life. The teeth on the membrane are called denticles, and are constantly shed and regrown as the animal damages or loses them from constantly scraping them down on their meals. These teeth are the primary method of identification for scientists.
Apart from the bivalve type of molluscs, all other known types from snails to more exotic species possess a radula. In nature, the radula can function either as a rake to scoop food into the mouth, or as a means to latch onto a plant or other food source for direct feeding. The radula is the shellfish's only means of consuming food, and plays a pivotal role in the survival of the animal.