Rabbits and guinea pigs are highly social species that require appropriate companionship for good welfare, and solitary housing is a primary welfare failure in these commonly kept pets.
The welfare case for same-species companionship in rabbits and guinea pigs is overwhelming. Guinea pigs in particular show severe welfare deterioration when kept alone, including repetitive behaviour, reduced immunity, and shortened lifespan. Bonded rabbit pairs show reduced stress indicators and engage in social grooming and resting that reflects genuine psychological wellbeing. The primary welfare challenge is safe bonding of compatible animals; rescue organisations often provide bonding services that match suitable companions. Never house different small animal species together as companions.