Taxonomy and History

This chapter describes the place that Guinea pigs (Cavia porcellus) occupy in research and also discusses its origins, genetic features, and inbred strains. Guinea pigs are rodents within the hystricomorpha suborder while the suborders sciuromorpha and myomorpha contain the other rodent species. This special place in research implies that guinea pigs are one of the most commonly used laboratory animals in research. After a peak of usage in the 1960s at an estimated 2.5 million guinea pigs per year, the number of guinea pigs used per year in biomedical research has steadily declined. Much of the decline in guinea pig usage in research stems from the growing use of genetically engineered mice and rats for specific disease models. Even with a decrease in their use in research, guinea pigs have continued to increase in popularity as pets. Their "small size, cleanliness, docileness, and relatively easy maintenance" appeal to pet owners who live in smaller living spaces more common in urbanized societies. Some major areas of current research involving guinea pigs include infectious diseases, allergenic assays that cannot be performed via the local nymph node assay method, mechanisms of hearing, reproductive toxicology, and the provision of blood meal sources for blood-feeding insects such as mosquitoes.