Guinea pigs (Cavia porcellus) are highly social, vocal, and cognitively engaged small mammals that deserve far more thoughtful care than they typically receive. Often considered "easy starter pets," they are in fact complex animals with specific welfare needs that are frequently unmet in traditional hutch-based husbandry.
Guinea pigs are highly social and must live with at least one compatible companion. Solitary guinea pigs suffer significantly: they show distress vocalisation, reduced activity, and stress-related health problems. In Switzerland, it is illegal to keep guinea pigs alone. Compatible groupings: same-sex pairs or groups, or neutered male with females. Introduction requires a careful process to avoid fighting.
Traditional small hutches are wholly inadequate. Minimum RSPCA guidance: a hutch of 120cm x 60cm plus a run of 150cm x 60cm for two guinea pigs — and this is a minimum. Guinea pigs are crepuscular, most active at dawn and dusk, and benefit from large indoor or outdoor enclosures that allow running, exploring, and natural behaviour. Indoor housing is often preferable in the UK climate, especially for shorter-haired breeds.
Guinea pigs have a critical nutritional requirement that distinguishes them from many other small mammals: they cannot synthesise vitamin C and must receive dietary sources daily. Deficiency causes scurvy — painful joint swelling, reluctance to move, and weight loss. Sources: fresh leafy greens (kale, broccoli, leafy herbs), bell peppers, and fresh grass. Pellets should be guinea pig-specific (vitamin C-enriched); rabbit pellets are inappropriate. Hay should constitute 80% of the diet for dental health and gut motility.