The capybara (Hydrochoerus hydrochaeris) is the world’s largest rodent, a semi-aquatic mammal native to South America. Weighing up to 140 pounds, this giant guinea pig relative is a dedicated herbivore. Capybaras spend considerable time grazing along the edges of water bodies, consuming massive quantities of high-fiber plant matter.
Primary Food Sources
The capybara’s diet is overwhelmingly composed of grasses and aquatic vegetation, forming a high-fiber foundation. A single adult consumes approximately 6 to 8 pounds of fresh grass daily, a requirement driven by the low caloric density of their preferred forage. They are highly selective grazers, often choosing specific high-caloric, low-fiber plant species.
Their favorite foods include aquatic grasses, such as Hymenachne amplexicaulis, and various sedges (Cyperaceae) and panic grasses (Panicum spp.) that thrive in wetland habitats. During the wet season, when fresh grasses are abundant and nutrient-rich, this selective grazing behavior ensures they maximize nutrient uptake from the tough, fibrous material.
Specialized Digestive Anatomy
Processing a diet of tough, silica-rich grasses necessitates a highly specialized digestive system and dental structure. Capybaras are classified as non-ruminant hindgut fermenters, meaning the majority of fiber digestion takes place in the large intestine, particularly the massive cecum and colon. Symbiotic bacteria within this chamber break down structural cellulose, releasing volatile fatty acids the capybara absorbs as energy.
The constant grinding required for this fibrous food causes significant wear on their teeth, so their incisors and cheek teeth grow continuously throughout their lives. To maximize nutritional yield, capybaras engage in coprophagy, or the consumption of their own nutrient-rich fecal pellets. These soft, specialized pellets are re-ingested to recover proteins, B vitamins, and other nutrients produced during the fermentation process that were not absorbed during the first pass.
Dietary Shifts Based on Season
While grasses are their preferred food, the capybara’s diet exhibits flexibility dictated by the alternating wet and dry seasons of their environment. During the lush wet season, they focus their grazing on the most palatable and nutritious grasses. However, as the dry season progresses, preferred grasses become drier, less abundant, and lower in nutritional value.
When their staple diet diminishes, capybaras become opportunistic foragers and turn to secondary food sources. This seasonal shift includes consuming tougher, more fibrous items like soft tree bark, reeds, aquatic roots, and tubers. Eating less-preferred plants means they must spend a greater portion of the day grazing during the dry season to meet their daily caloric requirements.