Guinea pigs may have been one of the most important food sources in ancient Peru since well before Inca times. Unfortunately, the small size of their bones and the modern tendency to toss them in open garbage heaps--where they are immediately and entirely consumed by dogs--may be an appropriate analogy to explain why guinea pigs seem to be dramatically underrepresented in archaeological bone assemblages. This makes it comparatively harder for archaeologists to pinpoint cavy domestication accurately both in space and time. In any event, Peruvian archaeologists contend that domestication of the guinea pig may have begun as early as 5000 BCE in the Altiplano region of southern Peru and Bolivia. It is in this region that wild cavy (Cavia tschudii) populations can still be found to this day. Investigations at Chavin de Huantar in the north-central highlands of Peru clearly documents cavy exploitation at least by 900 BCE. Quite early on, the guinea pig may have been exploited on the coastal plain as well, and historic statues depicting cavies are known from the Moche region of Peru's northern coast. In solid archaeological contexts, the Moche Valley first sees significant guinea pig exploitation by 200 BCE. Archaeological evidence of cavy exploitation and breeding on the coastal plain of Ecuador dates from at least 500 BCE.
After the Spanish entrada into the New World, the guinea pig soon found its way to the European continent, where it immediately became popular as a household pet. Queen Elizabeth I herself owned a pet cavy, which may have contributed to its popularity. The name "guinea pig" is of uncertain origin. "Guinea" might be a corruption of Guiana in South America, or it may refer to Guinea in West Africa, where the cavy could have passed through on its way to Europe with the slave trade. Or it possibly refers to the gold coin known as a guinea, which is often said to have been the price one paid for the friendly rodent that squeaks like a pig.

Source: Domestication