A molluscivore is a
carnivorous
A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose nutrition and energy requirements are met by consumption of animal tissues (mainly mu ...
animal that specialises in feeding on
molluscs
Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...
such as
gastropods
Gastropods (), commonly known as slugs and snails, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda ().
This class comprises snails and slugs from saltwater, freshwater, and from the land. Ther ...
,
bivalves
Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed by a calcified exoskeleton consis ...
,
brachiopods
Brachiopods (), phylum Brachiopoda, are a phylum of animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, while the fron ...
and
cephalopods
A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...
. Known molluscivores include numerous predatory (and often cannibalistic) molluscs, (e.g.
octopuses
An octopus (: octopuses or octopodes) is a soft-bodied, eight-limbed Mollusca, mollusc of the order (biology), order Octopoda (, ). The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, ...
,
murex
''Murex'' is a genus of medium to large sized predatory tropical sea snails. These are carnivorous marine gastropod molluscs in the family Muricidae, commonly called "murexes" or "rock snails".Houart, R.; Gofas, S. (2010). Murex Linnaeus, 1 ...
es,
decollate snails and
oyster drills), arthropods such as
crabs
Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tailed" in Greek), which typically have a very short projecting tail-like abdomen, usually hidden entirely under the thorax. Their exoskeleton is often thickened and ha ...
and
firefly larvae, and vertebrates such as
fish
A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...
,
birds
Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...
and
mammals
A mammal () is a vertebrate animal of the class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three middle e ...
. Molluscivory is performed in a variety of ways with some animals highly adapted to this method of feeding. A similar behaviour,
durophagy
Durophagy is the eating behavior of animals that consume Seashell, hard-shelled or exoskeleton-bearing organisms, such as corals, shelled mollusks, or crabs. It is mostly used to describe fish, but is also used when describing reptiles, including ...
, describes the feeding of animals that consume
hard-shelled or
exoskeleton bearing organisms, such as
coral
Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria. They typically form compact Colony (biology), colonies of many identical individual polyp (zoology), polyps. Coral species include the important Coral ...
s, shelled molluscs, or crabs.
Description
Molluscivory can be performed in several ways:
*In some cases, the mollusc prey are simply swallowed entire, including the shell, whereupon the prey is killed through suffocation and/or exposure to digestive enzymes. Only cannibalistic
sea slugs, snail-eating cone shells of the taxon
Coninae, and some
sea anemones use this method.
*One method, used especially by vertebrate molluscivores, is to break the shell, either by exerting force on the shell until it breaks, often by biting the shell, like with
oyster crackers,
mosasaur
Mosasaurs (from Latin ''Mosa'' meaning the 'Meuse', and Ancient Greek, Greek ' meaning 'lizard') are an extinct group of large aquatic reptiles within the family Mosasauridae that lived during the Late Cretaceous. Their first fossil remains wer ...
s, and
placodont
Placodonts (" tablet teeth") are an extinct order of marine reptiles that lived during the Triassic period, becoming extinct at the end of the period. They were part of Sauropterygia, the group that includes plesiosaurs. Placodonts were generall ...
s, or hammering at the shell, e.g.
oystercatchers and
crabs
Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tailed" in Greek), which typically have a very short projecting tail-like abdomen, usually hidden entirely under the thorax. Their exoskeleton is often thickened and ha ...
, or by simply dashing the mollusc on a rock (e.g.
song thrush
The song thrush (''Turdus philomelos'') is a Thrush (bird), thrush that breeds across the West Palearctic. It has brown upper-parts and black-spotted cream or buff underparts and has four recognised subspecies. Its distinctive Birdsong, song, w ...
es,
gulls
Gulls, or colloquially seagulls, are seabirds of the subfamily Larinae. They are most closely related to terns and Skimmer (bird), skimmers, distantly related to auks, and even more distantly related to waders. Until the 21st century, most gul ...
, and
sea otter
The sea otter (''Enhydra lutris'') is a marine mammal native to the coasts of the northern and eastern Pacific Ocean, North Pacific Ocean. Adult sea otters typically weigh between , making them the heaviest members of ...
s). It is hypothesized that human archaic ancestors such as early-Pleistocene ''Homo erectus'' on Java were predominantly molluscivorous: stone tool use, pachyosteosclerotic skeleton (slow+shallow diving), much larger brains (seafoods + DHA), fossilisations amid edible mussels (''Pseudodon'', ''Elongaria''), island colonisations (e.g. Flores), early-Pleistocene intercontinental dispersal along coasts and rivers, enamel damage caused by "oral processing of marine mollusks" (Towle cs 2022 AJPA), ear exostoses (chronic cold-water irrigation), shell engravings (google "Joordens Munro"), etc., google "gondwanatalks verhaegen".
