Guinea pig is the common name for the Cavy.� Cavy is short for the species name Cavia Porcellus.� Under the family name of Caviidae, guinea pigs are described as South American rodents with no visible tail, a single pair of mammae, four toes on each front foot, and three toes on each back foot.� The Guinea pig neither comes from Guinea nor is a pig.� The most accepted explanation for the name is that the animals grunt and squeal like a pig and were sold by British sailors in the 1600's for a guinea, an old English coin.� Guinea Pigs weigh from 2 to 4 pounds and with good care can live 8 to 10 years. Guinea pigs are herbivorous, meaning they eat only grasses, vegetables and fruit.� They are sociable animals so it is best they do not live alone. They do very well in pairs and trios.