The capybara, or Hydrochoerus hydrochaeris, is the largest living rodent in the world, thriving in the warm, semi-aquatic environments of South America. These large herbivores spend their lives near bodies of water, such as rivers, swamps, and lakes, across countries like Brazil, Venezuela, and Colombia. They are strictly herbivorous, consuming large quantities of plant matter daily to sustain their size. Their feeding habits are closely linked to their aquatic habitats.
Staple Diet: Grasses and Aquatic Plants
The bulk of a capybara’s diet consists of grasses and aquatic vegetation, reflecting their grazing behavior and preference for water-adjacent areas. An adult capybara can consume between 6 to 8 pounds of fresh vegetation daily to meet its energy needs. They are highly selective feeders during the wet season, choosing plant species that offer the best nutritional value, particularly those with higher energy and crude protein content.
Specific aquatic grasses, such as Hymenachne amplexicaulis, are favored due to their high palatability and nutrient density. They also graze on other grasses like Reimarochloa acuta and Paratheria prostrata. Their large, continually growing incisors are perfectly adapted for clipping these tough, fibrous plants.
Capybaras also consume various aquatic plants like water hyacinths and water lettuce, which are readily available in their wetland habitats. Feeding on aquatic vegetation provides a dual benefit: nutrition and hydration. In some regions, aquatic plants can comprise up to 87% of their total diet. The constant presence of water allows them to access these plants and escape predators while feeding.
Seasonal Foraging and Supplemental Foods
The capybara’s diet adapts significantly in response to the distinct wet and dry seasons of their range. During the wet season, when grasses are abundant and nutrient-rich, they can afford to be highly selective. However, the dry season presents a challenge as the preferred soft grasses and aquatic plants dry up or become scarce.
When their staple foods diminish, capybaras become less choosy and must broaden their foraging efforts. They turn to secondary food sources, which include tougher, less digestible plant materials like reeds and the bark of specific trees. This shift in diet ensures they maintain their caloric intake.
Supplemental foods like tubers, fruits, and seeds are also consumed opportunistically when available. If their territory borders human settlements, capybaras may forage on crops such as grains, melons, and squashes. These items serve as energy supplements, providing nutrients that may be lacking in the sparse, dry grasses and woody vegetation.
Specialized Digestive Habits
Capybaras are hindgut fermenters, a digestive strategy that allows them to process their high-cellulose diet effectively. Unlike ruminants, which have a multi-chambered stomach, the capybara relies on a greatly enlarged cecum for microbial fermentation. The cecum is a large pouch located at the junction of the small and large intestines, and it can account for a significant portion of the gastrointestinal tract.
Within the cecum, specialized microorganisms break down the complex cellulose found in grasses into digestible nutrients. This fermentation process also produces B vitamins and Vitamin K. The capybara’s digestive efficiency is comparable to that of ruminant animals, allowing them to thrive on a forage-only diet.
To extract the maximum nutritional benefit from their fibrous meals, capybaras engage in autocoprophagy, or the consumption of their own feces. They re-ingest specialized soft droppings, or cecotropes, usually in the early morning. These soft feces are packed with protein, vitamins, and undigested plant material that has been processed by the cecal microbes. By consuming the cecotropes, the capybara gains a second opportunity to absorb the nutrients missed during the first pass.