The guinea pig (Cavia porcellus), also known as the domestic guinea pig, cavy or domestic cavy ( ), is a species of rodent. It belongs to the genus Cavia, family Caviidae, and its closest wild relatives include the montane guinea pig. Domestic guinea pigs typically weigh between 700 and 1,200 g (1.5 and 2.6 lb) and measure between 20 and 25 cm (8 and 10 in) in length; most breeds have fur, and they have long front teeth that grow continuously, leading the animals to chew regularly to wear them down. They are social animals, and are skittish in response to noise or danger, evincing a freeze or flight strategy.
Guinea pigs have been raised by humans as a meat source, as pets, as laboratory test subjects, and for ceremonial use. When guinea pigs are kept by humans, studies indicate the importance of social housing, environmental enrichment (like hides and structures), constant access to hay, and adequate space for healthy stress levels and well-being. Veterinary guidance recommends keeping males and females separate when breeding is not intended.Laurie Hess, DVM, DABVP, "Description and Physical Characteristics of Guinea Pigs", Merck Veterinary Manual, October 2025
Originally, guinea pigs were domesticated as livestock for their meat, in the Andean region of South America, and they are still consumed there. In the Andes, guinea pigs are also used in folk medicine and in community religious ceremonies.
In Western society, the guinea pig has enjoyed widespread popularity as a pet since its introduction to Europe and North America by European traders in the 16th century. Their docile nature and friendly responsiveness to handling and feeding have continued to make guinea pigs a popular choice of household pets. Organizations devoted to the competitive breeding and exhibition of guinea pigs have been formed worldwide. Through artificial selection, many specialized breeds with varying coat colors and textures have been selected by breeders.
Animal testing on guinea pigs has been carried out since the 17th century. The animals were used so frequently as model organisms in the 19th and 20th centuries that the epithet guinea pig came into use to describe a human test subject. Since that time, they have largely been replaced in laboratory testing by other rodents, such as mice and rats. However, they are still used in research, primarily as models to study human medical conditions.
History
Cavia porcellus is not found naturally in the wild; it is likely descended from closely related species of cavies, such as C. aperea, C. fulgida, and C. tschudii. These closely related species are still commonly found in various regions of South America. Studies from 2007 to 2010 applying molecular markers, and morphometric studies on the skull and skeletal morphology of current and mummified animals revealed the ancestor to be most likely C. tschudii. Some species of cavy, identified in the 20th century as C. anolaimae and C. guianae, may be domestic guinea pigs that have become feral by reintroduction into the wild.
Regionally known as cuy (a Spanish word derived from the Quechua quwi), the guinea pig was first domesticated as early as 5000 BC for food by tribes in the Andean region of South America (the present-day southern part of Colombia, Ecuador, Peru, and Bolivia), some thousands of years after the domestication of the South American camelids. The Moche people of ancient Peru worshipped animals and often depicted the guinea pig in their art.Berrin, Katherine & Larco Museum. The Spirit of Ancient Peru: Treasures from the Museo Arqueológico Rafael Larco Herrera. New York: Thames & Hudson, 1997.
Early accounts from Spanish settlers state that guinea pigs were the preferred sacrificial animal of the Inca people native to Peru. These claims are supported by archaeological digs and transcribed Quechua mythology, providing evidence that sacrificial rituals involving guinea pigs served many purposes in society such as appeasing the gods, accompanying the dead, or reading the future.
From about 1200 to the Spanish conquest in 1532, the indigenous people used selective breeding to develop many varieties of domestic guinea pigs, forming the basis for some modern domestic breeds. They continue to be a food source in the region; many households in the Andean highlands raise the animal.
In the early 1500s, Spanish, Dutch, and English traders took guinea pigs to Europe, where they quickly became popular as exotic pets among the upper classes and royalty, including Queen Elizabeth I. The earliest known written account of the guinea pig dates from 1547, in a description of the animal from Santo Domingo. Because cavies are not native to Hispaniola, the animal was believed to have been earlier introduced there by Spanish travelers. Zooarchaeological evidence indicates South American ceramic-making migrants likely introduced guinea pigs to the West Indies around 500 BC.Newsom and Wing, 2004, cited in It was present in the Ostionoid period on Puerto Rico, for example, long before the advent of the Spaniards.deFranca, S.D., Hadden, C.S., LeFebvre, M.J. and DuChemin, G. 2010. "Animal use at the Tibes Ceremonial Center." In: Curet, A. and Stringer, L.M. (eds.). Tibes: People, power, and ritual at the center of the cosmos. The University of Alabama Press, Tuscaloosa, Alabama, USA. pp. 115–151.
The guinea pig was first described in the West in 1554 by the Swiss naturalist Conrad Gessner. Its binomial scientific name was first used by Erxleben in 1777; it is an amalgam of Pallas' generic designation (1766) and Linnaeus' specific conferral (1758).
