In Western societies, the guinea pig has enjoyed widespread popularity as a household pet since the introduction by European traders in the 16th century. If handled correctly early in life, guinea pigs become amenable to being picked up and carried, and seldom bite or scratch. Guinea pig’s who become familiar with their owner will whistle on the owner’s approach; they will also learn to whistle in response to the rustling of plastic bags or the refrigerator door being opened where their food is stored.
The guinea pig (also commonly called the Cavy after its scientific name, Cavia porcellus) is a species of rodent belonging to the family Caviidae and the genus Cavia. Despite their common name, these animals are not pigs, nor do they come from Guinea. They originated in the Andes, and studies based on biochemistry and hybridization suggest they are domesticated descendants and therefore do not exist naturally in the wild. These rodent-type pets akin to a mouse, beaver, or hamster were traded worldwide and are not a pig at all but named for their pig-like squeal. Their docile nature, their responsiveness to handling and feeding, and the relatively easy of caring for them, make guinea pigs a popular pet. Guinea pigs make good very beginner pets.
The common guinea pig was first domesticated as early as 5000 BC for food by tribes in the Andean region of South America (present-day Ecuador, Peru, and Bolivia).
Guinea pigs are large for rodents, weighing between 700 and 1200g (1.5-2.5 pounds), and measuring 20-25 cm (8–10 inches) in length. They typically live an average of four to five years, but may live as long as eight years. According to the 2006 Guinness Book of Records the longest living guinea pig survived 14 years, 10.5 months.
Domesticated guinea pigs thrive in groups of two or more; groups of sows, or groups of one or more sows and a neutered boar are common combinations. Guinea pigs learn to recognize and bond with other individual guinea pigs, and testing of boars shows that their neuroendocrine stress response is significantly lowered in the presence of a bonded female when compared to the presence of unfamiliar females. Groups of boars may also get along, provided that their cage has enough space, they are introduced at an early age, and no females are present. Domestic guinea pigs have developed a different biological rhythm from their wild counterparts, and have longer periods of activity followed by short periods of sleep in between. Activity is scattered randomly over the 24 hours of the day; aside from avoidance of intense light, no regular circadian patterns are apparent.
Domestic guinea pigs generally live in cages, although some owners of large numbers of guinea pigs will dedicate entire rooms to their pets. Cages with solid or wire mesh floors are used, although wire mesh floors can cause injury and may be associated with an infection commonly known as bumblefoot (ulcerative pododermatitis). "Cubes and Coroplast" (or C&C) style cages are now a common choice. Cages are often lined with wood shavings or a similar material. Bedding made from Red Cedar and pine, both softwoods, was commonly used in past decades, but these materials are now believed to contain harmful phenols (aromatic hydrocarbons) and oils. Safer beddings include those made from hardwoods (such as aspen), paper products, and corncob materials are other alternatives. Guinea pigs tend to be messy within their cages; they often jump into their food bowls or kick bedding and feces into them, and their urine crystallizes on cage surfaces and can be difficult to remove. After its cage has been cleaned, a guinea pig will typically urinate and drag the lower body across the floor of the cage to mark its territory. Male guinea pigs may also mark their territory in this way when they are taken out of their cages.
Guinea pigs do not generally thrive when housed with other species. Co-housing of guinea pigs with other rodents such as gerbils and hamsters may increase instances of respiratory and other infections, and such rodents may act aggressively toward the guinea pig.
Guinea pigs can learn complex paths to food, and can accurately remember a learned path for months. Their strongest problem solving strategy is motion. While guinea pigs can jump small obstacles, they cannot climb, and are not particularly agile. They startle extremely easily, and will either freeze in place for long periods or run for cover with rapid, darting motions when they sense danger. Larger groups of startled guinea pigs will "stampede", running in haphazard directions as a means of confusing predators. When excited, guinea pigs may repeatedly perform little hops in the air (known as "popcorning"), a movement analogous to the ferret's war dance. They are also exceedingly good swimmers. Like many rodents, guinea pigs sometimes participate in social grooming, and they regularly self-groom. Guinea pigs have poor sight, but well-developed senses of hearing, smell, and touch. Vocalization is the primary means of communication between members of the species
Grass is the guinea pig's natural diet. Their molars are particularly suited for grinding plant matter, and grow continuously throughout the animal's life. Most grass-eating mammals are quite large and have a long digestive tract; while guinea pigs have much longer colons than most rodents, they must also supplement their diet by coprophagy, the eating of their own feces. Guinea pigs benefit from feeding on fresh grass hay, such as timothy hay, in addition to food pellets, which are often based from timothy. Alfalfa is also a popular food choice; most guinea pigs will eat large amounts of alfalfa when offered it, though there exists some controversy over the feeding of alfalfa to adult guinea pigs. Some pet owners and veterinary organizations have advised that, as a legume rather than a grass hay, alfalfa consumed in large amounts may lead to obesity, as well as bladder stones due to excess calcium, in any but pregnant and very young guinea pigs. However, published scientific sources mention alfalfa as a source for replenishment of protein, amino acids, and fiber.
Like humans, but unlike most other mammals, guinea pigs cannot synthesize their own vitamin C and must obtain this vital nutrient from food. If guinea pigs do not ingest enough vitamin C, they can suffer from potentially fatal scurvy. Guinea pigs require about 10 mg (0.15 gr) of vitamin C daily (20 mg (0.31 gr) if pregnant), which can be obtained through fresh, raw fruits and vegetables (such as broccoli, apple, cabbage, carrot, celery, and spinach) or through dietary supplements. Healthy diets for guinea pigs require a complex balance of calcium, magnesium, phosphorus, potassium, and hydrogen ions; adequate amounts of vitamins E, A, and D are also necessary. Imbalanced diets have been associated with muscular dystrophy, metastatic calcification, difficulties with pregnancy, vitamin deficiencies, and teeth problems. Guinea pigs tend to be fickle eaters when it comes to fresh fruits and vegetables, having learned early in life what is and is not appropriate to consume, and their habits are difficult to change after maturity. They do not respond well to sudden changes in diet; they may stop eating and starve rather than accepting new food types.
A number of plants are poisonous to guinea pigs, including bracken, bryony, buttercup, charlock, deadly nightshade, foxglove, hellebore, hemlock, Lily of the Valley, mayweed, monkshood, privet, ragwort, rhubarb, speedwell, toadflax, and wild celery. Additionally, any plant that grows from a bulb (e.g., tulip and onion) is normally considered poisonous.
Common ailments in domestic guinea pigs include respiratory tract infections, diarrhea, scurvy (vitamin C deficiency, typically characterized by sluggishness), abscesses due to infection (often in the neck, due to hay embedded in the throat, or from external scratches), and infections by lice, mites, or fungus.