Capybara

The capybara or greater capybara is the largest living rodent, native to South America. It is a member of the genus Hydrochoerus. The only other extant member is the lesser capybara. Its close relatives include guinea pigs and rock cavies, and it is more distantly related to the agouti, the chinchilla, and the nutria. The capybara inhabits savannas and dense forests, and lives near bodies of water. It is a highly social species and can be found in groups as large as one hundred individuals, but usually live in groups of 10–20 individuals. The capybara is hunted for its meat and hide and also for grease from its thick fatty skin.

Capybaras are predominantly crepuscular, being most active at dawn and dusk, though activity patterns can shift in response to human disturbance or predation risk. They spend much of their time grazing on grasses, reeds, and aquatic plants, consuming up to 3–4 kg (6.6–8.8 lbs) of vegetation daily. Feeding is often communal, with individuals maintaining close proximity and coordinated movement. Social structure is hierarchical, with a dominant male leading the group, supported by subordinate males, females, and juveniles. Social bonds are reinforced through grooming, vocalizations, and scent-marking using specialized glands on the nose (morro) and anus. Capybaras are highly vigilant, posting sentinels while others feed or rest. When threatened, they emit alarm barks and retreat to water, where they can evade terrestrial predators. Daily routines include basking, wallowing in mud to regulate body temperature and deter parasites, and resting in shaded areas during the heat of the day.

Capybaras breed year-round in equatorial regions, but reproduction is often synchronized with the rainy season in more seasonal habitats. Mating occurs in water, with dominant males pursuing receptive females. Gestation lasts approximately 150 days, after which females give birth to 2–8 precocial young, typically on land in dense vegetation. Neonates are well-developed, able to follow the mother and graze within a week, though they nurse for up to 16 weeks. Alloparental care is common, with multiple females in a group nursing and protecting the young. Juvenile survival is enhanced by group vigilance and the use of aquatic refuges. Sexual maturity is reached at 12–18 months, and females may produce up to two litters per year under favorable conditions.

Capybaras possess several adaptations for a semi-aquatic lifestyle: their eyes, ears, and nostrils are positioned dorsally, allowing them to remain mostly submerged while monitoring their surroundings. The partially webbed feet facilitate efficient swimming and movement through marshy terrain. Dense, greasy fur resists water penetration, and a thick layer of subcutaneous fat provides buoyancy and insulation. Their digestive system is specialized for processing fibrous plant material, with an enlarged cecum and colon for microbial fermentation. Coprophagy enables them to extract maximum nutrients from their diet. Behavioral adaptations include group living for enhanced predator detection and the use of vocal and chemical communication to coordinate social interactions and territory defense.

Capybaras hold cultural importance in several South American societies. In Venezuela, they are traditionally hunted during Lent, as the Catholic Church historically classified them as 'fish,' permitting their consumption when red meat was forbidden. Their hides are used for leather, and their fat is rendered for medicinal and cosmetic purposes. In popular culture, capybaras are celebrated for their docile nature and have become symbols of tranquility and sociability. They are increasingly featured in ecotourism and wildlife parks, and their image is used in folklore and children's literature across South America.

Recent research has focused on capybara social dynamics, vocal communication, and their role as ecosystem engineers in wetland environments. Studies have elucidated the complexity of their vocal repertoire, revealing context-specific calls for alarm, mating, and social cohesion. Genetic analyses have clarified population structure and gene flow across fragmented habitats. Capybaras are also recognized as important hosts for ticks and other ectoparasites, with implications for the transmission of zoonotic diseases such as Brazilian spotted fever (Rickettsia rickettsii). Ongoing research explores their adaptability to human-altered landscapes and their potential as model organisms for studying social behavior and digestive physiology in large herbivorous rodents.

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The Capybara is currently classified as Least Concern on the IUCN Red List.

While the capybara is listed as Least Concern by the IUCN due to its wide distribution and large populations, it faces localized threats from habitat loss, wetland drainage, and hunting for meat, hides, and grease. In some regions, capybaras are subject to intensive hunting pressure, especially during the dry season when they congregate near dwindling water sources. Agricultural expansion and water pollution also pose significant challenges. Despite these threats, capybara populations are resilient and can thrive in modified landscapes, including cattle ranches and agricultural fields, provided water bodies are present. Invasive populations have been reported in Florida and other non-native areas, raising concerns about ecosystem impacts.