The earliest-known European illustration of a domestic guinea pig is a painting (artist unknown) in the collection of the National Portrait Gallery in London, dated to 1580, which shows a girl in a typical Elizabethan dress holding a tortoise-shell guinea pig in her hands. She is flanked by her two brothers, one of whom holds a pet bird.Reported, with colour illustration, in The Daily Telegraph, London, 21 August 2013. The picture dates from the same period as the oldest recorded guinea pig remains in England, which are a partial cavy skeleton found at Hill Hall, an Elizabethan manor house in Essex, and dated to around 1575.
Nomenclature Breeders tend to use the name "cavy" or "domestic cavy" for the animal, but "guinea pig" is more commonly used in scientific and laboratory contexts.
Latin name The scientific name of the common species is Cavia porcellus, with being Latin for "little pig". Cavia is Neo-Latin; it is derived from cabiai, the animal's name in the language of the Galibi tribes once native to French Guiana. Cabiai may be an adaptation of the Portuguese (now ), which is itself derived from the Tupi word , meaning rat.
Guinea pig Despite their name, guinea pigs are not native to Guinea, nor are they closely related to pigs. The origin of "guinea" in "guinea pig" is unclear. One proposed explanation is that the animals were brought to Europe by way of Guinea, leading people to think they had originated there. "Guinea" was also frequently used in English to refer generally to any far-off, unknown country, so the name may be a colorful reference to the animal's exotic origins.
Another hypothesis suggests the "guinea" in the name is a corruption of "Guiana", an area in South America. A common misconception is that they were so named because they were sold for the price of a guinea coin. This hypothesis is untenable because the guinea was first struck in England in 1663, and William Harvey used the term "Ginny-pig" as early as 1653. Others believe "guinea" may be an alteration of the word coney (rabbit); guinea pigs were referred to as "pig coneys" in Edward Topsell's 1607 treatise on quadrupeds.
How the animals came to be called "pigs" is not clear. They are built somewhat like pigs, with large heads relative to their bodies, stout necks, and rounded rumps with no tail of any consequence; some of the sounds they emit are very similar to those made by pigs, and they spend a large amount of time eating. They can survive for long periods in small quarters, like a "pig pen", and were easily transported by ship to Europe.
Other languages Guinea pigs are called or in Quechua and or (plural cuyes, cuyos) in the Spanish of Ecuador, Peru, and Bolivia.
Many of the animal's names allude to pigs. The German word is , literally "little sea pig", apparently because they were brought to Germany from overseas. Similarly, in Polish they are called , in Hungarian , and in Russian ().
The French term is cochon d'Inde (Indian pig) or cobaye; the Dutch called it Guinees biggetje (Guinean piglet) or cavia (or in some dialects, ); and in Portuguese, it is variously referred to as cobaia, from the Tupi word, or as (little Indian pig). This association with pigs is not universal among European languages; for example, the common word in Spanish is conejillo de Indias (little rabbit of the Indies).
The Chinese refer to the animal as (túnshǔ, "pig mouse"), and sometimes as (hélánzhū, 'Netherlands pig') or (tiānzhúshǔ, "Indian mouse"). The Japanese word for guinea pig is (), which derives from the name of another mountain-dwelling rodent, the marmot. This word is how the guinea pigs were called by Dutch traders, who first brought them to Nagasaki in 1843. A less common Japanese word for guinea pig is 天竺鼠 (てんじくねずみ or ), which translates as "India rat".
Biology
Guinea pigs are relatively large for rodents. In pet breeds, adults typically weigh between and measure between in length. Some livestock breeds weigh when full grown. Pet breeds live an average of four to five years but may live as long as eight years. According to Guinness World Records, , the longest-lived guinea pig was 14 years, 10 months, and 2 weeks old. Most guinea pigs have fur, but one laboratory breed adopted by some pet owners, the skinny pig, is mostly furless. In contrast, several breeds have long fur, such as the Peruvian, the Silkie, and the Texel. They have four front teeth and small back teeth. Their front teeth grow continuously, so guinea pigs chew on materials such as wood to wear them down to prevent them from becoming too long. In the 1990s, a minority scientific opinion emerged proposing that caviomorphs such as guinea pigs, chinchillas, and degus are not actually rodents, and should be reclassified as a separate order of mammals (similar to the rodent-like lagomorphs which includes rabbits and hares). Subsequent research using wider sampling restored the consensus among mammalian biologists regarding the current classification of rodents, including guinea pigs, as monophyletic.
Wild cavies are found on grassy plains and occupy an ecological niche similar to that of cattle. They are social animals, living in the wild in small groups ("herds") that consist of several females ("sows"), a male ("boar"), and their young ("pups" not "piglets", a break with the preceding porcine nomenclature). Herds of animals move together, eating grass or other vegetation, yet do not store food. While they do not burrow themselves or build nests, they frequently seek shelter in the burrows of other animals, as well as in crevices and tunnels formed by vegetation. They are crepuscular and tend to be most active during dawn and dusk when it is harder for predators to spot them.