Guinea pigs are the third most popular small animal pet but among the most poorly understood in terms of their social and environmental needs.
Guinea pigs kept alone experience genuine social deprivation — they are an obligately social species that has evolved to live in groups of 5-10 individuals and rely on conspecific contact for threat assessment, comfort and play. Switzerland's legal requirement for guinea pig companionship reflects this reality. Housing guinea pigs in small cages on inadequate diets — common in the pet trade — produces animals suffering from social isolation, exercise restriction and dental disease simultaneously. High-welfare guinea pig keeping requires at minimum: a same-species companion, adequate space, ad libitum hay, and regular health monitoring.