Capybara

About the capybara

The capybara is the largest living rodent on Earth, native to every country in South America except Chile. Its name comes from the Tupi word ka'apiûara, roughly "one who eats slender leaves," and it belongs to the genus Hydrochoerus alongside the lesser capybara; its closer relatives include guinea pigs and rock cavies, with more distant ties to the agouti, chinchilla, and nutria. Molecular studies since 2002 have placed the genus in the same subfamily as the rock cavies, within the larger family Caviidae.

A capybara has a heavy, barrel-shaped body and a broad, blunt-muzzled head, with reddish-brown fur on top that fades to yellowish-brown underneath. Its coat is coarse, 1.2 to 4.7 inches (30–120 mm) long, and lacks the fine underhair found in many other rodents. Adults measure 3.5 to 4.4 feet (106–134 cm) long and stand 20 to 24 inches (50–62 cm) tall at the withers, typically weighing 77 to 146 pounds (35–66 kg), with females running slightly heavier than males; the largest wild individuals on record reached 201 pounds (91 kg) in Brazil and 162 pounds (73.5 kg) in Uruguay. Its feet are slightly webbed, with four toes on the front feet and three on the hind feet, and its tail is vestigial. The eyes, ears, and nostrils sit near the top of the head — a useful arrangement for an animal that spends much of its life partly submerged.

In the wild, capybaras live near freshwater rivers, lakes, ponds, streams, swamps, and reservoirs, favoring seasonally flooded savannas, wetlands, and gallery forests, and they have adapted well to cattle ranches. They stay mostly at low elevations, though they've been recorded as high as 4,900 feet (1,500 m) in Brazil's Chapada dos Veadeiros National Park. Escaped or released capybaras have also established themselves outside their native range; sightings are fairly common in Florida, and one was spotted on California's Central Coast in 2011, occupying territory where prehistoric relatives once lived during the Pleistocene.

Behavior and diet

Capybaras are gregarious animals, usually living in groups of 10 to 20 that include a few adult males, several adult females, and their young, though groups can swell to 50 or even 100 individuals in the dry season when animals concentrate around remaining water sources. They are excellent swimmers, able to hold their breath underwater for up to five minutes, and follow a daily rhythm of resting on land in the morning, cooling off in water through the hot early afternoon, and grazing from late afternoon into the night. Home ranges typically span 12 to 40 acres (5–16 hectares) and include a mix of open water, grassland for grazing, and dry land for resting; most capybaras don't wander far, with the majority recaptured in one study within about 1,000 meters of where they were originally tagged.

The diet is almost entirely grasses and aquatic plants, supplemented with fruit and tree bark, and capybaras are selective feeders that will single out one plant species while ignoring others nearby. They eat their own droppings — a behavior called autocoprophagy — to reintroduce gut bacteria that help digest cellulose and extract more nutrients from tough plant material, and they also re-chew regurgitated food much like cattle chewing cud. Like guinea pigs, capybaras cannot synthesize their own vitamin C, and captive animals without a supplemented diet can develop gum disease from scurvy. In the wild, predators including jaguars, ocelots, cougars, caimans, eagles, and green anacondas keep most capybaras from living past four years, even though the species can live 8 to 10 years at maximum and up to 12 in captivity.

Reproduction centers on scent and vocal signaling. A female in estrus gives off a subtly different scent and whistles through her nose to draw nearby males, and mating itself happens only in water, where a female can simply submerge or leave if she doesn't want to mate with a particular male. Dominant males secure more matings individually, but subordinate males collectively account for more matings overall because a dominant male cannot guard every female in a large group. Gestation runs 130 to 150 days and produces an average litter of four young, with a possible range of one to eight; births happen on land, and newborns rejoin the group and can eat grass within a week, though they continue to nurse from any female in the group until weaned around 16 weeks. Capybaras communicate with barks, chirps, whistles, huffs, and purrs, and can make dog-like barks when threatened or when females are herding young.

Range and habitat

Capybaras are found across every South American country except Chile, always in close association with freshwater. Typical habitats include seasonally flooded savannas, wetlands, gallery forests along rivers in tropical rainforest, and the margins of lakes, streams, and reservoirs. The species has proven adaptable to human land use, thriving on cattle ranches, and escaped or released populations now turn up outside South America in similar wet habitats, including recurring sightings in Florida and at least one confirmed sighting on California's Central Coast.

Conservation status

The capybara is listed as Least Concern and its population remains stable across most of its South American range, though hunting has reduced numbers in some areas. It is hunted for meat and hide, and for grease rendered from its thick, fatty skin; in parts of Venezuela, capybara meat is traditionally eaten during Lent and Holy Week under a historical church dispensation. In some regions capybaras are farmed rather than hunted in the wild, which has the side effect of protecting the wetland habitats those farms depend on, and the species' ability to breed quickly has helped it withstand hunting pressure.