Guinea pig

Theguinea pigordomestic guinea pig(Cavia porcellus), also known as thecavyordomestic cavy(/ˈkeɪvi/KAY-vee), is a species ofrodentbelonging to the genusCavia, familyCaviidae.Breederstend to use the name "cavy" for the animal, but "guinea pig" is more commonly used in scientific and laboratory contexts.Despite their name, guinea pigs are not native toGuinea, nor are they closely related topigs. Instead, they originated in theAndesregion ofSouth America, where wild guinea pigs can still be found today.Studies based onbiochemistryand DNAhybridizationsuggest they aredomesticatedanimals that do not exist naturally in the wild, but are descendants of a closely related cavy species such asC. tschudii.Originally, they were domesticated aslivestock(source of meat) in the Andean region and are still consumed in some parts of the world.
InWestern society, the guinea pig has enjoyed widespread popularity as apetsince its introduction to Europe and North America by European traders in the 16th century. Their docile nature, friendly responsiveness to handling and feeding, and the relative ease of caring for them have continued to make guinea pigs a popular choice of household pets. Consequently, organizations devoted to thecompetitive breedingof guinea pigs have been formed worldwide. Throughartificial selection, manyspecialized breedswith varyingcoatcolors and textures have been selected bybreeders.
Livestock breeds of guinea pig play an important role infolk culturefor manyindigenous Andean peoples, especially as a food source.They are not only used infolk medicineand in community religious ceremoniesbut also raised for their meat. Guinea pigs are an important culinary staple in theAndes Mountains, where it is known ascuy. Lately, marketers tried to increase their consumption outside South America.
Biological experimentationon domestic guinea pigs has been carried out since the 17th century. The animals were used so frequently asmodel organismsin the 19th and 20th centuries that theepithetguinea pigcame into use to describe ahuman test subject. Since that time, they have mainly been replaced by other rodents, such asmiceandrats. However, they are still used in research, primarily as models to study such human medical conditions asjuvenile diabetes,tuberculosis,scurvy(like humans, they require dietary intake ofvitamin C), andpregnancy complications.
Cavia porcellusis not found naturally in the wild; it is likely descended from closely related species ofcavies, such asC. aperea,C. fulgida, andC. tschudii. These closely related species are still commonly found in various regions of South America.Studies from 2007 to 2010 applyingmolecular markers,and morphometric studies on the skull and skeletalmorphologyof current and mummified animalsrevealed the ancestor to be most likelyC. tschudii. Some species of cavy, identified in the 20th century asC. anolaimaeandC. guianae, may be domestic guinea pigs that have becomeferalby reintroduction into the wild.
Regionally known ascuy(Spanish word derived fromquechuaquwi), the guinea pig was firstdomesticatedas early as 5000 BC for food by tribes in theAndeanregion ofSouth America(the present-day southern part of Colombia, Ecuador, Peru, and Bolivia),some thousands years after the domestication of the South Americancamelids.TheMochepeople of ancient Peru worshipped animals and often depicted the guinea pig in their art.
Early accounts from Spanish settlers state that guinea pigs were the preferred sacrificial animal of the Inca people native to Peru.These claims are supported by archaeological digs and transcribed Quechua mythology,providing evidence that sacrificial rituals involving guinea pigs served many purposes in society such as appeasing the gods, accompanying the dead, or reading the future.
From about 1200 to theSpanish conquestin 1532, the indigenous people used selective breeding to develop many varieties of domestic guinea pigs, forming the basis for some modern domestic breeds.They continue to be a food source in the region; many households in the Andean highlands raise the animal.
In the early 1500s,Spanish,Dutch, andEnglishtraders took guinea pigs to Europe, where they quickly became popular asexotic petsamong the upper classes and royalty, includingQueen Elizabeth I.The earliest known written account of the guinea pig dates from 1547, in a description of the animal fromSanto Domingo. Because cavies are not native toHispaniola, the animal was believed to have been earlier introduced there by Spanish travelers.However, based on more recent excavations on West Indian islands, the animal may have been introduced to the Caribbean around 500 BC by ceramic-making horticulturalists from South America.It was present in theOstionoidperiod onPuerto Rico, for example, long before the advent of the Spaniards.