*Another method is to remove the shell from the prey. Molluscs are attached to their shell by strong muscular ligaments, making the shell's removal difficult. Molluscivorous birds, such as oystercatchers and the
Everglades snail kite, insert their elongate beak into the shell to sever these attachment ligaments, facilitating removal of the prey. The carnivorous terrestrial pulmonate snail known as the "
decollate snail" ("decollate" being a synonym for "decapitate") uses a similar method: it reaches into the opening of the prey's shell and bites through the muscles in the prey's neck, whereupon it immediately begins devouring the fleshy parts of its victim. The
walrus
The walrus (''Odobenus rosmarus'') is a large pinniped marine mammal with discontinuous distribution about the North Pole in the Arctic Ocean and subarctic seas of the Northern Hemisphere. It is the only extant species in the family Odobeni ...
sucks meat out of bivalve molluscs by sealing its powerful lips to the organism and withdrawing its piston-like tongue rapidly into its mouth, creating a vacuum.
*Another method, used by
octopus
An octopus (: octopuses or octopodes) is a soft-bodied, eight-limbed mollusc of the order Octopoda (, ). The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. Like oth ...
es,
nautilii and most molluscivoruous sea snails, is to use their
radula
The radula (; : radulae or radulas) is an anatomical structure used by mollusks for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters ...
to drill a hole through the shell, then inject venom and digestive enzymes through the hole, after which the digested prey can be sucked out through the hole.
* The larvae of
glowworm
Glowworm or glow-worm is the common name for various groups of insect larvae and adult larviform females that glow through bioluminescence. They include the European common glow-worm and other members of the Lampyridae, but bioluminescence al ...
s and
fireflies
The Lampyridae are a family of elateroid beetles with more than 2,000 described species, many of which are light-emitting. They are soft-bodied beetles commonly called fireflies, lightning bugs, or glowworms for their conspicuous production ...
are simply small enough to enter the shells of terrestrial snails and begin eating immediately.
In marine mammals
Whales
Whales are a widely distributed and diverse group of fully Aquatic animal, aquatic placental mammal, placental marine mammals. As an informal and Colloquialism, colloquial grouping, they correspond to large members of the infraorder Cetacea ...
:
Sperm whales
The sperm whale or cachalot (''Physeter macrocephalus'') is the largest of the toothed whales and the largest toothed predator. It is the only living member of the genus '' Physeter'' and one of three extant species in the sperm whale super ...
,
pilot whales,
Cuvier's beaked whale
Cuvier's beaked whale, goose-beaked whale, or ziphius (''Ziphius cavirostris'') is the most widely distributed of all beaked whales in the family Beaked whale, Ziphiidae. It is smaller than most baleen whales—and indeed the larger Toothed whal ...
,
Risso's dolphin
Risso's dolphin (''Grampus griseus'') is a marine mammal and dolphin, the only species of the genus ''Grampus''. Some of the most closely related species to these dolphins include: pilot whales (''Globicephala'' spp.), pygmy killer whales (''Fere ...
and species in the genera ''
Mesoplodon'', and ''
Hyperoodon'' and the superfamily
Physeteroidea
Physeteroidea is a superfamily (taxonomy), superfamily that includes three extant taxon, extant species of whales: the sperm whale, in the genus ''Physeter'', and the pygmy sperm whale and dwarf sperm whale, in the genus ''Kogia''. In the past, t ...
are classified as molluscivores, eating mainly squid.
Pinnipeds
Pinnipeds (pronounced ), commonly known as seals, are a widely distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammals. They comprise the extant families Odobenidae (whose only living member is the walr ...
:
Elephant seals,
Ross seals and
South American fur seals are classed as molluscivores.
The walrus eats benthic bivalve molluscs, especially
clam
Clam is a common name for several kinds of bivalve mollusc. The word is often applied only to those that are deemed edible and live as infauna, spending most of their lives halfway buried in the sand of the sea floor or riverbeds. Clams h ...
s, 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
The palate () is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity.
A similar structure is found in crocodilians, but in most other tetrapods, the oral and nasal cavities are not truly sep ...
is uniquely vaulted, enabling effective suction.
