What is a guinea pig?

Guinea Pig,

The Guinea pig (also commonly called the cavy after its scientific name) 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 are native to the Andes, and while no longer extant in the wild, they are closely related to several species that are commonly found in the grassy plains and plateaus of the region. The guinea pig plays an important role in the folk culture of many indigenous South American groups, especially as a food source, but also in folk medicine and in community religious ceremonies.[1] Since the 1960s, efforts have been made to increase consumption of the animal outside South America.[2]

In Western societies, the guinea pig has enjoyed widespread popularity as a household pet since its introduction by European traders in the 16th century. Their docile nature, their responsiveness to handling and feeding, and the relative ease of caring for them, continue to make the guinea pig a popular pet. Organizations devoted to competitive breeding of guinea pigs have been formed worldwide, and many specialized breeds of guinea pig, with varying coat colors and compositions, are cultivated by breeders.

Guinea pig is also used as a metaphor in English for a subject of experimentation; this usage became common in the first half of the 20th century. Biological experimentation on guinea pigs has been carried out since the 17th century; the animals were frequently used as a model organism in the 19th and 20th 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.

History

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). Statues dating from ca. 500 BC to 500 AD that depict guinea pigs have been unearthed in archaeological digs in Peru and Ecuador. The Moche people of ancient Peru worshipped animals and often depicted the guinea pig in their art. 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. 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. Folklore traditions involving guinea pigs are numerous; they are exchanged as gifts, used in customary social and religious ceremonies, and 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. They are rubbed against the bodies of the sick, and are seen as a supernatural medium. Black guinea pigs are considered especially useful for diagnoses. The animal also may be cut open and its entrails examined to determine whether the cure was effective. 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. 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).

Name

The scientific name of the common species is Cavia porcellus, with porcellus being Latin for "little pig". Cavia is New Latin; it is derived from cabiai, the animal's name in the language of the Galibi tribes once native to French Guiana. Cabiai may be an adaptation of the Portuguese çavia (now savia), which is itself derived from the Tupi word saujá, meaning rat. Guinea pigs are called quwi or jaca in Quechua and cuy or cuyo (pl. cuyes, cuyos) in the Spanish of Ecuador, Peru and Bolivia. Paradoxically, breeders tend to use the more formal "cavy" to describe the animal, while in scientific and laboratory contexts it is far more commonly referred to by the more colloquial "guinea pig".

How the animals came to be thought of as "pigs" is not clear. They are built somewhat like pigs, with large heads relative to their bodies, stout necks, and rounded rumps with no tail of any consequence; some of the sounds they emit are very similar to those made by pigs, and they also spend a large amount of time eating. They can survive for long periods in small quarters, like a 'pig pen', and were thus easily transported on ships to Europe.

The animal's name carries porcine connotations in many European languages. The German word for them is Meerschweinchen, literally "little sea pigs". (The Polish świnka morska and Russian морская свинка mean exactly the same.) This derives from nautical history: sailing ships stopping to reprovision in the New World would pick up stores of guinea pigs, which provided an easily transportable source of fresh meat; Meerschwein is German for porpoise, which was another food source for sailors. The French term is Cochon d'Inde (Indian pig); the Dutch used to call it guinees biggetje (Guinean piglet) or Spaanse rat (Spanish rat) in some dialects, and in Portuguese the guinea pig is sometimes referred to as porquinho da Índia (little Indian pig). This is not universal; for example, the common word in Spanish is conejillo de Indias (little rabbit of India / the Indies).

The origin of "guinea" in "guinea pig" is harder to explain. One theory is that the animals were brought to Europe by way of Guinea, leading people to think they had originated there. "Guinea" was also frequently used in English to refer generally to any far-off, unknown country, and so the name may simply be a colorful reference to the animal's foreignness. Another theory suggests the "guinea" in the name is a corruption of "Guiana", an area in South America, though the animals are not native to that region. A common misconception is that they were so named because they were sold for the price of a guinea coin; this theory is untenable, because the guinea was first struck in England in 1663, and William Harvey used the term "Ginny-pig" as early as 1653. Others believe "guinea" may be an alteration of the word coney (rabbit); guinea pigs were referred to as "pig coneys" in Edward Topsell's 1607 treatise on quadrupeds.

Traits and environment

Guinea pigs are large for rodents, weighing between 700 and 1200g (1.5-2.5 pounds), and measuring between 20 and 25cm (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.

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

Natural habitat

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 20th century, such as Cavia anolaimae and Cavia guianae, may 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. They are crepuscular, tending to be most active during dawn and dusk, when it is harder for predators to spot them.

Domestic habitat

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 corn cob 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. 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 toward 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), to which guinea pigs are susceptible. Even the dwarf rabbit is much stronger than the guinea pig and may cause intentional or inadvertent injury.

Breeding

The guinea pig is able to breed year-round, with birth peaks usually coming in the spring; as many as five litters can be produced per year. The gestation period lasts from 59–72 days, with an average of 63–68 days. Because of the long gestation period and the large size of the pups, pregnant females may become large and eggplant-shaped, although the change in size and shape varies. Newborn pups are well-developed with hair, teeth, claws and partial eyesight; they are immediately mobile, and begin eating solid food immediately, though they continue to suckle. Litters yield 1–6 pups, with an average of three;the largest recorded litter size is 17. In smaller litters, difficulties may occur during labour due to over-sized pups. Large litters result in higher incidences of stillbirth, but because the pups are delivered at an advanced stage of development, lack of access to the mother's milk has little effect on the mortality rate of newborns. Cohabitating females assist in mothering duties if lactating.

Male and female guinea pigs do not differ in external appearance apart from general size. The position of the anus is very close to the genitals in both sexes. Female genitals are distinguished by a Y-shaped configuration formed from a vulvar flap; while the male genitals may look similar with the penis and anus forming a like shape, the penis will protrude if pressure is applied to the surrounding hair. The male's testes may also be visible externally from scrotal swelling.

Males reach sexual maturity at 3–5 weeks; females can be fertile as early as four weeks and can carry litters before they are adults. Females that have never given birth commonly develop irreversible fusing of the pubic symphysis, a joint in the pelvis, after six months of age. If they become pregnant after this has happened, the birth canal will not widen sufficiently; this may lead to dystocia and death as they attempt to give birth. Females can become pregnant 6–48 hours after giving birth, but it is not healthy for a female to be thus constantly pregnant.

Toxemia of pregnancy is common and kills many pregnant females. Signs of toxemia include anorexia, lack of energy, excessive salivation, a sweet or fruity breath odor due to ketones, and seizures in advanced cases. Pregnancy toxemia appears to be most common in hot climates. Other serious complications of pregnancy can include a prolapsed uterus, hypocalcemia, and mastitis.




This information was retrieved from Wikipedia.com