The guinea pig was first described in the West in 1554 by theSwissnaturalistConrad Gessner.Itsbinomial scientific namewas first used byErxlebenin 1777; it is an amalgam ofPallas'genericdesignation (1766) andLinnaeus'specificconferral (1758).
The earliest-known European illustration of a domestic guinea pig is a painting (artist unknown) in the collection of theNational Portrait Galleryin London, dated to 1580, which shows a girl in a typical Elizabethan dress holding a tortoise-shell guinea pig in her hands. She is flanked by her two brothers, one of whom holds a pet bird.The picture dates from the same period as the oldest recorded guinea pig remains in England, which are a partial cavy skeleton found atHill Hall, an Elizabethan manor house inEssex, and dated to around 1575.
The scientific name of the common species isCavia porcellus, withporcellusbeingLatinfor "littlepig".CaviaisNeo-Latin; it is derived fromcabiai, the animal's name in the language of theGalibitribes once native toFrench Guiana.Cabiaimay be an adaptation of thePortugueseçavia(nowsavia), which is itself derived from theTupiwordsaujá, meaning rat.
The origin of "guinea" in "guinea pig" is hard to explain. One proposed explanation is that the animals were brought to Europe by way ofGuinea, leading people to think they had originated there."Guinea" was also frequently used in English to refer generally to any far-off, unknown country, so the name may be a colorful reference to theanimal's exotic origins.
Another hypothesis suggests the "guinea" in the name is a corruption of "Guiana", an area in South America.A common misconception is that they were so named because they were sold for the price of aguinea coin. This hypothesis is untenable because the guinea was first struck in England in 1663, andWilliam Harveyused the term "Ginny-pig" as early as 1653.Others believe "guinea" may be an alteration of the wordconey(rabbit); guinea pigs were referred to as "pig coneys" inEdward Topsell's 1607 treatise onquadrupeds.
How the animals came to be called "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 spend a large amount of time eating.They can survive for long periods in small quarters, like a "pig pen", and were easily transported by ship to Europe.
Guinea pigs are calledquwiorjacainQuechuaandcuyorcuyo(pluralcuyes, cuyos) in theSpanishof Ecuador, Peru, and Bolivia.
The animal's name alludes to pigs in many European languages. TheGermanword for them isMeerschweinchen, literally "little sea pig", inPolishthey are calledświnka morska, inHungarianastengerimalac, and inRussian:морская свинка,romanized:morskaya svinka. The German word derives from theMiddle High GermannameMerswin. This word originally meant "dolphin" and was used because of the animals' grunting sounds (which were thought to be similar).
Many other, possibly less scientifically based, explanations of the German name exist. For example, sailing ships stopping to reprovision in theNew Worldwould pick up guinea pig stores, providing an easily transportable source of fresh meat. TheFrenchterm iscochon d'Inde(Indian pig), orcobaye; theDutchcalled itGuinees biggetje(Guinean piglet), or cavia (in some Dutch dialects it is calledSpaanse rat); and in Portuguese, the guinea pig is variously referred to ascobaia, from theTupiword via its Latinization, or asporquinho da Índia(little Indian pig). This association with pigs is not universal among European terms; for example, the common word in Spanish isconejillo de Indias(little rabbit of the Indies).
The Chinese refer to the animal as豚鼠(túnshǔ, "pig mouse"), and sometimes as荷蘭豬(hélánzhū, 'Netherlands pig') or天竺鼠(tiānzhúshǔ, "Indian mouse"). The Japanese word for guinea pig isモルモット(morumotto), which derives from the name of another mountain-dwelling rodent, themarmot. This word is how the guinea pigs were called by Dutch traders, who first brought them toNagasakiin 1843. The other, and less common, Japanese word for guinea pig, using kanji, is 天竺鼠 (てんじくねずみ ortenjiku-nezumi), which translates as "India rat".
