Guinea pigs are highly social herd animals that suffer when kept alone. Understanding their social and environmental needs transforms welfare outcomes for these popular small pets.
Guinea pig welfare is frequently compromised through solitary housing and inadequate space, both of which cause measurable stress. Animals kept alone show increased cortisol, reduced exploration, and depression-like behavioral states. The Swiss law requiring social housing reflects the strength of this evidence. Housing standards need updating: most commercial cages sold for guinea pigs are too small for adequate exercise. Vitamin C deficiency from inadequate fresh vegetables or poor pellet quality causes joint pain and dental problems. Guinea pigs are stoic animals that hide illness until severe — regular health checks are essential. Education at the point of sale is critically needed.