The Guinea pig (also commonly called the cavy) is a species of rodent belonging to the family Caviidae and the genus Cavia. Domesticated guinea pigs come in many breeds, which have been developed since their introduction to Europe and North America. These varieties vary in hair and color composition.
The most common varieties found in pet stores are the English shorthair. Like humans, but unlike most other mammals, guinea pigs cannot synthesize their own vitamin C and must obtain this vital nutrient from food. If guinea pigs do not ingest enough vitamin C, they can suffer from potentially fatal scurvy. Guinea pigs are prey animals whose survival instinct is to mask pain and signs of illness, and many times health problems may not be apparent until a condition is severe or in its advanced stages.
Guinea pigs benefit from feeding on fresh grass hay, such as timothy hay, in addition to food pellets which are often based from timothy. Alfalfa is also a popular food choice; most guinea pigs will eat large amounts of alfalfa when offered it.