The Raising and Care of Guinea Pigs. With sections on - Varieties; Uses of Guinea Pigs; Food and Feeding; Housing; Breeding; Exhibiting; Selling and Shipping; Diseases; Profits in Cavy Raising. The Guinea Pig or Cavy belongs to the rabbit family and is a native of South America. Why they are called Guinea Pigs, one seems to kw, unless their shape suggests a small pig and the name Guinea is a corruption of Guiana, a country in South America. In size, shape and texture of fur they resemble a squirrel or rabbit. They have large bodies, short legs, small feet, tails and a wide range of colors. A full grown Cavy weighs between two and three pounds, which weight it attains at about 18 months of age. The males are usually larger than the females. When white people first visited the Andean region of South America they found the Cavy domesticated and living in the houses of the Indians, by whom they were used for food. They were introduced into Europe in the 16th Century and since that time have spread all over the world.