A limpet is a snail relative that has evolved to live in aquatic environments. Limpets can be found in both fresh and salt water all over the world and they come in an array of shapes and sizes. Taxonomically, the term “limpet” is somewhat poorly defined. Most people use it generically to refer to mollusks with distinctive conical shells and it does not describe a specific taxonomic grouping, such as a class or order of mollusks.
Generally speaking, limpets are gastropod mollusks. They have a single, very muscular foot that they use for locomotion, and conical shells that may be smooth or ridged. In some species, known as keyhole limpets, there is a small opening at the apex of the cone. These organisms eat by scraping material, such as algae, off the rocks they travel over with a barbed tongue known as a radula. They have a pair of sensitive antennae to help them navigate the underwater environment.
Although these aquatic creatures do not have eyes, they have other adaptations and features that allow them to interact with the world around them. Special chemoreceptor cells are highly sensitive to certain chemicals found in the mucus that limpets leave behind them. Limpets can follow their own mucus trails to navigate back to preferred sleeping and eating spots. Like other animals sensitive to chemical signals, it is believed that these animals can also communicate with each other with chemical messages.
One large clade of mollusks is known as the Patellogastropoda or “true limpets.” Organisms outside of this clade may also be referred to as limpets, though not necessarily universally. The inconsistency in terminology reflects the clash between the common names used by members of the lay public to describe organisms that look similar and the scientific names based on taxonomic classification of organisms. People who want to avoid confusion may use the full scientific name of an organism in question.
The expression “clinging like a limpet” is a reflection of the strength of the foot of a limpet. Like several other mollusks, limpets are capable of clamping down tightly on a rock, making it virtually impossible to remove them without damaging them. Limpets are eaten by humans and other animals and in some regions, the limpet is considered a delicacy. Recipes for preparation vary, but generally, cooktimes are rather short, as overcooking may result in the limpet developing a rubbery texture.