The Guinea pig (also commonly called the cavy after its scientific name) is a species of rodent belonging to the family Caviidae and the genus Cavia. Despite their common name, these animals are not pigs, nor do they come from Guinea. They are native to the Andes, and while no longer extant in the wild, they are closely related to several species that are commonly found in the grassy plains and plateaus of the region. The guinea pig plays an important role in the folk culture of many indigenous South American groups, especially as a food source, but also in folk medicine and in community religious ceremonies. Since the 1960s, efforts have been made to increase consumption of the animal outside South America.In Western societies, the guinea pig has enjoyed widespread popularity as a household pet since its introduction by European traders in the 16th century. Their docile nature, their responsiveness to handling and feeding, and the relative ease of caring for them, continue to make the guinea pig a popular pet. Organizations devoted to competitive breeding of guinea pigs have been formed worldwide, and many specialized breeds of guinea pig, with varying coat colors and compositions, are cultivated by breeders.Guinea pig is also used as a metaphor in English for a subject of experimentation; this usage became common in the first half of the 20th century. Biological experimentation on guinea pigs has been carried out since the 17th century; the animals were frequently used as a model organism in the 19th and 20th centuries, but have since been largely replaced by other rodents such as mice and rats. They are still used in research, primarily as models for human medical conditions such as juvenile diabetes, tuberculosis, scurvy, and pregnancy complications.