Guinea pigs are relatively large for rodents. In pet breeds, adults typically weigh between 700 and 1,200 g (1.5 and 2.6 lb) and measure between 20 and 25 cm (8 and 10 in) in length.Some livestock breeds weigh 3 kg (6.6 lb) when full grown.Pet breeds live an average of four to five years but may live as long as eight years.According toGuinness World Records, as of 2006, the longest-lived guinea pig was 14 years, 10 months, and 2 weeks old.Most guinea pigs have fur, but one laboratory breed adopted by some pet owners, theskinny pig, is mostly furless. In contrast, several breeds have long fur, such as thePeruvian, theSilkie, and theTexel. They have four front teeth and small back teeth. Their front teeth grow continuously, so guinea pigs chew on materials such as wood to wear them down to prevent them from becoming too long.In the 1990s, a minority scientific opinion emerged proposing thatcaviomorphssuch as guinea pigs,chinchillas, anddegusare not actually rodents, and should bereclassifiedas a separateorderof mammals (similar to the rodent-likelagomorphswhich includes rabbits and hares).Subsequent research usingwider samplingrestored the consensus among mammalian biologists regarding the current classification of rodents, including guinea pigs, asmonophyletic.
Wild cavies are found on grassy plains and occupy anecological nichesimilar to that ofcattle. They are social animals, living in the wild in small groups ("herds") that consist of several females ("sows"), a male ("boar"), and their young ("pups" not "piglets", a break with the precedingporcinenomenclature). Herds of animals move together, eating grass or other vegetation, yet do not store food.While they do notburrowthemselves or build nests, they frequently seek shelter in the burrows of other animals, as well as in crevices and tunnels formed by vegetation.They arecrepuscularand tend to be most active during dawn and dusk when it is harder for predators to spot them.
Male and female guinea pigs do not significantlydiffer in appearanceapart from general size. The position of theanusis very close to thegenitalsin both sexes.Sexing animalsat a young age must be done by someone trained in the differences. Female genitals are distinguished by a Y-shaped configuration formed from avulvar flap. While male genitals may look similar, with thepenisand anus forming a similar shape, the penis will protrude if pressure is applied to the surrounding hair anterior to the genital region.The male'stestesmay also be visible externally fromscrotalswelling.
Guinea pigs can learn complex paths to food and can accurately remember a learned path for months. Their most robustproblem-solvingstrategy is motion.While guinea pigs can jump small obstacles, they cannot jump very high. Most of them are poor climbers and are not particularly agile. They startle easily, and when they sense danger, they either freeze in place for long periods or run for cover with rapid, darting motions.Larger groups of startled guinea pigs "stampede", running in haphazard directions as a means of confusing predators.When happily excited, guinea pigs may (often repeatedly) perform little hops in the air (a movement known as "popcorning"), analogous to theferret'swar danceor rabbit happy hops (binkies). Guinea pigs are also good swimmers,although they do not like being wet and infrequently need bathing.
Like many rodents, guinea pigs sometimes participate insocial groomingand regularly self-groom.A milky-white substance is secreted from their eyes and rubbed into the hair during the grooming process.Groups of boars often chew each other's hair, but this is a method of establishing hierarchy within a group, rather than a social gesture.Dominance is also established through biting (especially of the ears),piloerection, aggressive noises, head thrusts, and leaping attacks.Non-sexual simulatedmountingfor dominance is also common among same-sex groups.
Guinea pig eyesight is not as good as that of a human in terms of distance and color, but they have a wider angle of vision (about 340°) and see in partial color (dichromacy). They have well-developed senses of hearing,smell, and touch.
Guinea pigs have developed a differentbiological rhythmfrom their wild counterparts and have longer periods of activity followed by short sleep in between.Activity is scattered randomly throughout the day; aside from an avoidance of intense light, no regularcircadian patternsare apparent.
Guinea pigs do not generally thrive when housed with other species. Larger animals may regard guinea pigs asprey, though somedogsandcatscan be trained to accept them.Opinion is divided over the cohousing of guinea pigs andrabbits. Some published sources say that guinea pigs and rabbits complement each other well when sharing a cage.However, rabbits have different nutritional requirements; aslagomorphs, they synthesize their ownvitamin C, so the two species will not thrive if fed the same food when housed together.Rabbits may also harbor diseases (such as respiratory infections fromBordetellaandPasteurella), to which guinea pigs are susceptible.Housing guinea pigs with other rodents such asgerbilsandhamstersmay increase instances of respiratory and other infections,and such rodents may act aggressively toward guinea pigs.
