have these animals been domesticated?
Yes, domesticated animals generally live in cages, although some owners of large numbers of guinea pigs dedicate entire rooms to their pets.
Guinea pig
Domestic guinea pigs generally live in cages, although some owners of large numbers of guinea pigs dedicate entire rooms to their pets. 
where does the name guinea pig come from From Latin for "little pig"; derived from "cabiai", the animal's name in the language of the Galibi tribes once native to French Guiana what is their role in research and science? Italian biologists Marcello Malpighi and Carlo Fracassati conducted vivisections of this animal in their examinations of anatomic structures.
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Guinea pig [SEP] Domestic habitat
Activity is scattered randomly throughout the day; aside from an avoidance of intense light, no regular circadian patterns are apparent. Domestic guinea pigs generally live in cages, although some owners of large numbers of guinea pigs dedicate entire rooms to their pets. Cages with solid or wire mesh floors are used, although wire mesh floors can cause injury and may be associated with an infection commonly known as bumblefoot (ulcerative pododermatitis). "Cubes and Coroplast" (C&C) style cages are now a common choice. Cages are often lined with wood shavings or a similar material. Bedding made from red cedar (Eastern or Western) and pine, both softwoods, were commonly used in the past, but these materials are now believed to contain harmful phenols (aromatic hydrocarbons) and oils.