The capybara (Hydrochoerus hydrochaeris) is the world’s largest living rodent, native to the savannas and dense forests of South America. These animals are known for their calm, placid demeanor, often appearing unbothered by other species. Capybaras are a highly social species, rarely seen alone, and exhibit complex group behaviors central to their survival in semi-aquatic habitats.
The Collective Noun
A group of capybaras is most commonly referred to as a herd. This collective noun is used because capybaras are large, grazing mammals that move and feed together in open areas, similar to cattle or deer. Some sources also use the simpler, though less specific, terms group or troup to describe their gatherings. The use of “herd” reflects the capybara’s behavior as a terrestrial herbivore, despite its semi-aquatic nature. There is no single, officially recognized term of venery for capybaras, making “herd” the primary and most descriptive term for their large, cohesive gatherings.
Social Structure and Group Roles
Capybara herds are stable, structured social units with a distinct hierarchy. A typical group averages between 10 and 20 individuals, generally consisting of one dominant male, several adult females, and their offspring. The dominant male defends the group’s territory and aggressively enforces a linear dominance hierarchy, particularly among other males.
The main benefit of this grouping is defense against predators like jaguars, caimans, and anacondas. When danger is sensed, a capybara gives a short, sharp bark, signaling the entire herd to retreat quickly into the nearest body of water. Communication also involves various whistles, purrs, and grunts used to express emotions or establish social boundaries.
Females engage in cooperative parenting, known as alloparental care, which significantly increases the survival rate of the young. Adult females communally nurse pups, including those that are not their own, ensuring all young receive nourishment and protection. Subordinate males remain on the periphery of the group, often assisting with vigilance and protection, though the dominant male secures the majority of matings.
Environmental Influences on Group Size
The size of a capybara herd is influenced by the availability of water, as they are semi-aquatic and rely on aquatic habitats for thermoregulation and safety. During the wet season, when water and grazing resources are plentiful and widely distributed, herds tend to be smaller and more spread out. Group sizes during this period often remain closer to the average of 10 to 20 individuals, as resources can support smaller family units.
The dynamics change during the dry season, a time of resource scarcity and limited access to water sources. Capybaras are forced to congregate around the few remaining ponds, rivers, or streams, leading to the formation of much larger temporary “super-groups.” These aggregated herds can swell to 50 or even 100 individuals, all clustered near the limited aquatic refuges. This environmental pressure supersedes the internal social structure, temporarily increasing group size as a survival strategy against dehydration and increased predation risk.