Vocalization is the primary means of communication between members of the species.These are the most common sounds made by the guinea pig:
Males (boars) reachsexual maturityin 3–5 weeks. Similarly, females (sows) can be fertile as early as four weeks old and carry litters before becoming fully grown adults.A sow can breed year-round (with spring being the peak). A sow can have as many as five litters in a year, but six is theoretically possible.Unlike the offspring of mostrodents, which arealtricialat birth, newborn cavy pups areprecocial, and are well-developed with hair, teeth, claws, and partial eyesight.The pups are immediately mobile and begin eating solid food immediately, though they continue tosuckle.  Sows can once again become pregnant 6–48 hours after giving birth, but it is not healthy for a female to be constantly pregnant.
Thegestationperiod lasts from 59–72 days (1.9–2.4 months), with an average of 63–68 days (2.1–2.2 months).Because of the long gestation period and the large size of the pups, pregnant sows may become large andeggplant-shaped, although the change in size and shape varies depending upon the size of the litter.Littersize ranges from one to six, with three being the average;the largest recorded litter size is 9.The guinea pig mother only has two nipples, but she can readily raise the more average-sized litters of 2 to 4 pups.In smaller litters, difficulties may occur duringlabourdue to oversized pups. Large litters result in higher incidences ofstillbirth, 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 iflactating;guinea pigs practicealloparental care, in which a sow may adopt the pups of another. This might take place if the original parents die or are, for some reason, separated from them. This behavior is common and is seen in many other animal species, such as the elephant.
Toxemia of pregnancy(hypertension) is a common problem and kills many pregnant females. Signs of toxemia include anorexia (loss of appetite),lack of energy,excessive salivation, asweet or fruity breath odordue toketones, andseizuresin advanced cases.Pregnancy toxemia appears to be most common in hot climates.Other serious complications during pregnancy can include aprolapsed uterus,hypocalcaemia, andmastitis.
Females that do not give birth may develop an irreversible fusing or calcified cartilage of thepubic symphysis, a joint in thepelvis, which may occur after six months of age.If they become pregnant after this has happened, the birth canal may not widen sufficiently, which may lead todystociaand death as they attempt to give birth.
Domestic guinea pigs generally live incages, although some owners of large numbers of cavies dedicate entire rooms to their pets.Wire mesh floors can cause injury and may be associated with an infection commonly known asbumblefoot(ulcerative pododermatitis),so cages with solid bottoms, where the animal walks directly on the bedding, are typically used. Large cages allow for adequate running space and can be constructed from wire grid panels and plastic sheeting, a style known as C&C, or "cubes and coroplast".
Red cedar (EasternorWestern) andpine, bothsoftwoods, were commonly used as bedding. Still, these materials are believed to contain harmfulphenols(aromatic hydrocarbons) and oils.Bedding materials made fromhardwoods(such asaspen), paper products, andcorn cobsare alternatives.Guinea pigs tend to be messy; they often jump into their food bowls or kick bedding and feces into them, and theirurinesometimes crystallizes on cage surfaces, making it difficult to remove.After its cage has been cleaned, a guinea pig typically urinates and drags its lower body across the floor of the cage tomark its territory.Male guinea pigs may mark their territory in this way when they are put back into their cages after being taken out.
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, but boars can sometimes live together. Guinea pigs learn to recognize and bond with other individual guinea pigs, and tests show that a boar'sneuroendocrinestress response to a strange environment is significantly lowered in the presence of a bonded female but not with unfamiliar females.Groups of boars may also get along, provided their cage has enough space, they are introduced at an early age, and no females are present.In Switzerland, where owning a single guinea pig is considered harmful to its well-being, keeping a guinea pig without a companion is illegal.There is a service to rent guinea pigs, to temporarily replace a dead cage-mate.Sweden has similar laws against keeping a guinea pig by itself.
The guinea pig's natural diet isgrass; theirmolarsare particularly suited for grinding plant matter and grow continuously throughout their life.Most mammals that graze are large and have a long digestive tract.  Guinea pigs have much longercolonsthan most rodents.
