Feeding is the process by which organisms, typically

animal Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motilit ...

s, obtain

food Food is any substance consumed by an organism for nutritional support. Food is usually of plant, animal, or fungal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is ...

. Terminology often uses either the suffixes -vore, -vory, or -vorous from Latin ''vorare'', meaning "to devour", or -phage, -phagy, or -phagous from Greek φαγεῖν (), meaning "to eat".

Evolutionary history

The evolution of feeding is varied with some feeding strategies evolving several times in independent lineages. In terrestrial vertebrates, the earliest forms were large amphibious piscivores 400 million years ago. While amphibians continued to feed on fish and later insects, reptiles began exploring two new food types, other tetrapods (carnivory), and later, plants (herbivory). Carnivory was a natural transition from insectivory for medium and large tetrapods, requiring minimal adaptation (in contrast, a complex set of adaptations was necessary for feeding on highly fibrous plant materials).

Evolutionary adaptations

The specialization of organisms towards specific food sources is one of the major causes of

evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

of form and function, such as: *

mouth In animal anatomy, the mouth, also known as the oral cavity, or in Latin cavum oris, is the opening through which many animals take in food and issue vocal sounds. It is also the cavity lying at the upper end of the alimentary canal, bounded on t ...

parts and

teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, te ...

, such as in

whale Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...

vampire bat Vampire bats, species of the subfamily Desmodontinae, are leaf-nosed bats found in Central and South America. Their food source is blood of other animals, a dietary trait called hematophagy. Three extant bat species feed solely on blood: the c ...

leech Leeches are segmented parasitic or predatory worms that comprise the subclass Hirudinea within the phylum Annelida. They are closely related to the oligochaetes, which include the earthworm, and like them have soft, muscular segmented b ...

es,

mosquito Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning "gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "lit ...

s, predatory animals such as

feline Feline may refer to: Zoology * Loosely, Felidae, a member of the cat family, which includes the subfamilies Pantherinae and Felinae (conventionally designated a felid) ** Following the taxonomic convention, Felinae, the subfamily of Felidae that ...

s and

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% ...

es, etc. * distinct forms of

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 eating, preening, manipulating objects, killing prey, fighting, probing for fo ...

s in

birds Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

, such as in

hawk Hawks are birds of prey of the family Accipitridae. They are widely distributed and are found on all continents except Antarctica. * The subfamily Accipitrinae includes goshawks, sparrowhawks, sharp-shinned hawks and others. This subfa ...

s, woodpeckers,

pelican Pelicans (genus ''Pelecanus'') are a genus of large water birds that make up the family Pelecanidae. They are characterized by a long beak and a large throat pouch used for catching prey and draining water from the scooped-up contents before ...

hummingbird Hummingbirds are birds native to the Americas and comprise the biological family Trochilidae. With about 361 species and 113 genera, they occur from Alaska to Tierra del Fuego, but the vast majority of the species are found in the tropics ar ...

parrot Parrots, also known as psittacines (), are birds of the roughly 398 species in 92 genera comprising the order Psittaciformes (), found mostly in tropical and subtropical regions. The order is subdivided into three superfamilies: the Psittaco ...

kingfisher Kingfishers are a family, the Alcedinidae, of small to medium-sized, brightly colored birds in the order Coraciiformes. They have a cosmopolitan distribution, with most species found in the tropical regions of Africa, Asia, and Oceania ...

s, etc. * specialized

claw A claw is a curved, pointed appendage found at the end of a toe or finger in most amniotes (mammals, reptiles, birds). Some invertebrates such as beetles and spiders have somewhat similar fine, hooked structures at the end of the leg or tars ...

s and other appendages, for apprehending or killing (including fingers in

primate Primates are a diverse order (biology), order of mammals. They are divided into the Strepsirrhini, strepsirrhines, which include the lemurs, galagos, and lorisids, and the Haplorhini, haplorhines, which include the Tarsiiformes, tarsiers and ...

s) * changes in body colour for facilitating

camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...

