Guinea Pig Care: What Every Owner Should Know
Guinea pigs — cavies (Cavia porcellus) — no longer exist in the wild; they descend from an extinct South American species and have been shaped by selective breeding into some twenty phenotypes. They are tailless rodents weighing 700–1100 g and measuring 20–25 cm, with a captive lifespan that can reach fourteen years. They are gregarious, crepuscular animals that form social hierarchies around a dominant alpha male, and they are strict herbivores that depend on their owners for food.
The Vitamin C Rule
The single fact every guinea pig owner must internalize is that guinea pigs cannot make their own vitamin C. They lack the enzyme L-gulonolactone oxidase needed to synthesize ascorbic acid from glucose, so they require a regular dietary source — roughly 10–25 mg/kg of body weight daily for adults, and 30 mg/kg or more for growing, pregnant, lactating, or ill individuals. Many commercial guinea pig pellets contain a stabilized, heat- and light-resistant form of vitamin C precisely for this reason. One practical caution: supplementing vitamin C through the drinking water is discouraged, because the vitamin breaks down and the changed taste can reduce water intake.
Other Health Concerns
Urolithiasis (stones) is common and is usually made of calcium carbonate precipitating out of normal urine; females are more often diagnosed with ureter and bladder stones.
Cystic ovarian disease is the most common reproductive-tract disorder in female guinea pigs ("sows").
Pododermatitis is likewise common and can affect all four feet; inappropriate flooring and obesity are the main predisposing factors, so soft, clean substrate and weight control matter.
Diet in Practice
Because the animals are strict herbivores with a hard requirement for vitamin C, the diet should center on guinea-pig-specific pellets plus generous grass hay and vitamin-C-rich vegetables, rather than generic rodent mix or table scraps. Getting the vitamin C baseline right prevents the large majority of the metabolic problems seen in this species.