Easily digestible food is processed in the gastrointestinal tract and expelled as regular feces.  But to get nutrients out of hard-to-digest fiber, guinea pigs ferment fiber in the cecum (in the GI tract) and then expel the contents ascecotropes, which are reingested (cecotrophy).  The cecotropes are then absorbed in the small intestine to utilize the nutrients.Thececotropesare eaten directly from the anus unless the guinea pig is pregnant or obese.They share this behavior withlagomorphs(rabbits, hares, pikas) and some other animals.
In geriatric boars or sows (rarely in young ones), the muscles which allow the cecotropes to be expelled from the anus can become weak. This creates a condition known asfecal impaction, which prevents the animal from redigesting cecotropes even though harder pellets may pass through the impacted mass.The condition may be temporarily alleviated by a human carefully removing the impacted feces from the anus.
Guinea pigs benefit from a diet of freshgrass hay, such astimothy hay, in addition tofood pellets, which are often based on timothy hay.Alfalfahay is also a popular food choice, and most guinea pigs will eat large amounts of alfalfa when offered it,though some controversy exists over offering alfalfa to adult guinea pigs. Some pet owners and veterinary organizations have advised that, as alegumerather than a grass hay, alfalfa consumed in large amounts may lead toobesity, as well asbladder stonesfrom the excesscalciumin all animals except for pregnant and very young guinea pigs.However, published scientific sources mention alfalfa as a food source that can replenish protein,amino acids, and fiber.
Like humans, but unlike most othermammals, guinea pigs cannot synthesize vitamin C and must obtain this vitalnutrientfrom food. If guinea pigs do not ingest enough vitamin C, they can suffer from potentially fatalscurvy. They require about 10 mg of vitamin C daily (20 mg if pregnant), which can be obtained through fresh, raw fruits and vegetables (such as broccoli, apple, cabbage, carrot, celery, and spinach) or dietary supplements or by eating freshpelletsdesigned for guinea pigs, if they have been handled properly.Healthy diets for guinea pigs require a complex balance of calcium,magnesium,phosphorus,potassium, andhydrogen ions; but adequate amounts of vitaminsA,D, andEare also necessary.
Poor diets for guinea pigs have been associated withmuscular 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 after having learned early in life what is and is not appropriate to consume. Their eating habits may be difficult to change after maturity.They do not respond well to sudden changes in their diet, and they may stop eating and starve rather than accept new food types.A constant supply of hay is generally recommended, as guinea pigs feed continuously and may develop bad habits if food is not present, such as chewing on their hair.Being rodents, as their teeth grow constantly (as do their nails, like humans), they routinelygnawon things, lest their teeth become too large for their jaw (a common problem inrodents).Guinea pigs chew on cloth, paper, plastic, and rubber if available. Guinea pig owners may "Guinea Pig proof" their household, especially if they are free to roam, to avoid any destruction or harm to the guinea pig itself.
Some plants are poisonous to guinea pigs, includingbracken,bryony,buttercup,charlock,deadly nightshade,foxglove,hellebore,hemlock,lily of the valley,mayweed,monkshood,privet,ragwort,rhubarb,speedwell, toadflax (bothLinaria vulgarisandLinaria dalmatica), andwild celery.Additionally, any plant which grows from abulb(e.g.,tuliporonion) is normally considered poisonous,as well as ivy and oak tree leaves.
Common ailments in domestic guinea pigs includerespiratory tract infections,diarrhea,scurvy(vitamin C deficiency, typically characterized by sluggishness),abscessesdue to infection (often in the neck, due to hay embedded in the throat, or from external scratches), and infections bylice,mites, orfungus.
Mange mites(Trixacarus caviae) are a common cause of hair loss, and other symptoms may also include excessive scratching, unusually aggressive behavior when touched (due to pain), and, in some instances, seizures.Guinea pigs may also suffer from "running lice" (Gliricola porcelli), a small, white insect that can be seen moving through the hair; their eggs, which appear as black or white specks attached to the hair, are sometimes referred to as "static lice". Other causes of hair loss can be hormonal upsets caused by underlying medical conditions such asovarian cysts.