, disguise, setting up traps for preys, etc. * changes in the digestive system, such as the system of

stomach The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach i ...

s of herbivores,

commensalism Commensalism is a long-term biological interaction ( symbiosis) in which members of one species gain benefits while those of the other species neither benefit nor are harmed. This is in contrast with mutualism, in which both organisms benefit fr ...

and symbiosis

Classification

By mode of ingestion

There are many modes of feeding that animals exhibit, including: * Filter feeding: obtaining nutrients from particles suspended in water * Deposit feeding: obtaining nutrients from particles suspended in soil * Fluid feeding: obtaining nutrients by consuming other organisms' fluids *Bulk feeding: obtaining nutrients by eating all of an organism. *

Ram feeding Aquatic feeding mechanisms face a special difficulty as compared to feeding on land, because the density of water is about the same as that of the prey, so the prey tends to be pushed away when the mouth is closed. This problem was first identifi ...

and

suction feeding Aquatic feeding mechanisms face a special difficulty as compared to feeding on land, because the density of water is about the same as that of the prey, so the prey tends to be pushed away when the mouth is closed. This problem was first identifi ...

: ingesting prey via the fluids around it.

By mode of digestion

Extra-cellular digestion Extracellular phototropic digestion is a process in which saprobionts feed by secreting enzymes through the cell membrane onto the food. The enzymes catalyze the digestion of the food ie diffusion, transport, osmotrophy or phagocytosis. Since diges ...

: excreting digesting enzymes and then reabsorbing the products * Myzocytosis: one cell pierces another using a feeding tube, and sucks out cytoplasm *

Phagocytosis Phagocytosis () is the process by which a cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs phagocytosis i ...

: engulfing food matter into living cells, where it is digested

By food type

Polyphagy is the ability of an animal to eat a variety of food, whereas monophagy is the intolerance of every food except of one specific type (see

generalist and specialist species A generalist species is able to thrive in a wide variety of environmental conditions and can make use of a variety of different resources (for example, a heterotroph with a varied diet). A specialist species can thrive only in a narrow range of ...

). Another classification refers to the specific food animals specialize in eating, such as: *

Carnivore A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other ...

: the eating of animals ** Araneophagy: eating spiders ** Avivore: eating birds ** Corallivore: eating coral ** Durophagy: eating hard-shelled or

exoskeleton An exoskeleton (from Greek ''éxō'' "outer" and ''skeletós'' "skeleton") is an external skeleton that supports and protects an animal's body, in contrast to an internal skeleton ( endoskeleton) in for example, a human. In usage, some of the ...

bearing organisms **

Egg predator Egg predation is a feeding strategy in many groups of animals (ovivores) in which they consume eggs. Since an egg represents a complete organism at one stage of its life cycle, eating an egg is a form of predation, the killing of another organism ...

: eating eggs (but also see " Intrauterine cannibalism" below), also

Ovivore Egg predation is a feeding strategy in many groups of animals (ovivores) in which they consume eggs. Since an egg represents a complete organism at one stage of its life cycle, eating an egg is a form of predation, the killing of another organism ...

** Haematophage/Sanguivore: eating blood **

Insectivore A robber fly eating a hoverfly An insectivore is a carnivorous animal or plant that eats insects. An alternative term is entomophage, which can also refer to the human practice of eating insects. The first vertebrate insectivores wer ...

: eating insects *** Myrmecophage: eating ants and/or termites ** Invertivore: eating

invertebrates Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

Keratophagy This glossary of entomology describes terms used in the formal study of insect species by entomologists. A–C A synthetic chlorinated hydrocarbon insecticide, toxic to vertebrates. Though i ...

or Ceratophagy: eating horny material, such as wool by cloths moths, or snakes eating their own skin after

ecdysis Ecdysis is the moulting of the cuticle in many invertebrates of the clade Ecdysozoa. Since the cuticle of these animals typically forms a largely inelastic exoskeleton, it is shed during growth and a new, larger covering is formed. The remnan ...

. ** Lepidophagy: eating fish scales ** Molluscivore: eating molluscs ** Mucophagy: eating mucus ** Ophiophagy: eating snakes ** Piscivore: eating fish ** Anurophagy: eating frogs ** Spongivore: eating sponges ** Teuthophagore: eating mainly squid and other cephalopods ** Vermivore: eating worms ** Zooplanktonivore: eating zooplankton *

Herbivore A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthp ...

: the eating of plants ** Exudativore: eating plant and/or insect exudates (gum, sap, lerp, etc.) *** Gumivore: eating tree gum ** Folivore: eating leaves ** Florivore: eating flower tissue prior to seed coat formation **

Frugivore A frugivore is an animal that thrives mostly on raw fruits or succulent fruit-like produce of plants such as roots, shoots, nuts and seeds. Approximately 20% of mammalian herbivores eat fruit. Frugivores are highly dependent on the abundance an ...

: eating fruits ** Graminivore: eating grasses ** Granivore: eating seeds **

Nectarivore In zoology, a nectarivore is an animal which derives its energy and nutrient requirements from a diet consisting mainly or exclusively of the sugar-rich nectar produced by flowering plants. Nectar as a food source presents a number of benefit ...

