Guinea pigs are native to South America and were first put into use by human society in what is now Boliva and Peru near the mountain range known as the Andes. Guinea pigs have historically been used as a source of food, as aides in religious ceremonies meant to detect and extract illnesses and as pets kept in the household.
Guinea pigs in the wild tend to live where there is cover to keep them safe from predators and to give them shelter to raise their young. They forage in clans or family units of 10 or so guineas, feeding on grass and other native plants.
Guinea pigs are not aggressive and are noted for their calm acceptance of human touch. This is most likely a trait bred into the guineas over time, though they have been popular pets in civilizations all over the world for hundreds of years since their domestication in Peru and Bolivia.
It was traditional in the areas where guinea pigs were first domesticated to give them as gifts rather than to offer them in trade or for sale. Guinea pigs were presented on special occasions as gifts from one family to another and were especially popular as gifts to give to children.