The genus Hydrochoerus contains two living species of capybaras from South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

 and Panama

Panama

Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...

, the largest living rodents in the world. The genus name is derived from the Greek

Greek language

Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 ὕδωρ (hýdor, water) plus χοίρος (choíros, pig).

Characteristics

Capybara are semiaquatic, found in and near lakes, rivers, swamps and flooded savanna. Their diet is dominated by grasses. Adults weigh up to 65 kg (140 lb). The gestation period

Gestation period

For mammals the gestation period is the time in which a fetus develops, beginning with fertilization and ending at birth. The duration of this period varies between species.-Duration:...

 is 130–150 days, with 2–8 (most commonly 4) young born to females.

Behavior

Capybara are highly social, living in groups of up to 100 and communicating through a variety of vocalizations (Rowe and Honeycutt, 2003). Breeding is polygynous

Polygyny

Polygyny is a form of marriage in which a man has two or more wives at the same time. In countries where the practice is illegal, the man is referred to as a bigamist or a polygamist...

, with males forming harem

Harem

Harem refers to the sphere of women in what is usually a polygynous household and their enclosed quarters which are forbidden to men...

s.

Classification

Molecular

Molecular phylogeny

Molecular phylogenetics is the analysis of hereditary molecular differences, mainly in DNA sequences, to gain information on an organism's evolutionary relationships. The result of a molecular phylogenetic analysis is expressed in a phylogenetic tree...

 results have consistently suggested that Hydrochoerus is most closely related to Kerodon

Kerodon

The genus Kerodon contains two species of South American rock cavies related to capybaras.-Characteristics:Adults weigh about 800 grams. Gestation period is 76–77 days with 1-3 young born to females. Metabolic rate is 0.45 ml-O2/...

 (the rock cavies), and that the two evolved from within the Caviidae

Caviidae

The cavy family is a family of rodents native to South America, and including the domestic guinea pig, wild cavies, and the capybara, among other animals...

. This led Woods and Kilpatrick to unite the two into the subfamily Hydrochoerinae

Hydrochoerinae

Hydrochoerinae is a subfamily of Caviidae, consisting of two living genera, Hydrochoerus, the capybaras, and Kerodon, the rock cavies. In addition, a number of extinct genera related to capybaras should also be placed in this subfamily...

 within Caviidae. Based on use of a molecular clock

Molecular clock

The molecular clock is a technique in molecular evolution that uses fossil constraints and rates of molecular change to deduce the time in geologic history when two species or other taxa diverged. It is used to estimate the time of occurrence of events called speciation or radiation...

 approach, Hydrochoerus appears to have diverged from Kerodon in the late Middle Miocene

Miocene

The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...

.

Species

• Genus Hydrochoerus
  • Hydrochoerus gaylordi (extinct)
  • Hydrochoerus hydrochaeris - capybara
  • Hydrochoerus isthmius - lesser capybara