Ah, guinea pigs. It’s thought that the Spanish Conquistadors brought the furry little rodents across the sea with them sometime during the 1500s, where they—according to previous common knowledge—frequently appeared on the plates of European aristocrats.
Analysis of the skeleton of the guinea pig, combined with chemical research on its bones and a look at Flemish paintings from this period which depict the animal, has led researchers to conclude that guinea pigs must have been domesticated at this time in Europe, and not necessarily only raised for food.
While it is still common today to raise guinea pigs for food in South America, and the pigs undoubtedly provided some occasional measure of sustenance for Europeans, there’s much more to suggest that they were cared for by both middle-class and upper-class Europeans as pets.
The skeleton of the guinea pig found in 2007 had no evidence of being processed as food, so researchers are quite confident that the creature was a part of the family—and therefore given its own little burial in the backyard.
Guinea pigs would have been considered “exotic” animals, due to their origins across the ocean. It’s actually rare to find guinea pig bones in the archaeological record, which is why their purpose in Europe during the 16th & 17th centuries has remained somewhat vague until this time.
It’s also worth noting that, because guinea pigs are rodents (which tend to have remarkable reproductive capabilities), it’s entirely possible that the whole situation of guinea pigs in Europe may have started with just two creatures being brought over as curiosities… and their presence, needless to say, “expanded” from there.