Hydrochoerus hydrochaeris
capybara

Hydrochoerus hydrochaeris is a strictly South American rodent species. Its range extends throughout most of Brazil, Uruguay, Venezuela, and Columbia, south into the Argentinian pampas, and west to the Andes. ("Capybara", 2001; "Capybara", 2002; "Capybara", 2009)

Capybaras are found only in areas where water is easily accessible: flooded grasslands are a favored habitat, as are marsh edges and lowland forests where grazing is good and there is water year-round. However, they occupy a range of habitats, including dry forest, scrub, and grasslands throughout South America. ("Capybara", 2001; "Capybara", 2009; Dunston and Gorman, 1998; Wolff and Sherman, 2007)

Capybaras are the largest of rodents, weighing from 35 to 66 kg and standing up to 0.6 meters at the shoulder, with a length of about 1.2 meters. Females of this species are slightly larger than males. Their fur is coarse and thin, and is reddish brown over most of the body, turning yellowish brown on the belly and sometimes black on the face. The body is barrel-shaped, sturdy, and tailless. The front legs are slightly shorter than the hind legs, and the feet are partially webbed. This, in addition to the location of the eyes, ears, and nostrils on top of the head, make capybaras well-suited to semi-aquatic life. ("Capybara", 2001; "Capybara", 2002; "Capybara", 2009; Dunston and Gorman, 1998; Wolff and Sherman, 2007)

Capybaras are polygynous to promiscuous. Dominant males in social groups try to monopolize mating activity, but this can be nearly impossible, especially in larger groups. Little research has been done on female mate choice in capybaras, but females have been observed mating with both dominant and subordinate males. ("Capybara", 2002; Herrera and Macdonald, 1993)

Capybaras breed throughout the year, with a peak in breeding activity at the beginning of the rainy season. When a female comes into estrus, a male will begin to follow her closely, sometimes for long periods of time, before mating occurs. During this time, the male is often driven off by a more dominant male, who then takes his place. Copulation occurs in the water and typically lasts only a few seconds, but a female usually copulates several times per estrus period. Young are born after 150 days, in litters ranging in size from 2 to 8.The young are precocial, beginning to stand and walk shortly after birth, and can graze within a week of being born. They are weaned at about 3 months old, during which time they suckle both from their own mother and the other females in the group, who are usually closely related. ("Capybara", 2001; "Capybara", 2002; "Capybara", 2009; Dunston and Gorman, 1998; Herrera and Macdonald, 1993; Ojasti, 1968; Wolff and Sherman, 2007)

Young capybaras stay with their parents' group until they are about a year old. They nurse for the first three months of this time. Both before and after weaning, the young move around together in a creche, and some of the work of parenting (such as suckling and watching for danger) is shared among all adults in the group. During much of their first year of life, the young are small, slow, and easily tired, making them especially vulnerable to predators. The protection of their natal group is essential to staying alive. Little is known about individual parental care in capybaras, but it seems that, because of the precocial state of the young and the system of cooperative parenting, the time and resources spent by each parent after birth are minimal. ("Capybara", 2002; "Capybara", 2009; Wolff and Sherman, 2007)

Capybaras live about 6 years on average (and as many as 10 years) in the wild and up to 12 years in captivity. ("Capybara", 2001; "Capybara", 2002)

Capybaras live in groups of around 10 adults of both sexes, although groups can range in size from 3 to 30 and larger aggregations often form around water resources during the dry season. Each group maintains and defends a territory that encompasses feeding and wallowing sites. Among males, there is a strict dominance hierarchy enforced by chasing and, rarely, fights. Group living appears to be extremely important to capybara survival—without a group, an individual is excluded from most grazing habitat and has no chance of finding a mate, so solitary capybaras are seldom found. Capybara society is relatively stable over the course of time: group membership changes rarely and a territory can be maintained by one group for over 3 years. Because of their large body size, capybaras are susceptible to heat stress. Activity is primarily crepuscular and the hottest part of the day is spent in the water. Capybaras are strong swimmers, helped by the fact that their bodies are only slightly denser than water. They seem to be just as at home in the water as on land. ("Capybara", 2001; "Capybara", 2002; Dunston and Gorman, 1998; Herrera and Macdonald, 1989; Herrera and Macdonald, 1993; Maldonado-Chaparro and Blumstein, 2008; Wolff and Sherman, 2007)

No information was found on home range sizes in capybaras.

Vocalization appears to be very important in capybara groups, but the purpose of many of the sounds made is unknown. However, young vocalize almost constantly and vocal communication among adults is also common. Individuals bark to warn the group of danger, this often results in the whole group rushing into the relative safety of the water. Scent is also important, especially in mating and establishing dominance. Male capybaras have a bare lump on the top of the snout, known as the morillo gland, which secretes a white liquid. The scent of this liquid acts as an olfactory “fingerprint”, signaling the status of the individual. It is rubbed on trees or shrubs to mark territory, or smeared on the male’s body to advertise his status and willingness to mate. Both males and females have two glands on either side of the anus. The combination of chemicals in the liquid they secrete is also highly individualized and seems to be used to recognize group members and mark territory. ("Capybara", 2001; "Capybara", 2002; Herrera and Macdonald, 1993; Maldonado-Chaparro and Blumstein, 2008)

Capybaras are grazers, feeding mainly on grasses and aquatic plants. Bark and fruit are consumed occasionally. They are also cophrophagous and spend part of each morning re-ingesting the previous day’s food. ("Capybara", 2002; Dunston and Gorman, 1998; Herrera and Macdonald, 1989)

Especially while young, capybaras are an important food source for many large predators, including anacondas, caimans, jaguars, and humans. While grazing, they are constantly on the lookout for predators and give an alarm bark when one is spotted. They often hide in the water, with just their nostrils and eyes exposed, and can stay completely submerged for up to five minutes. ("Capybara", 2001; "Capybara", 2009; Herrera and Macdonald, 1989; Wolff and Sherman, 2007)

In many parts of South America capybaras are the only large grazing species and can have a dramatic effect on the vegetation in an area. They are also mutualists or commensals with several types of birds which pick parasitic insects out of capybara fur or follow grazing capybaras and eat the insects they stir up from the grass. In addition, they are an important prey species for many different animals, as mentioned above. ("Capybara", 2001; "Capybara", 2009; Dunston and Gorman, 1998; Herrera and Macdonald, 1989; Tomazzoni, et al., 2005; Wolff and Sherman, 2007)

Capybaras are hunted for their meat and leather, both of which are said to be very high-quality. Capybara meat is especially popular during Lent, the 40-day period prior to Easter, because it is approved by the Catholic church as an alternative to beef or pork. (Presumably, the semiaquatic habit of the capybara convinced early priests that it was similar to fish.) Large-scale ranching of capybaras has been proposed to curtail illegal hunting and the animals have proved easy to domesticate, at least in small numbers. In fact, capybaras are more efficient grazers than cattle or other introduced livestock and are already an important source of food for many local people. ("Capybara", 2001; "Capybara", 2002; Grant, 2009)

Capybaras sometimes raid gardens or farms in search of food, such as melons, squashes, or grains. It has also been hypothesized that they are carriers of certain livestock diseases. ("Capybara", 2001; Maldonado-Chaparro and Blumstein, 2008)

The IUCN lists capybaras as a species of least concern, citing its large population, large distribution, and frequent occurrence within protected areas. However, some local populations are in decline due to over-hunting. ("Capybara", 2001; "IUCN Red List", 2008; Grant, 2009)