Guinea pig
A Guinea pig or Cavy is a large rodent native to the Andes Mountains. They were originally domesticated as a readily available food source, kept in homes and used as needed. They are usually friendly, and make excellent pets.
Recent research has been directed towards making larger, more appetizing guinea pigs.
Like humans, they need Vitamin C. If they do not get enough in their diet, they get scurvy.
Guinea pigs were one of the first animals to be used in medical experiments, to the point where their name became synonymous with "test subject". Lavoisier used them in metabolism studies using a bomb calorimeter.