A corallivore is an animal that feeds on coral. Corallivores are an important group of reef organism because they can influence coral abundance, distribution, and community structure. Corallivores feed on coral using a variety of unique adaptations and strategies. Animals known to be corallivores include certain mollusks, annelids, fish, crustaceans, flatworms and echinoderms. The first recorded evidence of corallivory was presented by Charles Darwin in 1842 during his voyage on HMS Beagle in which he found coral in the stomach of two Scarus parrotfish. History While visiting the Cocos (Keeling) Islands in 1842, Charles Darwin was told by an Englishman living on the islands that there were large shoals of parrotfish that subsisted entirely on coral. Darwin dissected several parrotfish and found pieces of coral and finely ground calcareous material in their stomach. This led Darwin to correctly theorize that some species of parrotfish consume coral and contribute sediment to the environment by passing finely ground particles from coral skeletons. In 1952, the first descriptions of organisms actively consuming coral were written by Jacques Cousteau and published in National Geographic. During his trip to the Red Sea aboard RV Calypso, Cousteau swam with a pair of green humphead parrotfish and watched them take regular bites and leaving white scars on the coral around them. Like Darwin, Cousteau also noticed the sediment particles that were produced in the parrotfishs' waste and settled to the seafloor. Cousteau noted the leisurely speed with which the parrotfish consumed the coral and remarked that they appeared "unhurried" and like "sea cows, browsing on stone pastures." The term "corallivore" comes from the Latin word corallum for coral and -vora for to eat or devour. Types Approximately one-third of known corallivores are obligate corallivores, while the remaining three-fourths are facultative corallivores. Obligate corallivory is defined as having a diet which is at least 80% coral. Obligate corallivores are present in all tropical oceans, except the Caribbean. Facultative corallivores are defined as organisms that regularly consume coral without it comprising a large percentage of their diet. It is thought that some facultative corallivores, such as some damselfish, eat coral to promote algal growth. Many facultative corallivores also graze on algae, which competes with coral for space and resources. By grazing coral, it may provide better conditions for algal growth. Aggressive grazing may keep the algal community in a state of accelerated growth, effectively preventing the transition to a