Foreign bodies, especially tiny pieces of hay or straw, can become lodged in the eyes of guinea pigs, resulting in excessive blinking, tearing, and, in some cases, an opaque film over the eye due tocorneal ulcer.Hay or straw dust can also causesneezing. While it is normal for guinea pigs to sneeze periodically, frequent sneezing may be a symptom ofpneumonia, especially in response to atmospheric changes. Pneumonia may also be accompanied bytorticollisand can be fatal.
Because the guinea pig has a stout, compact body, it more easily tolerates excessive cold than excessive heat.Its normalbody temperatureis 38–40 °C (101–104 °F),so its ideal ambient air temperature range is similar to a human's, about 18–24 °C (65–75 °F).Consistent ambient temperatures in excess of 32 °C (90 °F) have been linked tohyperthermiaand death, especially among pregnant sows.Guinea pigs are not well suited to environments that feature wind or frequent drafts,and respond poorly to extremes ofhumidityoutside of the range of 30–70%.
Guinea pigs arepreyanimals whose survival instinct is to mask pain and signs of illness, and many times, health problems may not be apparent until a condition is severe or in its advanced stages. Treatment of disease is made more difficult by the extreme sensitivity guinea pigs have to mostantibiotics, includingpenicillin, which kill off theintestinal floraand quickly bring on episodes of diarrhea and in some cases, death.
Similar to the inheritedgenetic diseasesof other breeds of animals (such aship dysplasiain canines), some genetic abnormalities of guinea pigs have been reported. Most commonly, theroancoloration ofAbyssinianguinea pigs is associated withcongenitaleye disorders and problems with the digestive system.Other genetic disorders include "waltzing disease" (deafness coupled with a tendency to run in circles), palsy, andtremorconditions.
If handled correctly early in life, guinea pigs become amenable to being picked up and carried and seldom bite or scratch.They are timid explorers who often hesitate to escape their cage even when an opportunity presents itself.Still, they show considerable curiosity when allowed to walk freely, especially in familiar and safe terrain. Guinea pigs that 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 opening of refrigerator doors, where their food is most commonly stored.
Domesticated guinea pigs occur in many breeds that have developed since their introduction to Europe and North America. These varieties vary in hair and color composition. The most common variety found in pet stores is the English shorthair (also known as the American), which has a short, smooth coat, and theAbyssinian, whose coat is ruffled withcowlicks, orrosettes. Also popular among breeders are thePeruvianand theSheltie(or Silkie), both straight longhair breeds, and theTexel, a curly longhair. Grooming of guinea pigs is primarily accomplished using combs or brushes. Shorthair breeds are typically brushed weekly, while longhair breeds may require daily grooming.
Cavy clubs and associations dedicated to the showing and breeding guinea pigs have been established worldwide. The American Cavy Breeders Association, an adjunct to theAmerican Rabbit Breeders' Association, is the governing body in the United States and Canada.TheBritish Cavy Councilgoverns cavy clubs in the United Kingdom. Similar organizations exist in Australia (Australian National Cavy Council)and New Zealand (New Zealand Cavy Council).Each club publishes its standard of perfection and determines which breeds are eligible for showing.
Allergicsymptoms, includingrhinitis,conjunctivitis, andasthma, have been documented in laboratory animal workers who come into contact with guinea pigs.Allergic reactions following direct exposure to guinea pigs in domestic settings have also been reported.Two major guinea pig allergens, Cav p I and Cav p II, have been identified in guinea pig fluids (urine and saliva) and guinea pigdander.People who are allergic to guinea pigs are usually allergic to hamsters and gerbils, as well.Allergy shotscan successfully treat an allergy to guinea pigs. However, treatment can take up to 18 months.
Folklore traditions involving guinea pigs are numerous; they are exchanged as gifts, used in customary social and religious ceremonies, and frequently referred to in spoken metaphors.They also are used in traditional healing rituals by folk doctors, orcuranderos, who use the animals to diagnose diseases such asjaundice,rheumatism,arthritis, andtyphus.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 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 unavailable or distrusted.
