Guinea Pig

Guinea pigs were domesticated by indigenous peoples in the Andean highlands of South America -- in what is now Peru, Bolivia, Ecuador, and southern Colombia -- with archaeological evidence pointing to domestication as early as 5000 BC. They were originally raised as a food source rather than as companions, a practice that continues in parts of the Andes today.

Selective breeding by Andean peoples produced multiple varieties well before European contact, with organized breeding efforts traceable from roughly 1200 AD up to the Spanish conquest of the region in 1532. Guinea pigs were later brought to Europe by traders, where they became popular first as curiosities and pets and eventually as laboratory animals.

In the wild, guinea pigs live in small social groups, typically several females and their offspring alongside one male. This herd instinct carries over into captivity: guinea pigs kept alone often show signs of stress or boredom that a companion can prevent, and most veterinary and welfare organizations recommend housing them in pairs or small groups rather than singly.

The preference for company is strong enough that some countries have written it into law. Switzerland and Sweden both restrict keeping a guinea pig entirely alone, treating solitary housing as a welfare concern rather than simply an owner's choice. Some Swiss owners even arrange short-term companion rentals if a paired guinea pig loses its cage-mate.