guinea pigs

plural of guinea pig

Any tailless rodent of the genus Cavia, which have short ears and superficially resemble large hamsters.
(especially) Any tailless rodent of the genus Cavia, which have short ears and superficially resemble large hamsters.
(figuratively) A living experimental subject.
(dated, slang) A professional company director, without time or real qualifications for the duties.
(obsolete) A midshipman in the East India service; (by extension) a low-skilled or non-proficient seaman.