The "Guinea Pig's" scientific name is "Cavy Porcellus". Sometimes referred to as a "Cavy". Although "Porcellus" in Latin means "little pig", they are actually a member of the rodent family and not related to pigs at all. Nor are they from Guinea, which is a common misconception.
The guinea pigs we all know and love today have always been domesticated. History records guinea pigs being domesicated as early as thousands of years B. C. However they are close decendants of those that once lived in the wild. Today in South America you can still find some living in the wild. Some debate exists as to if these found in the wild today are the same as the ancestors of our domesicated breeds or domesticated animals that have become feral. Some breeds, like the "Skinny", were actually bred for a specific purpose and they just came into being in the 70's.
The guiness book of world records says the longest living guinea pig lived to be over 14 years of age. Typically guinea pigs live between 4-8 years.
Females are called "Sows", males are called "Boars", but their young are referred to a "Pups".
Guinea pigs are social. Often it's common for guinea pig owners to have two. Males or females can live together in the same cage, especially if they are introduced to each other at a young age. Groups consisting of one boar with multiple sows can live together well, provided they have enough space. They bond with one another and their humans as well.
Newborn guinea pig pups are born with hair, teeth and nails. They are able to be held within a few hours of birth. The mothers are only able to nurse two at a time but can have litters of up to eight, the average is three. The largest recorded litter will shock you...seventeen, yes, seventeen! Gestation lasts between 65-72 days approximately, it's not an exact science as it can be difficult to tell when a sow actually conceives.
A guinea pig's teeth never stop growing! Provide them with crunchy veggies or safe items to chew on to keep the teeth at the proper length. If they grow to long, it will inhibit the guinea pigs ability to eat.
Males (Boars) become sexually mature at three to five weeks and need to be weaned and seperated from their mother and female siblings at that time. Females (Sows) can become fertile very young but are not commonly bred before four months of age. Sows over the age of eight months should never be bred if they have not had a litter previously as complications can arise and they may not be able to deliver their pups. In the best interest of the sow, they should not have another litter after the age of three.