PREVIOUS YEAR QUESTIONS| NUTRITION & DIETETICS|L-20

Feeding is the process by which organisms, typically animals, obtain food. Terminology often uses either the suffixes -vore, -vory, or -vorous from Latin vorare, meaning “to devour”, or -phage, -phagy, or -phagous from Greek φαγεῖν (phagein), 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

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The specialization of organisms towards specific food sources is one of the major causes of evolution of form and function, such as:

mouth parts and teeth, such as in whales, vampire bats, leeches, mosquitos, predatory animals such as felines and fishes, etc.

distinct forms of beaks in birds, such as in hawks, woodpeckers, pelicans, hummingbirds, parrots, kingfishers, etc.

specialized claws and other appendages, for apprehending or killing (including fingers in primates)

changes in body colour for facilitating camouflage, disguise, setting up traps for preys, etc.

changes in the digestive system, such as the system of stomachs of herbivores, commensalism and symbiosis

Classification

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

Carnivore: the eating of animals

Araneophagy: eating spiders

Avivore: eating birds

Corallivore: eating coral

Durophagy: eating hard-shelled or exoskeleton bearing organisms

Egg predator: eating eggs (but also see “Intrauterine cannibalism” below), also Ovivore

Haematophage/Sanguivore: eating blood

Insectivore: eating insects

Myrmecophage: eating ants and/or termites

Invertivore: eating invertebrates

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

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: 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: eating fruits

Graminivore: eating grasses

Granivore: eating seeds

Nectarivore: eating nectar

Palynivore: eating pollen

Phytoplanktonivore: eating phytoplankton

Xylophage: eating wood

Omnivore: 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: eating carrion