Capybaras are the world’s largest rodents. They resemble guinea pigs but are much larger. They have large, broad heads with short, rounded ears and eyes placed far back on the head. Their snout is heavy and blunt with a large upper lip and big nostrils. Their neck and legs are short. Adults weigh between 110 and 173.8 pounds (50 to 79 kilograms) and have a head and body length of 39.4 to 51.2 inches (100 to 130 centimeters).
Capybaras have four toes on their front legs and three on their back legs, all with short and strong claws. Their feet are partially webbed, making them good swimmers. Their front legs are shorter than the hind legs.
Their bodies are covered with short, coarse fur ranging in color from reddish brown to grey on the upper body and light yellow to brown on the lower body. Adult males have a bare, raised area at the top of their snouts that contains a scent gland that is used to mark their territories. The tail is short and not functional. Female capybaras are usually larger than males.
Capybaras are found on the eastern side of the Canal Zone in Panama, and on the east side of the Andes Mountains in South America, including Peru, Colombia, Venezuela, French Guiana, Guyana, Uruguay, Paraguay, Bolivia, Ecuador, Brazil, and northeastern Argentina.
Capybaras live in areas of dense trees and plants near rivers, streams, lakes, ponds, marshes, and swamps. There are four areas in South America where there are large concentrations of capybaras: the llanos (plains) in Venezuela, the Pantanal wetlands in western Brazil, the Taim lowlands in southern Brazil, and Marajó Island, at the mouth of the Amazon River in northeastern Brazil.
Capybaras are herbivores, meaning they are plant-eaters. Much of their time is spent grazing and foraging for food, which consists primarily of protein-rich grasses. An adult eats 6 to 8 pounds (2.7 to 3.6 kilograms) of grasses a day. They also eat water plants, fruits, and vegetables, including wild melons and squashes.
Since grasses are difficult for most mammals to digest, the capybara’s digestive system has adapted to make it easier. One of these adaptations is a large fermentation chamber in the intestines called the cecum (SEE-kum). Capybaras also engage in coprophagy (kuh-PRAH-fuh-gee), which means they eat some of their own feces. These softer feces are rich in nutrients.
BEHAVIOR AND REPRODUCTION
Capybaras are social, living in groups of six to twenty animals, although groups of one hundred or more have been reported. The group has a dominant male, several adult females, their offspring, and several submissive adult males. The group is usually composed of family members and outsiders are rarely accepted. There is a social hierarchy in the group as a whole and within female members. The dominant male aggressively and sometimes viciously enforces this hierarchy.
In the wild, capybaras are usually active in the early morning and twilight. During the heat of the day, they rest intermittently in shallow beds in the ground or shaded areas of shallow water. In areas where there are higher concentrations of people, the capybara has become nocturnal, meaning it is most active at night.
When a capybara becomes startled or alarmed on land, it will run with a gallop much like that of a horse. If it feels it is in immediate danger, it will seek safety in water where it can stay submerged for about five minutes. With its partially webbed feet, the capybara is an extremely capable swimmer and diver. It can swim while submerged or with its eyes, nostrils, and ears just above the water’s surface, much like a hippopotamus. It can also hide among water plants, with just its nostrils above the water line. Capybaras can make several vocal sounds, including a lowpitched clicking noise when it is content; long, sharp whistles; short grunts; and a purr to indicate submissiveness. When a capybara spots a predator or feels it is in imminent danger, it will bark. Nearby capybaras will stand motionless at alert. If the caller continues to bark, they will race into the nearest water and gather closely in a group, with their young in the center for protection.
Capybaras are somewhat territorial and the home territory of a herd or group averages about 200 acres (80 hectares). The size of the range varies, depending on the season. Home ranges of groups often overlap. A group tends to get larger during the dry season and smaller in the wet season when groups tend to break into smaller groups as more marshes and wetlands are available. There are core areas within a group’s range that it will protect for its exclusive use.
Mating occurs throughout the year but is highest in April and May. Females usually have one litter per year although two litters are not uncommon if conditions are favorable. The female gestation period, the time they carry their young in the womb, is 104 to 156 days. Litter size ranges from one to eight, with five being the average. Newborns can see soon after birth and can eat grass after one week. Young capybaras stay together in a group and females will allow infants other than their own to nurse. Both males and females reach puberty, the age of sexual maturity, at about fifteen months of age. The average lifespan in the wild is eight to ten years. In captivity, several capybaras have lived for more than twelve years.
Capybaras have several natural predators, animals that hunt them for food, in the wild, including jaguars, anacondas (large water snakes), and caiman (KAY-mun), a large reptile similar to alligators and crocodiles. Young capybaras are eaten by foxes, vultures, and wild dogs.
CAPYBARAS AND PEOPLE
Capybaras are hunted in the wild by humans for their meat and skin, which is used to make wallets and purses. They are also raised on ranches, much like cattle, for their commercial value. Their meat when cooked is said to taste similar to pork or chicken but with a slight fishy flavor. Its fat is used in the manufacture of pharmaceuticals (medicinal drugs). Capybaras are considered agricultural pests in some areas because they raid crops of fruits, vegetables, and sugar cane.
The capybara is not currently threatened, according to the IUCN. Hunting and exterminations by humans have caused populations to decline in some areas, particularly Venezuela and Peru, while they remain stable in others. However, some conservationists say the overall numbers are in decline.