zoology Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the Animal, animal kingdom, including the anatomy, structure, embryology, evolution, Biological clas ...

, a folivore is a

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 mouthpart ...

that specializes in eating

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

. Mature leaves contain a high proportion of hard-to-digest

cellulose Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell w ...

, less energy than other types of foods, and often toxic compounds.Jones, S., Martin, R., & Pilbeam, D. (1994) ''The Cambridge Encyclopedia of Human Evolution''. Cambridge: Cambridge University Press For this reason, folivorous animals tend to have long

digestive tract The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and ...

s and slow metabolisms. Many enlist the help of symbiotic bacteria to release the nutrients in their diet. Additionally, as has been observed in folivorous primates, they exhibit a strong preference for immature leaves, which tend to be easier to

masticate Chewing or mastication is the process by which food is crushed and ground by teeth. It is the first step of digestion, and it increases the surface area of foods to allow a more efficient break down by enzymes. During the mastication process, t ...

, tend to be higher in energy and protein, and lower in fibre and

poisons Poison is a chemical substance that has a detrimental effect to life. The term is used in a wide range of scientific fields and industries, where it is often specifically defined. It may also be applied colloquially or figuratively, with a broa ...

than more mature fibrous leaves.

Evolution

Herbivory has evolved several times among different groups of animals. The first vertebrates were small fish that consumed protists and invertebrates. After these fish, the next group of vertebrates to evolve were

piscivores A piscivore () is a carnivorous animal that eats primarily fish. The name ''piscivore'' is derived . Piscivore is equivalent to the Greek-derived word ichthyophage, both of which mean "fish eater". Fish were the diet of early tetrapod evolut ...

, then

insectivores 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 were ...

carnivores 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 so ...

and finally

herbivores 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 mouthpart ...

. Since a complex set of adaptations was necessary for feeding on highly fibrous plant materials (structural modifications to the teeth, jaws, and digestive tract) and only a small proportion of extant tetrapods are obligate herbivores, it could be that early tetrapods made the transition to fully fledged herbivory by way of omnivory.

Folivory and flight

It has been observed that folivory is extremely rare among flying vertebrates.Do the Power Requirements of Flapping Flight Constrain Folivory in Flying Animals?
R. Dudley, G. J. Vermeij ''Functional Ecology'', Vol. 6, No. 1 (1992), pp. 101-104 Morton (1978) attributed this to the fact that leaves are heavy, slow to digest, and contain little energy relative to other foods. The

hoatzin The hoatzin ( ) or hoactzin ( ), (''Opisthocomus hoazin''), is the only species in the order Opisthocomiformes. It is a species of tropical bird found in swamps, riparian forests, and mangroves of the Amazon and the Orinoco basins in South Ameri ...

is an example of a flighted, folivorous bird. There are, however, many species of folivorous flying insects. Some

bat Bats are mammals of the order Chiroptera.''cheir'', "hand" and πτερόν''pteron'', "wing". With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most ...

s are partially folivorous; their method of deriving nourishment from leaves, according to Lowry (1989), is to chew up the leaves, swallowing the

sap Sap is a fluid transported in xylem cells (vessel elements or tracheids) or phloem sieve tube elements of a plant. These cells transport water and nutrients throughout the plant. Sap is distinct from latex, resin, or cell sap; it is a separ ...

and spitting out the remainder.

Arboreal folivores

Arboreal Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally, but others are exclusively arboreal. The habitats pose nu ...

mammalian folivores, such as

sloth Sloths are a group of Neotropical xenarthran mammals constituting the suborder Folivora, including the extant arboreal tree sloths and extinct terrestrial ground sloths. Noted for their slowness of movement, tree sloths spend most of their li ...

koala The koala or, inaccurately, koala bear (''Phascolarctos cinereus''), is an arboreal herbivorous marsupial native to Australia. It is the only extant representative of the family Phascolarctidae and its closest living relatives are the w ...

s, and some species of

monkey Monkey is a common name that may refer to most mammals of the infraorder Simiiformes, also known as the simians. Traditionally, all animals in the group now known as simians are counted as monkeys except the apes, which constitutes an incomple ...

