As you might have guessed, guinea pigs are not beloved pets in Peru. Instead they are a traditional and important source of protein in the Andes, where they are known as cuy ("coo-ee"). Cuy is typically served fried or roasted, with rice and corn on the side.
Eating cuy is such a tradition (an estimated 65 million guinea pigs are consumed annually in Peru) that there are festivals celebrating the humble beast, with contests for the best dressed, largest, and of course best-tasting guinea pig. You can see a video about one such festival here (beware - the video might be disturbing to vegetarians and guinea pig pet owners). Eating cuy dates back to pre-colonial times. In fact, a famous religious painting in the cathedral in Cusco shows Jesus and his disciples sharing a big platter of cuy.