The domestic guinea pig has a wild ancestor, Cavia porcellus, which was thought to be the Restless Cavy, Cavia cutleri.
These restless cavies, lived in extended families in runs made through long grass which are protected by overhanging stems.

         Guinea Pigs were introduced to Britain in the early sixteenth century. They were very rare and were bought for about a guinea. Anything that was priced in guineas was considered being very valuable.
As with most pets the domestication history was never recorded. It was thought that the South American Indians kept and bred them as a source of meat as long ago as 3000 BC. When the Spaniards arrived in Peru in the sixteenth century they were the first Europeans to see the Guinea Pigs. After the Spanish conquest of the Inca Empire, Dutch merchants bought them back to Europe. They became very popular as pets among the rich and famous as Queen Elizabeth I kept one as a pet. Over the next 300 years, Europeans began breeding Guinea Pigs for different traits. In the nineteenth century, British immigrants bought some of these specially bred Guinea Pigs to America and other countries and the cavy fancy had began to flourish.

         Guinea Pigs are happiest at temperatures of 64-68 f. They cannot tolerate rapid fluctuations in temperature. They are found in a range of habitats, from grassy lowlands to levels of up to 4500 m in the mountains of the Andes, so they can tolerate quite low temperatures. They make their homes mainly on grassy plains, at the edges of forests and in marshes and rocky areas. They dig burrows in soil or among rocks and stay there during the day, and also sometimes take over burrows abandoned by other animals.

         Guinea pigs are very timid animals jumping to attention at any slight movement, but this behaviour is an excellent defense mechanism towards any predators. They are very agile so they can flee from them quickly.
They tend to live in groups of 10 but form large colonies in particularly suitable areas.

         There is always a dominant male in these colonies who has fought his way up to become the leader. Conflicts rarely occur between different colonies, if they do they are usually over food or territorial boundaries. But they do occur within the same colony; usually young males challenge the dominant one to take his place. Sometimes they will fight to the death if a huge problem has come about.

         Females become sexually mature at 4-5 weeks of age and the males at 8-10 weeks. Female guinea pigs come into Oestrus every two weeks for a duration of approximately 15 hours. They usually have a litter size of about 2-4 on average, who are weaned for at least 21-28 days ready for breeding.
They normally retire from breeding at two years of age, but during this time they would have had at least 8 litters with successful breeding.
Their usual life expectancy in the wild is substantially less than in captivity, which is 4-7 years due to predators and they wouldnt have the veterinary care.
         Their diet in the wild consists of grasses, leaves and berries.
In captivity they are fed on a balanced dried food diet which includes cooked flaked barley, cooked flake maize, wheat, oats, locust beans, dried grass and linseed.

         Guinea pigs are among a minority of animals who must obtain vitamin C in order for their digestive system to function properly. This is usually given through oranges or carrots.