Peruvians consume an estimated 65 million guinea pigs each year. The animal is so entrenched in the culture that one famous painting of theLast Supperin themain cathedral in CuscoshowsChristand his disciples dining on guinea pig.The animal remains an important aspect of certain religious events in both rural and urban areas of Peru. A religious celebration, known asjaca tsariy("collecting the cuys"), is a major festival in many villages in theAntonio Raimondiprovince of eastern Peru and is celebrated in smaller ceremonies inLima.It is asyncretisticevent, combining elements ofCatholicismandpre-Columbianreligious practices, and revolves around the celebration of localpatron saints.The exact form thejaca tsariytakes differs from town to town; in some localities, asirvinti(servant) is appointed to go from door to door, collecting donations of guinea pigs, while in others, guinea pigs may be brought to a communal area to be released in a mockbullfight.Meals such ascuy chactadoare always served as part of these festivities, and the killing and serving of the animal are framed by some communities as a symbolicsatireof local politicians or important figures.In theTungurahuaandCotopaxiprovinces of central Ecuador, guinea pigs are employed in the celebrations surrounding the feast ofCorpus Christias part of theEnsayo, which is a community meal, and theOctava, wherecastillos(greased poles) are erected with prizes tied to the crossbars, from which several guinea pigs may be hung.The Peruvian town ofChurinhas an annual festival that involves dressing guinea pigs in elaborate costumes for competition.There are also guinea pig festivals held inHuancayo,Cusco,Lima, andHuacho, featuring costumes and guinea pig dishes. Most guinea pig celebrations occur on National Guinea Pig Day (Día Nacional del Cuy) across Peru on the second Friday of October.
As a result of their widespread popularity, especially in households with children, guinea pigs have shown a presence in culture and media. Some noted appearances of the animal inliteratureinclude the short story "Pigs Is Pigs" byEllis Parker Butler, which is a tale ofbureaucraticincompetence. Two guinea pigs held at a railway station breed unchecked while humans argue whether they are "pigs" or "pets" to determine freight charges.Butler's story, in turn, inspired theStar Trek: The Original Seriesepisode "The Trouble with Tribbles", written byDavid Gerrold.
The Fairy Caravan, a novel byBeatrix Potter,andMichael Bond'sOlga da Polgaseries for children,both feature guinea pigs as theprotagonist. Another appearance is inThe Magician's NephewbyC. S. Lewis: in the first (chronologically) of hisThe Chronicles of Narniaseries, a guinea pig is the first creature to travel to theWood between the Worlds.InUrsula Dubosarsky'sMaisie and the Pinny Gig, a little girl has a recurrent dream about a giant guinea pig, while guinea pigs feature significantly in several of Dubosarsky's other books, including the young adult novelThe White Guinea PigandThe Game of the Goose.
Guinea pigs have also been featured in film and television. In the TV movieShredderman Rules, the main character and the main character's crush both have guinea pigs, which play a minor part in the plot. A guinea pig named Rodney, voiced byChris Rock, was a prominent character in the 1998 filmDr. Dolittle, and Linny the Guinea Pig is a co-star onNick Jr.'sWonder Pets. Guinea pigs were used in some majoradvertising campaignsin the 1990s and 2000s, notably forEgg Banking plc,Snapple, andBlockbuster Video.In theSouth Parkseason 12episode "Pandemic 2: The Startling", giant guinea pigs dressed in costumes rampage over the Earth.The 2009Walt Disney PicturesmovieG-Forcefeatures a group of highly intelligent guinea pigs trained as operatives of the U.S. government.
Guinea pigs (calledcuy,cuye, orcurí) were originally domesticated for their meat in the Andes. Traditionally, the animal was reserved for ceremonial meals and as adelicacyby indigenous people in the Andean highlands. Still, since the 1960s, it has become more socially acceptable for consumption by all people.It continues to be a significant part of the diet in Peru and Bolivia, particularly in the Andes Mountains highlands; it is also eaten in some areas of Ecuador (mainly in theSierra) and in Colombia,mainly in the southwestern part of the country (CaucaandNariñodepartments). Because guinea pigs require much less room than traditionallivestockand reproduce extremely quickly, they are a more profitable source of food and income than many traditional stock animals, such as pigs and cattle;moreover, they can be raised in an urban environment. Both rural and urban families raise guinea pigs for supplementary income, and the animals are commonly bought and sold at local markets and large-scale municipal fairs.
