Herbivore

Herbivore, an animal that subsists solely on vegetation. In the food web, herbivores are primary consumers, eating plants which absorb and store energy from the Sun through photosynthesis. In turn, the herbivores are preyed upon by carnivores.

Herbivore, unlike carnivore, is a purely descriptive term and does not apply to any one particular group in animal taxonomy.

Although the term herbivore encompasses many types of animal it is mostly used for the ungulates; large, hoofed mammals, such as elephants, sheep, and horses.

Similarities in digestive systems occur, arising from the need to digest the cellulose in tough plant material. Differentiations in physiology reflect individual species' diet. Adaptations include the high-crowned, hard-wearing, flat, grinding molars of ungulates. Rodents, such as beavers, have large, continuously growing, chisel-shaped incisors to gnaw plant bark. Snails use a radula, a small, spiky, rasping organ to tear off tiny fragments of leaf. The ruminants, for example, cows and sheep, possess a four-chambered stomach housing micro-organisms that break down the cellulose into a more digestible form, obtaining food and shelter in the stomach in return.

Although most herbivores have a degree of variety in their diets, some are restricted to one type of food and are known as monophagous herbivores. The koala, for example, exists solely on eucalyptus.