Guinea Pig

Guinea Pig, common name for certain small rodents with short, rounded ears and no tails. They have small, stout bodies, about 20 to 40 cm (about 8 to 16 in) long. The hair in some species is long and varies in texture from rough to smooth. Some guinea pigs are solidly white, black, or tawny; others are white, streaked, or blotched with darker colors. Guinea pigs are domesticated cavies, but in popular usage the term is applied to all species of cavies, domesticated or wild. Wild guinea pigs are native to South America. Among the most important species are those native to the higher ranges of the Andes and Peru, and a species found in domestication from Venezuela to Chile. Wild guinea pigs live in burrows, and also occasionally in dense vegetation. Their diet consists of vegetation. Most wild guinea pigs breed once a year, although one species breeds continually throughout the year under good conditions. They usually produce litters of two to four young, which are born in an advanced state of development and are able to feed themselves by nibbling foliage the day after birth.

Some authorities believe the domestic guinea pig was developed from the Peruvian animal. Domestic guinea pigs resemble wild guinea pigs in the rapidity of their early maturity. They develop so quickly during gestation that they shed their lacteal teeth in the womb and are born with their definitive teeth in place. Domesticated guinea pigs begin to breed at the age of two months. They breed a maximum of five times a year, and the litters contain an average of 4 animals, with a recorded extreme of 13 animals.

Guinea pigs have been valuable as experimental laboratory animals, especially in bacteriology for research on the effects of pathogenic microorganisms. They have been largely replaced in the laboratory by smaller animals, such as mice, rats, and hamsters. Guinea pigs are useful in diagnostic tests for tuberculosis, however, because of their low resistance to the tubercle bacillus, which kills them in four to eight weeks.

The origin of the term guinea pig is an unsolved etymological problem. Some authorities believe the name may come from Guineamen, who were in the slave trade and may have been the first to bring the animals from South America to England. Others believe guinea is a corruption of the word coney, because guinea pigs were called pig coneys in 1607.

Scientific classification: Guinea pigs belong to the family Caviidae. The guinea pig found in the Andes and Peru is classified as Cavia tschudii, and the domesticated guinea pig found from Venezuela to Chile as Cavia porcellus.