[3] Its common name is derived from Tupi ka'apiûara, a complex agglutination of kaá (leaf) + píi (slender) + ú (eat) + ara (a suffix for agent nouns), meaning "one who eats slender leaves", or "grass-eater".

[4] The genus name, hydrochoerus, comes from Greek ὕδωρ (hydor "water") and χοῖρος (choiros "pig, hog") and the species name, hydrochaeris, comes from Greek ὕδωρ (hydor "water") and χαίρω (chairo "feel happy, enjoy").

[7] Since 2002, molecular phylogenetic studies have recognized a close relationship between Hydrochoerus and Kerodon, the rock cavies,[8] supporting placement of both genera in a subfamily of Caviidae.

[9][10] This is largely due to the recognition that capybara molar teeth show strong variation in shape over the life of an individual.

Its sweat glands can be found in the surface of the hairy portions of its skin, an unusual trait among rodents.

[23] Capybaras are herbivores, grazing mainly on grasses and aquatic plants,[14][24] as well as fruit and tree bark.

[27] Capybaras are autocoprophagous,[28] meaning they eat their own feces as a source of bacterial gut flora, to help digest the cellulose in the grass that forms their normal diet, and to extract the maximum protein and vitamins from their food.

[30] The maximum lifespan of the capybara is 8 to 10 years,[31] but in the wild capybaras usually do not live longer than four years because of predation from South American big cats such as jaguars and cougars and from non-mammalian predators such as harpy eagles, caimans, green anacondas and piranhas.

[33] Capybara groups can consist of as many as 50 or 100 individuals during the dry season[29][34] when the animals gather around available water sources.

A crystalline form of scent secretion is coated on these hairs and is released when in contact with objects such as plants.

Capybaras scent-mark by rubbing their morrillos on objects, or by walking over scrub and marking it with their anal glands.

As temperatures increase during the day, they wallow in water and then graze during the late afternoon and early evening.

[39] Capybaras are not considered a threatened species;[1] their population is stable throughout most of their South American range, though in some areas hunting has reduced their numbers.

[14][19] Capybaras are hunted for their meat and pelts in some areas,[40] and otherwise killed by humans who see their grazing as competition for livestock.

They can be found in many areas in zoos and parks,[27] and may live for 12 years in captivity, more than double their wild lifespan.

[19] Capybaras are docile and usually allow humans to pet and hand-feed them, but physical contact is normally discouraged, as their ticks can be vectors to Rocky Mountain spotted fever.

[41] The European Association of Zoos and Aquaria asked Drusillas Park in Alfriston, Sussex, England, to keep the studbook for capybaras, to monitor captive populations in Europe.

This inspired social media users to jokingly adopt the capybara as a symbol of class struggle and communism.

[48][49] Brazilian Lyme-like borreliosis likely involves capybaras as reservoirs and Amblyomma and Rhipicephalus ticks as vectors.

[51] The capybaras have influenced an anime character named Kapibara-san, and a series of merchandise such as plush toys.

[citation needed] A common meme format includes capybaras in various situations with the song "After Party" by Don Toliver.

[55][better source needed] Capybaras are also associated with the phrase "Ok I pull up", the opening lyric in Toliver's song.