s and

lemur Lemurs ( ) (from Latin ''lemures'' – ghosts or spirits) are Strepsirrhini, wet-nosed primates of the Superfamily (biology), superfamily Lemuroidea (), divided into 8 Family (biology), families and consisting of 15 genera and around 100 exist ...

s, tend to be large and climb cautiously.Cautious climbing and folivory: a model of hominoid differentation
E. E. Sarmiento1 in ''Human Evolution'' Volume 10, Number 4, August, 1995 Similarities in body shape and head- and tooth-structure between early

hominoid Apes (collectively Hominoidea ) are a clade of Old World simians native to sub-Saharan Africa and Southeast Asia (though they were more widespread in Africa, most of Asia, and as well as Europe in prehistory), which together with its sister g ...

s and various families of arboreal folivores have been advanced as evidence that early hominoids were also folivorous.

Primates

Standard

ecological theory Theoretical ecology is the scientific discipline devoted to the study of ecological systems using theoretical methods such as simple conceptual models, mathematical models, computational simulations, and advanced data analysis. Effective models im ...

predicts relatively large group sizes for folivorous

primate Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians ( monkeys and apes, the latter including ...

s, as large groups offer better collective defense against predators and they face little competition for food among each other. It has been observed that these animals nevertheless frequently live in small groups. Explanations offered for this apparent paradox include social factors such as increased incidence of

infanticide Infanticide (or infant homicide) is the intentional killing of infants or offspring. Infanticide was a widespread practice throughout human history that was mainly used to dispose of unwanted children, its main purpose is the prevention of reso ...

in large groups. Alouatta-caraya ppia-m01b

Folivorous primates are relatively rare in the

New World The term ''New World'' is often used to mean the majority of Earth's Western Hemisphere, specifically the Americas."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: Oxford University Press, p. 3 ...

, the primary exception being

howler monkey Howler monkeys (genus ''Alouatta'', monotypic in subfamily Alouattinae) are the most widespread primate genus in the Neotropics and are among the largest of the platyrrhines along with the muriquis (''Brachyteles''), the spider monkeys (''Atele ...

s. One explanation that has been offered is that fruiting and leafing occur simultaneously among New World plants. However a 2001 study found no evidence for simultaneous fruiting and leafing at most sites, apparently disproving this hypothesis.

Examples

Examples of folivorous animals include: * Mammals:

okapi The okapi (; ''Okapia johnstoni''), also known as the forest giraffe, Congolese giraffe, or zebra giraffe, is an artiodactyl mammal that is endemic to the northeast Democratic Republic of the Congo in central Africa. It is the only species ...

elephant Elephants are the largest existing land animals. Three living species are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant. They are the only surviving members of the family Elephantidae ...

possums Possum may refer to: Animals * Phalangeriformes, or possums, any of a number of arboreal marsupial species native to Australia, New Guinea, and Sulawesi ** Common brushtail possum (''Trichosurus vulpecula''), a common possum in Australian urban a ...

giant pandas The giant panda (''Ailuropoda melanoleuca''), also known as the panda bear (or simply the panda), is a bear species endemic to China. It is characterised by its bold black-and-white coat and rotund body. The name "giant panda" is sometimes use ...

s and various species of

, i.e. New World howlers and Old World colobines * Birds: The

of the Amazon region and the kakapo of New Zealand * Reptiles:

iguana ''Iguana'' (, ) is a genus of herbivorous lizards that are native to tropical areas of Mexico, Central America, South America, and the Caribbean. The genus was first described in 1768 by Austrian naturalist Josephus Nicolaus Laurenti in his ...

s * Insects: various kinds of

caterpillar Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder Sym ...

sawflies Sawflies are the insects of the suborder Symphyta within the order Hymenoptera, alongside ants, bees, and wasps. The common name comes from the saw-like appearance of the ovipositor, which the females use to cut into the plants where they lay ...

beetle Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...

leaf miner A leaf miner is any one of numerous species of insects in which the larval stage lives in, and eats, the leaf tissue of plants. The vast majority of leaf-mining insects are moths ( Lepidoptera), sawflies ( Symphyta, the mother clade of wasp ...

s and Orthoptera * Others: many land gastropod species (snails and slugs)

References

External links

wordquests.info
{{feeding Herbivory Animals by eating behaviors