The guinea pig (or cavy) is a small rodent native to the Andes Mountains of South America. They are popular as pets because of their docile temperament (they rarely bite) and relatively clean habits. Guinea pigs live an average of 5 to 6 years and range in weight from 700 to 1100 grams (1 1/2 to 2 1/2 lbs.). There are three basic varieties: the common shorthair, the Abyssinian, which has whorls in its haircoat, and the longhair Peruvian. All types make great pets for both children and adults.

Housing

Guinea pigs should be kept in cages when they are alone. The enclosure must be roomy enough to allow normal activity and at least 10 inches high. The top can be open. The flooring should be solid since wire mesh can cause foot and leg injuries. Bedding must be clean, absorbent, and dust-free. Shredded paper, recycled newspaper products (Carefresh®), and aspen wood shavings are suitable. Pine or cedar shavings contain aromatic oils and are not recommended. Cages should have adequate ventilation and be cleaned frequently. Guinea pigs are startled by loud noises or sudden movements and may start to run or vocalize. It is best if the cage is kept in a relatively quiet area. A sleep-box can be made out of cardboard or wood.

Dietary Recommendations

The dietary needs of pet guinea pigs have not been studied as extensively as rabbits. Wild guinea pigs consume a variety of vegetation. Domestically bred guinea pigs are also herbivores and can be fed fresh vegetables once they are gradually added to the diet. A diet high in fiber is recommended: guinea pig pellets, and ad lib alfalfa or grass hay like timothy or orchard grass (Oxbow Pet Products). This can be supplemented with greens high in fiber and vitamin C.

Guinea pigs have a dietary requirement for Vitamin C (ascorbic acid) and need approximately 25 mg/day and more during stress, illness and pregnancy (50-100 mg). Although the pellets generally contain ascorbic acid when milled, the 90-day shelf life of this vitamin makes the content of some pellets negligable. A diet supplemented with greens high in ascorbic acid is recommended: spinach, kale, parsley, cabbage, chickory, and bell peppers. Vitamin C supplementation may be necessary in those pets that do not obtain enough ascorbic acid from the diet. Pediatric liquid vitamin C supplements are available in pharmacies and can be added to the food daily. Water supplementation is not as effective because vitamin C breaks down quickly once exposed to light. Water bottles with sipper tubes are useful, but the water should be changed daily, and the sipper tips need to be checked regularly for clogging. Sudden changes in diet may cause anorexia or diarrhea and should be avoided

Guinea pigs reach sexual maturity as young as 6 to 10 weeks of age. If breeding, females should be mated by 7 months of age. If the first breeding occurs at an older age, serious complications with delivery can occur, and cesarean section is sometimes required to save the mother and her babies. This is because the pubic symphysis (part of the pelvis) fuses as a guinea pig approaches 1 year of age and this narrows the birth canal. An uncomplicated delivery usually requires less than 1 hour. Gestation period averages 63 days. Litter sizes can range from one to six, but three to four babies are most common. Babies are born relatively mature; they are fully haired, they have teeth, their eyes are open, and they start eating solid food within a few days. Young guinea pigs are usually weaned at 2 to 4 weeks of age.

Common Medical Problems

Guinea pigs are susceptible to a wide variety of ailments. Respiratory infections, dental disease (see website article on rodent dentistry), skin conditions, and digestive disturbances can be significant problems. Clinical signs of disease such as diarrhea, anorexia, weight loss, and difficulty breathing can be serious. If your guinea pig becomes lethargic or has any of these signs, a veterinarian should be consulted as soon as possible.