grazers

Grazers are herbivorous animals whose diet consists largely of grasses and other low-growing herbaceous plants. The term contrasts with browsers, which feed mainly on leaves, shoots, and branches of shrubs and trees. While many mammals are grazers, grazing is a feeding strategy found across several taxonomic groups, including some birds and insects. In mammals, grazers tend to forage in open habitats such as plains, savannas, and prairies, though they also exploit forage in wetlands and at habitat edges.

Adaptations common to grazers include dentition suited to processing fibrous plant matter, such as high-crowned hypsodont teeth; specialized digestive systems like ruminant multi-chamber stomachs or hindgut fermentation that help extract nutrients from cellulose. Foraging behavior often involves selecting for forage that optimizes nutrient intake, with a preference for grasses’ younger shoots or high-quality grass leaves and stems.

Ecologically, grazers influence plant communities, fire regimes, and nutrient cycling in grassland ecosystems. Large grazing mammals can suppress woody plant expansion, promote dominant grasses, and foster habitat heterogeneity. They often participate in migrations and seasonal movements that shape energy flow and predator–prey dynamics. Domestic grazers, such as cattle, sheep, and horses, support agriculture and land management; wildlife grazers include species like wildebeest, zebra, bison, and various antelope. While grazing can be sustainable at moderate intensities, overgrazing and habitat loss threaten grassland ecosystems.