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Feeding is the process by which organisms, typically animals, obtain food. Terminology often uses either the suffix -vore from Latin vorare, meaning 'to devour', or phagy, from Greek φαγειν, meaning 'to eat'.

Evolutionary history[]

The evolution of different feeding strategies 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).[1]

Evolutionary adaptations[]

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


Method of feeding[]

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 and suction feeding - ingesting prey via the fluids around it.

By mode of digestion[]

  • Extra-cellular digestion - excreting digesting enzymes and then reabsorbing the products
  • Myzocytosis - one cell pierces another using a feeding tube, and sucks out cytoplasm
  • Phagocytosis - 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).

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

  • Carnivore - the eating of animals
    • Haematophagy - eating blood
    • Insectivore - eating insects
      • Myrmecophagy - eating ants and/or termites
    • Keratophagy or Ceratophagy - eating horny material, such as wool by cloths moths, or snakes eating their own skin after ecdysis.
    • Lepidophagy - eating fish scales
    • Man-eater - eating humans
    • Molluscivore - eating molluscs
    • Mucophagy - eating mucus
    • Ophiophagy - eating snakes
    • Piscivore - eating fish
    • Avivore - eating birds
    • Spongivore - eating sponges
  • Herbivore - the eating of plants
    • Folivore - eating leaves
    • Frugivore - eating fruits
    • Graminivore - eating grasses
    • Granivore - eating seeds
    • Nectarivore - eating nectar
    • Palynivore - eating pollen
    • Xylophagy - eating wood
  • Omnivore - the eating of both plants and animals
  • Fungivore - the eating of fungus
  • Bacterivore - the eating of bacteria

The eating of non-living or decaying matter:

  • Coprophagy - eating faeces
  • Detritivore - eating decomposing material
  • Geophagy - eating inorganic earth
  • Osteophagy - eating bones
  • Scavenger - eating carrion

There are also several unusual feeding behaviours, either normal, opportunistic, or pathological, such as:

  • Cannibalism - feeding on members of the same species
  • Self-cannibalism - feeding on parts of one's own body (see also autophagy)
  • Sexual cannibalism - cannibalism after mating
  • Kleptoparasitism - stealing food from another animal
  • Trophallaxis - eating food regurgitated by another animal
  • Oophagy - eating eggs
  • Ovophagy - eating embryos
  • Paedophagy - eating young animals
  • Pica - appetite for largely non-nutritive substances, eg clay or hair, sometimes in pregnancy or in pathological states, typically a medical or veterinary concern.
  • Placentophagy - eating placenta

An opportunistic feeder sustains itself from a number of different food sources, because the species is behaviorally sufficiently flexible.

Storage behaviours[]

Some animals exhibit hoarding and caching behaviours in which they store or hide food for later use.

See also[]

References & Bibliography[]

  1. Sahney, S., Benton, M.J. & Falcon-Lang, H.J. (2010). Rainforest collapse triggered Pennsylvanian tetrapod diversification in Euramerica. Geology 38 (12): 1079–1082.

Key texts[]



Additional material[]



External links[]

File:Anopheles stephensi.jpeg

Mosquito drinking blood

File:Rosy boa eating.JPG

Rosy boa eating a mouse whole


Red Kangaroo eating grass

File:Pegesimallus sp robberfly.jpg

The robberfly is an insectivore

Robin eating a worm in spring

Robin eating a worm


Hummingbird drinking nectar


Krill filter feeding

File:Myrmicaria brunnea.jpg

Myrmicaria brunnea feeding on sugar crystals

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