: eating nectar **

Palynivore In zoology, a palynivore /pəˈlɪnəvɔːɹ/, meaning "pollen eater" (from Greek παλύνω palunō, "strew, sprinkle", and Latin, vorare, meaning "to devour") is an herbivorous animal which selectively eats the nutrient-rich pollen produced b ...

: eating pollen ** Phytoplanktonivore: eating

phytoplankton Phytoplankton () are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater ecosystems. The name comes from the Greek words (), meaning 'plant', and (), meaning 'wanderer' or 'drifter'. P ...

** Xylophage: eating wood *

Omnivore An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nut ...

: the eating of both plants, animals, fungi, bacteria etc. The term means "all-eater". * By amount of meat in diet ** Hypercarnivore: more than 70% meat ** Mesocarnivore: 30–70% meat ** Hypocarnivore: less than 30% meat * Fungivore: the eating of fungus * Bacterivore: the eating of bacteria The eating of non-living or decaying matter: * Coprophage: eating faeces * Detritivore: eating decomposing material * Geophagia: eating inorganic earth * Osteophage: eating bones * Saprophage: eating decaying organic matter *

Scavenger Scavengers are animals that consume dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a herbivorous feeding b ...

: eating carrion There are also several unusual feeding behaviours, either normal,

opportunistic Opportunism is the practice of taking advantage of circumstances – with little regard for principles or with what the consequences are for others. Opportunist actions are expedient actions guided primarily by self-interested motives. The term ...

, or pathological, such as: *

Cannibalism Cannibalism is the act of consuming another individual of the same species as food. Cannibalism is a common ecological interaction in the animal kingdom and has been recorded in more than 1,500 species. Human cannibalism is well documented, b ...

: feeding on members of the same species ** Anthropophagy: the practice of eating

human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...

flesh ** Intrauterine cannibalism ***

Oophagy Oophagy ( ) sometimes ovophagy, literally "egg eating", is the practice of embryos feeding on eggs produced by the ovary while still inside the mother's uterus. The word oophagy is formed from the classical Greek (, "egg") and classical Greek ( ...

Ovophagy Oophagy ( ) sometimes ovophagy, literally "egg eating", is the practice of embryos feeding on eggs produced by the ovary while still inside the mother's uterus. The word oophagy is formed from the classical Greek (, "egg") and classical Greek (, ...

: the embryo/foetus eats sibling eggs *** Embryophagy: the foetus eats sibling embryos ** Filial cannibalism ** Self-cannibalism: feeding on parts of one's own body (see also

autophagy Autophagy (or autophagocytosis; from the Ancient Greek , , meaning "self-devouring" and , , meaning "hollow") is the natural, conserved degradation of the cell that removes unnecessary or dysfunctional components through a lysosome-dependent re ...

) ** Sexual cannibalism: cannibalism after mating *

Kleptoparasitism Kleptoparasitism (etymologically, parasitism by theft) is a form of feeding in which one animal deliberately takes food from another. The strategy is evolutionarily stable when stealing is less costly than direct feeding, which can mean when fo ...

: stealing food from another animal * Kleptopharmacophagy: act of stealing chemical compounds for consumption * Lignophagia: eating wood, typically a pathological condition in some domestic animals * Paedophagy: eating young animals * Pica: appetite for largely non-nutritive substances, e.g. clay or hair, sometimes in pregnancy or in pathological states, typically a medical or veterinary concern. * Placentophagy: eating placenta * Trophallaxis: eating food regurgitated by another animal * Zoopharmacognosy:

self-medication Self-medication is a human behavior in which an individual uses a substance or any exogenous influence to self-administer treatment for physical or psychological conditions: for example headaches or fatigue. The substances most widely used in sel ...

by eating

plant Plants are predominantly Photosynthesis, photosynthetic eukaryotes of the Kingdom (biology), kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all curr ...

soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former ...

s, and

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs ...

s to treat and prevent disease. An opportunistic feeder sustains itself from a number of different food sources, because the species is behaviourally sufficiently flexible.

Storage behaviours

Some animals exhibit hoarding and

caching In computing, a cache ( ) is a hardware or software component that stores data so that future requests for that data can be served faster; the data stored in a cache might be the result of an earlier computation or a copy of data stored elsewher ...

behaviours in which they store or hide food for later use.

References

Notes

{{Feeding * Ethology af:Voeding pt:Alimentação