Guinea pig

The guinea pig (Cavia porcellus), also called the domestic cavy (pronounced KAY-vee), is a rodent in the genus Cavia and family Caviidae. Its closest wild relatives include the montane guinea pig. Domestic guinea pigs usually weigh between 700 and 1,200 grams (1.5 to 2.6 pounds) and measure 20 to 25 centimeters (8 to 10 inches) long. Most breeds have fur, and their long front teeth grow continuously, so they must chew regularly to keep them worn down. They are social animals that are skittish around noise or danger, responding with a freeze or flight strategy.

Humans have raised guinea pigs for meat, as pets, for laboratory testing, and in ceremonies. When kept by people, studies stress the need for social housing, environmental enrichment (such as hides and structures), constant access to hay, and enough space to maintain healthy stress levels and well-being. Veterinary advice recommends keeping males and females apart unless breeding is intended.

Originally domesticated as livestock for meat in the Andean region of South America, guinea pigs are still eaten there. In the Andes, they are also used in folk medicine and community religious ceremonies.

In Western society, guinea pigs became popular pets after European traders brought them to Europe and North America in the 16th century. Their docile nature and friendly response to handling and feeding have kept them a common household pet. Worldwide, organizations exist for competitive breeding and exhibition. Through artificial selection, breeders have developed many specialized breeds with different coat colors and textures.

Animal testing on guinea pigs began in the 17th century. They were used so often as model organisms in the 19th and 20th centuries that the term "guinea pig" came to mean a human test subject. Since then, they have largely been replaced in labs by other rodents like mice and rats, but they are still used in research, mainly as models for human medical conditions.

**History**

*Cavia porcellus* is not found in the wild; it likely descends from closely related cavy species such as *C. aperea*, *C. fulgida*, and *C. tschudii*. These relatives still live in various parts of South America. Studies from 2007 to 2010 using molecular markers and skull and skeletal morphology of current and mummified animals pointed to *C. tschudii* as the most likely ancestor. Some cavy species identified in the 20th century as *C. anolaimae* and *C. guianae* may be domestic guinea pigs that became feral after reintroduction to the wild.

Known regionally as *cuy* (from the Quechua *quwi*), the guinea pig was first domesticated for food around 5000 BC by tribes in the Andean region (present-day southern Colombia, Ecuador, Peru, and Bolivia), a few thousand years after the domestication of South American camelids. The Moche people of ancient Peru worshipped animals and often depicted guinea pigs in their art.

Early Spanish settlers reported that guinea pigs were the preferred sacrificial animal of the Inca people of Peru. Archaeological digs and transcribed Quechua mythology support this, showing that sacrificial rituals involving guinea pigs served purposes like appeasing gods, accompanying the dead, or reading the future.

From about 1200 until the Spanish conquest in 1532, indigenous people used selective breeding to develop many varieties of domestic guinea pigs, forming the basis for some modern breeds. They remain a food source in the region, and many households in the Andean highlands raise them.

In the early 1500s, Spanish, Dutch, and English traders brought guinea pigs to Europe, where they quickly became popular exotic pets among the upper classes and royalty, including Queen Elizabeth I. The earliest known written account of the guinea pig dates from 1547, describing the animal from Santo Domingo. Since cavies are not native to Hispaniola, it is believed Spanish travelers introduced them there earlier. Zooarchaeological evidence suggests South American ceramic-making migrants likely brought guinea pigs to the West Indies around 500 BC. For example, they were present in the Ostionoid period on Puerto Rico long before the Spaniards arrived.

The guinea pig was first described in the West in 1554 by Swiss naturalist Conrad Gessner. Its binomial scientific name was first used by Erxleben in 1777, combining Pallas' generic designation (1766) and Linnaeus' specific conferral (1758).

The earliest known European illustration of a domestic guinea pig is an anonymous painting from 1580 in the National Portrait Gallery in London, showing a girl in Elizabethan dress holding a tortoise-shell guinea pig, flanked by two brothers (one with a pet bird). This picture dates from the same period as the oldest recorded guinea pig remains in England: a partial skeleton found at Hill Hall, an Elizabethan manor in Essex, dated to around 1575.

**Nomenclature**

Breeders tend to call the animal a "cavy" or "domestic cavy," while "guinea pig" is more common in scientific and laboratory contexts.

**Latin name**

The scientific name of the common species is *Cavia porcellus*, where *porcellus* is Latin for "little pig." *Cavia* is Neo-Latin, derived from *cabiai*, the animal's name in the language of the Galibi tribes once native to French Guiana.