In fish
Several species of
pufferfish
Tetraodontidae is a family of marine and freshwater fish in the order Tetraodontiformes. The family includes many familiar species variously called pufferfish, puffers, balloonfish, blowfish, blowers, blowies, bubblefish, globefish, swellfis ...
and
loaches
Loaches are ray-finned fishes of the suborder Cobitoidei. They are freshwater, benthic (bottom-dwelling) fish found in rivers and creeks throughout Eurasia and northern Africa. Loaches are among the most diverse groups of fish; the 1249 known sp ...
are molluscivores. As many molluscs are protected by a
shell
Shell may refer to:
Architecture and design
* Shell (structure), a thin structure
** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses
Science Biology
* Seashell, a hard outer layer of a marine ani ...
, the feeding techniques applied amongst molluscivore
fish
A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...
are highly specialized and usually divided into two groups: "crushers" and "slurpers." Pufferfish tend to be crushers and will use their
beak
The beak, bill, or rostrum is an external anatomical structure found mostly in birds, but also in turtles, non-avian dinosaurs and a few mammals. A beak is used for pecking, grasping, and holding (in probing for food, eating, manipulating and ...
-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
A snout is the protruding portion of an animal's face, consisting of its nose, mouth, and jaw. In many animals, the structure is called a muzzle, Rostrum (anatomy), rostrum, beak or proboscis. The wet furless surface around the nostrils of the n ...
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
Pharyngeal teeth are teeth in the pharyngeal arch of the throat of cyprinids, suckers, and a number of other fish species otherwise lacking teeth.[trematode
Trematoda is a Class (biology), class of flatworms known as trematodes, and commonly as flukes. They are obligate parasite, obligate Endoparasites, internal parasites with a complex biological life cycle, life cycle requiring at least two Host ( ...](_blank)
parasite in fish reared on fish farms. Two snail-eating
cichlids
Cichlids ()
are a large, diverse, and widespread family of Percomorpha, percomorph fish in the family (biology), family Cichlidae, order Cichliformes. At least 1,760 species have been Binomial nomenclature, scientifically described, making ...
, ''
Trematocranus placodon'' and ''Maravichromis anaphyrmis'', have been tried as biological control agents of
schistosomes in fish ponds in Africa.
Redear sunfish
The redear sunfish (''Lepomis microlophus''), also known as the shellcracker, Georgia bream, cherry gill, chinquapin, improved bream, and sun perch, is a freshwater fish in the family Centrarchidae and is native to the southeastern United States ...
(''Lepomis micropholus'') and
bluegill
The bluegill (''Lepomis macrochirus''), sometimes referred to as "bream", "brim", "sunny", or, in Texas, "copper nose", is a species of North American freshwater fish, native to and commonly found in streams, rivers, lakes, ponds and wetlands ea ...
(''Lepomis macrochirus'') have been used to control
quagga mussel
The quagga mussel (''Dreissena bugensis'') is a species (or subspecies) of freshwater mussel, an aquatic bivalve mollusk in the family Dreissenidae. It has an average lifespan of 3 to 5 years.
The species is indigenous to the Dnipro River dr ...
s (''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".
In reptiles
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.
The prehistoric
placodont
Placodonts (" tablet teeth") are an extinct order of marine reptiles that lived during the Triassic period, becoming extinct at the end of the period. They were part of Sauropterygia, the group that includes plesiosaurs. Placodonts were generall ...
reptiles is an extinct taxon of marine animals that superficially resembled lizards and turtles, most of whose dentition of peg-like incisors and enormous, molar-like teeth allowed them to prey on molluscs and brachiopods by plucking their prey off of the substrate, and crushing the shells.
In birds
Among
birds
Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...
, the eponymous
shorebirds known as
oystercatcher
The oystercatchers are a group of waders forming the family (biology), family Haematopodidae, which has a single genus, ''Haematopus''. They are found on coasts worldwide apart from the polar regions and some tropical regions of Africa and Sout ...
s are renowned for feeding upon bivalves. At least one
bird of prey
Birds of prey or predatory birds, also known as (although not the same as) raptors, are hypercarnivorous bird species that actively predation, hunt and feed on other vertebrates (mainly mammals, reptiles and smaller birds). In addition to speed ...
is also primarily a molluscivore—the
snail kite, ''Rostrhamus sociabilis''. The
limpkin is a small rail-like bird that feeds almost entirely on apple snails. Other birds that will eat molluscs occasionally include
mergansers
''Mergus'' is the genus of the typical mergansers ( ) fish-eating ducks in the subfamily Anatinae. The genus name is a Latin word used by Pliny the Elder and other Ancient Rome, Roman authors to refer to an unspecified waterbird.
