The guinea pig or domestic guinea pig (Cavia porcellus), also known as cavy or domestic cavy, is a species of rodent belonging to the family 'Caviidae' and the genus 'Cavia'. Despite their common name, guinea pigs are not native to Guinea, nor are they biologically related to pigs, and the origin of the name is still unclear. They originated in the Andes of South America, and studies based on biochemistry and hybridization suggest they are domesticated descendants of a closely related species of cavy such as 'C. tschudii', and therefore do not exist naturally in the wild.

In Western society, the domestic guinea pig has enjoyed widespread popularity as a pocket pet, a type of household pet, since its introduction by European traders in the 16th century. Their docile nature, friendly responsiveness to handling and feeding, and the relative ease of caring for them have made and continue to make guinea pigs a popular choice of pet. Organizations devoted to the competitive breeding of guinea pigs have been formed worldwide, and many specialized breeds with varying coat colors and textures are selected by breeders.

More Info: en.wikipedia.org