Guinea Pig

Guinea pigs (also commonly called cavies after their scientific name) are rodents belonging to the family Caviidae and the genus Cavia. Despite their common name, the animals are not pigs, nor do they come from Guinea. They are originally native to the Andes, and while they are no longer extant in the wild, they are closely related to several species which are commonly found in the grassy plains and plateaus of the region. The guinea pig plays an important role in the folk culture of indigenous South Americans, especially as a food source, but also in folk medicine and in community religious ceremonies. Since the 1960s, efforts have been made to increase consumption of the animal outside South America.

In Western societies, the guinea pig has enjoyed widespread popularity as a household pet since its introduction by European traders in the sixteenth century. Because of its docile nature, the relative ease of caretaking, and its responsiveness to handling and feeding, the guinea pig remains a popular pet choice. Organizations devoted to competitive breeding of guinea pigs have been formed worldwide, and a large number of specialized breeds of guinea pig, with varying coat colors and compositions, are cultivated by breeders.

"Guinea pig" is also used as a by-word in English for a subject of experimentation; this usage became common in the first half of the twentieth century. Biological experimentation on guinea pigs has been carried out since the seventeenth century; the animals were frequently used in scientific contexts in the nineteenth and twentieth centuries, but have since been largely replaced by other rodents, such as mice and rats. They are still used in research primarily as models for human medical conditions such as juvenile diabetes, tuberculosis, scurvy, and pregnancy complications.

The common guinea pig was first domesticated as early as 5000 BC for food by mountain tribes in the Andean region of South America (present-day Ecuador, Peru and Bolivia).[3] Statues dating from ca. 500 BC to 500 AD which depict guinea pigs have been unearthed in archaeological digs in Peru and Ecuador.[4] From ca. 1200 AD to the Spanish conquest in 1532, selective breeding resulted in many varieties of domestic guinea pigs, which form the basis for some of the modern domestic breeds.[5] They continue to be a food source in the region; most households in the Andean highlands raise the animal, which subsists off the family's vegetable scraps in kitchens. Folklore traditions involving guinea pigs are numerous; they are exchanged as gifts, used in customary social and religious ceremonies, and are frequently referenced in spoken metaphors. They also play a role in traditional healing rituals by folk doctors, or curanderos, who use the animals to diagnose diseases such as jaundice, rheumatism, arthritis, and typhus.[8] They are rubbed against the bodies of the sick, and are seen as a supernatural medium.[9] The animal may also be cut open and its entrails examined to determine whether or not the cure was effective.[10] These methods are widely accepted in many parts of the Andes, where Western medicine is either unavailable or distrusted.

Spanish, Dutch and English traders brought guinea pigs to Europe, where they quickly became popular as exotic pets among the upper classes and royalty, including Queen Elizabeth I.[12] The earliest known written account of the guinea pig dates from 1547, in a description of the animal from Santo Domingo; because cavies are not native to Hispaniola, the animal must have been introduced there by Spanish travelers The guinea pig was first described in the West in 1554 by the Swiss naturalist Konrad Gesner. Its binomial scientific name was first used by Erxleben in 1777; it is an amalgam of Pallas's generic designation (1766) and Linnaeus's specific conferral (1758).

Guinea pigs are large for rodents, weighing between 1 and 2.5 pounds (700–1200 g), and measuring 8–10 inches (20–25 cm) long.[24] They typically live an average of four to five years, and occasionally as long as eight years.[25] According to the 2006 Guinness Book of Records the longest living guinea pig survived 14 years, 10.5 months.

In the 1990s, a minority scientific opinion emerged proposing that caviomorphs, such as guinea pigs, chinchillas and degus, are not actually rodents and should be reclassified as a separate order of mammals (similar to lagomorphs).[27][28] Subsequent research using wider sampling has restored consensus among mammalian biologists that the current classification of rodents as monophyletic is justified.

Cavia porcellus is not found naturally in the wild; it is likely descendant from some closely related species of cavies, such as Cavia aperea, Cavia fulgida, and Cavia tschudii, which are still commonly found in various regions of South America. Some species of cavy identified in the twentieth century, such as Cavia anolaimae and Cavia guianae, may in fact be domestic guinea pigs that have become feral by reintroduction into the wild. Wild cavies are found on grassy plains and occupy an ecological niche similar to that of the cow. They are social, living in the wild in small groups which consist of several females (sows), a male (boar), and the young (which in a break with the preceding porcine nomenclature are called pups). They move together in groups (herds) eating grass or other vegetation, and do not store food. While they do not burrow or build nests, they frequently seek shelter in the burrows of other animals, as well as in crevices and tunnels formed by vegetation.[31] They are crepuscular, tending to be most active during dawn and dusk, when it is harder for predators to spot them.

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 also 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, though 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, were commonly used in past decades but are now believed to contain harmful phenols (aromatic hydrocarbons) and oils. Safer beddings include those made from hardwoods (such as aspen or hemp); paper products and corn cob 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. Cohousing 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 towards the guinea pig. Larger animals may regard guinea pigs as prey, though some (such as dogs) can be trained to accept them. Opinion is divided over the cohousing of guinea pigs and domestic rabbits. Some published sources say that guinea pigs and rabbits complement each other well when sharing a cage. However, as lagomorphs, rabbits have different nutritional requirements, and so the two species cannot be fed the same food. Rabbits may also harbor diseases (such as the respiratory infections Bordetella and Pasteurella), which guinea pigs are susceptible to. Even the dwarf rabbit is much stronger than the guinea pig and may cause intentional or inadvertent injury.

Guinea pigs can learn complex paths to food; they can accurately remember the learned path for months. While guinea pigs can jump small obstacles, they cannot climb, and are not particularly agile. However, 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 confusion. 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.