Molluscivore

A molluscivore is a carnivorous animal that specialises in feeding on molluscs such as gastropods, bivalves, brachiopods and cephalopods. Known molluscivores include numerous predatory (and often cannibalistic) molluscs, (e.g. octopuses, murexes, decollate snails and oyster drills), arthropods such as crabs and firefly larvae, and vertebrates such as fish, birds and mammals. Molluscivory is performed in a variety of ways with some animals highly adapted to this method of feeding. A similar behaviour, durophagy, describes the feeding of animals that consume hard-shelled or exoskeleton bearing organisms, such as corals, shelled molluscs, or crabs.

Molluscivory can be performed in several ways:

Whales: Sperm whales, pilot whales, Cuvier's beaked whale, Risso's dolphin and species in the genera Mesoplodon, and Hyperoodon and the superfamily Physeteroidea are classified as molluscivores, eating mainly squid.

Pinnipeds: Elephant seals, Ross seals and South American fur seals are classed as molluscivores. The walrus eats benthic bivalve molluscs, especially clams, for which it forages by grazing along the sea bottom, searching and identifying prey with its sensitive vibrissae. The walrus sucks the meat out by sealing its powerful lips to the organism and withdrawing its piston-like tongue rapidly into its mouth, creating a vacuum. The walrus palate is uniquely vaulted, enabling effective suction.

Several species of pufferfish and loaches are molluscivores. As many molluscs are protected by a shell, the feeding techniques applied amongst molluscivore fish are highly specialized and usually divided into two groups: "crushers" and "slurpers." Pufferfish tend to be crushers and will use their beak-like teeth to break the shell in order to gain access to the meat inside. Loaches are specialized slurpers, and will make use of their characteristically shaped snout in order to grab hold of, then suck out the animal living inside the shell.

The black carp (Mylopharyngodon piceus) commonly feeds by crushing large molluscs with pharyngeal teeth, extracting soft tissue, and spitting out shell fragments. Four-year-old juveniles are capable of consuming approximately 1–2 kg of molluscs per day. This bottom-dwelling molluscivore was purposely imported into the United States in the early 1970s for use as a food fish and also as a biological control agent for snails—an intermediate host for a trematode parasite in fish reared on fish farms. Two snail-eating cichlids, Trematocranus placodon and Maravichromis anaphyrmis, have been tried as biological control agents of schistosomes in fish ponds in Africa. Redear sunfish (Lepomis micropholus) and bluegill (Lepomis macrochirus) have been used to control quagga mussels (Dreissena bugensis) in the lower Colorado River in the US.

The common name of some fish reflects their molluscivorous feeding, for example, the "snail-crusher hap" (Trematocranus placodon), ""red rock sheller" (Haplochromis sp.), "Rusinga oral sheller" (Haplochromis sp.) and "rainbow sheller" (Haplochromis sp.). The redear sunfish is also known as the "shellcracker".

Gray's monitor (or "butaan") is well known for its diet, which consists primarily of ripe fruit; however, several prey items are also consumed, including snails. Monitors are generally carnivorous animals, which makes the Gray's monitor somewhat of an exception amongst the varanid family.