The common mer ...
,
ducks
Duck is the common name for numerous species of waterfowl in the family (biology), family Anatidae. Ducks are generally smaller and shorter-necked than swans and goose, geese, which are members of the same family. Divided among several subfam ...
,
coots
Coots are medium-sized water birds that are members of the rail family, Rallidae. They constitute the genus ''Fulica'', the name being the Latin term for "coot". Coots have predominantly black plumage, and—unlike many rails—they are usually ...
,
dippers and
spoonbills.
In invertebrates
Cone snails: Some cone snails hunt and eat other kinds of snails, such as cowries, olive shells, turbo snails, and conch snails, while others will eat other cone snails. ''Conus marmoreus'' and ''Conus omaria'' are able to kill and swallow prey that are larger than themselves; some ''Conus'' species can swallow prey that weigh up to half of their own weight. Snails' bodies are attached to their shell by a columellar muscle that holds onto the
columella
Lucius Junius Moderatus Columella (, Arabic: ) was a prominent Roman writer on agriculture in the Roman Empire.
His in twelve volumes has been completely preserved and forms an important source on Roman agriculture and ancient Roman cuisin ...
, the axis of the snail. This muscle also allows the snail to retract back into its shell. If this muscle is broken, the snail will lose its shell and die. It is hard to detach this muscle in a live snail, or even in a dead snail. It is thought that the
conotoxins in the venom of cone snails are able to completely relax this muscle so that the body can be pulled out from its shell. The cone snail uses its foot to hold the shell of its prey. Using a strong, steady pulling motion, the body of the snail can be forced out and then swallowed whole. Complete digestion of a snail can take many hours, even days.
Starfish
Starfish or sea stars are Star polygon, star-shaped echinoderms belonging to the class (biology), class Asteroidea (). Common usage frequently finds these names being also applied to brittle star, ophiuroids, which are correctly referred to ...
: Primitive starfish, such as ''
Astropecten
''Astropecten'' is a genus of sea stars of the family Astropectinidae.
Identification
These sea stars are similar one to each other and it can be difficult to determine with certainty the species only from a photograph. To have a certain de ...
'' and ''
Luidia
''Luidia'' is a genus of starfish in the family Luidiidae in which it is the only genus. Species of the family have a cosmopolitan distribution.
Characteristics
Members of the genus are characterised by having long arms with pointed tips frin ...
'', swallow their prey whole and start to digest it in their cardiac stomachs. Shell valves and other inedible materials are ejected through their mouths. The semi-digested fluid is passed into their pyloric stomachs and caeca where digestion continues and absorption occurs. The margined sea star (''
Astropecten articulatus'') is a well known molluscivore. It catches prey with its arms which it then takes to the mouth. The prey is then trapped by the long, moving prickles around the mouth cavity and swallowed food.
In more advanced species of starfish, the cardiac stomach can be everted from the organism's body to engulf and digest food. When the prey is a clam, the starfish pulls with its tube feet to separate the two valves slightly, and inserts a small section of its stomach, which releases enzymes to digest the prey. The stomach and the partially digested prey are later retracted into the disc. Here the food is passed on to the pyloric stomach, which always remains inside the disc.
Because of this ability to digest food outside the body, starfish can hunt prey much larger than their mouths.
Crabs
Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tailed" in Greek), which typically have a very short projecting tail-like abdomen, usually hidden entirely under the thorax. Their exoskeleton is often thickened and ha ...
: The
freshwater crabs ''Syntripsa matannensis'' and ''Syntripsa flavichela'' are classed as molluscivores. Using their massive and powerful claws, adult
Florida stone crabs (''Menippe mercenaria'') feed on
acorn barnacles, hard-shelled clams,
scallops
Scallop () is a common name that encompasses various species of marine bivalve molluscs in the taxonomic family Pectinidae, the scallops. However, the common name "scallop" is also sometimes applied to species in other closely related famili ...
, and
conch
Conch ( , , ) is a common name of a number of different medium-to-large-sized sea snails. Conch shells typically have a high Spire (mollusc), spire and a noticeable siphonal canal (in other words, the shell comes to a noticeable point on both ...
.
[Williams, A., (1984). ''Shrimps, lobsters, and crabs of the Atlantic coast of the Eastern United States, Maine to Florida''. Washington, D. C.: Smithsonian Institution.]
References
{{Ethology
Carnivory
Mollusc ecology
Biology terminology
Animals by eating behaviors