Guinea pigs are highly social animals whose welfare is fundamentally compromised by solitary housing, yet single-animal keeping remains common among pet owners.
Guinea pigs are frequently sold and kept as single animals, which represents a fundamental welfare failure for a species that is biologically and psychologically dependent on conspecific company. Solitary guinea pigs may appear calm or content, but research consistently shows elevated stress markers and reduced welfare compared to socially housed animals. The Five Freedoms and Five Domains frameworks both identify the freedom to express normal behaviour — including social behaviour — as a welfare requirement. Switzerland recognised this by legislating for social housing of guinea pigs. Pet owners, retailers, and welfare organisations in other countries should advocate for equivalent standards. Bonded pairs or compatible groups are the minimum for adequate welfare.