Guinea pig meat is high inproteinand low infatandcholesterol, and is described as being similar to rabbit and the dark meat ofchicken.The animal may be served fried (chactadoorfrito), broiled (asado), or roasted (al horno), and in urban restaurants may also be served in acasseroleor africassee.Ecuadorians commonly consumesopaorlocro de cuy, a soup dish.Pachamancaorhuatia, anearth ovencooking method, is also popular, and cuy cooked this way is usually served withchicha(corn beer) in traditional settings.
Andean immigrants in New York City raise and sell guinea pigs for meat, and some South American restaurants in major cities in the United States servecuyas a delicacy.In the 1990s and 2000s, La Molina University began exporting large-breed guinea pigs to Europe, Japan, and the United States in the hope of increasing human consumption outside of countries in northern South America.
Efforts have been made to promote guinea pighusbandryin developing countries ofWest Africa,where they occur more widely than generally known because they are usually not covered by livestock statistics. However, it has not been known when and where the animals have been introduced to Africa.InCameroon, they are widely distributed.In theDemocratic Republic of the Congo, they can be found both in peri-urban environmentsas well as in rural regions, for example, inSouth Kivu.They are also frequently held in rural households inIringa Regionof southwesternTanzania.
Peruvian research universities, especiallyLa Molina National Agrarian University, began experimental programs in the 1960s intending to breed larger-sized guinea pigs.Subsequent university efforts have sought to change breeding and husbandry procedures in South America to make the raising of guinea pigs as livestock more economically sustainable.The variety of guinea pig produced by La Molina is fast-growing and can weigh 3 kg (6.6 lb).All the large breeds of guinea pig are known ascuy mejoradosand the pet breeds are known ascuy criollos. The three original lines out of Peru were thePerú(weighing 800 g (28 oz) by 2 weeks), theAndina, and theInti.
The use of guinea pigs in scientific experimentation dates back at least to the 17th century, when the Italian biologistsMarcello MalpighiandCarlo Fracassaticonductedvivisectionsof guinea pigs in their examinations ofanatomicstructures.In 1780,Antoine Lavoisierused a guinea pig in his experiments with thecalorimeter, a device used to measure heat production.Guinea pigs played a major role in the establishment ofgerm theoryin the late 19th century, through the experiments ofLouis Pasteur,Émile Roux, andRobert Koch.Guinea pigs have beenlaunched into orbital space flightseveral times, first by theUSSRon theSputnik 9biosatelliteof March 9, 1961 – with a successful recovery.Chinaalso launched and recovered a biosatellite in 1990 which included guinea pigs as passengers.
Guinea pigs remained popular laboratory animals until the later 20th century: about 2.5 million guinea pigs were used annually in the U.S. for research in the 1960s,but that total decreased to about 375,000 by the mid-1990s.As of 2007, they constitute about 2% of the current total of laboratory animals.In the past, they were widely used to standardizevaccinesandantiviral agents; they were also often employed in studies on the production ofantibodiesin response to extremeallergic reactions, oranaphylaxis.Less common uses included research inpharmacologyandirradiation.Since the middle 20th century, they have been replaced in laboratory contexts primarily by mice and rats. This is in part because research into the genetics of guinea pigs has lagged behind that of other rodents, although geneticistsW. E. CastleandSewall Wrightmade some contributions to this area of study, especially regardingcoat color.The guinea piggenomewassequencedin 2008 as part of theMammalian Genome Project, but the guinea pig sequence scaffolds have not been assigned to chromosomes.
The guinea pig was most extensively used in research and diagnosis ofinfectious diseases.Common uses included identification ofbrucellosis,Chagas disease,cholera,diphtheria,foot-and-mouth disease,glanders,Q fever,Rocky Mountain spotted fever, and various strains oftyphus.They are still frequently used to diagnosetuberculosissince they are easily infected by human tuberculosis bacteria.Because guinea pigs are one of the few animals which, like humans and otherprimates, cannot synthesize vitamin C but must obtain it from their diet, they are ideal for researching scurvy.From the accidental discovery in 1907 that scurvy could be induced in guinea pigs to their use to prove the chemical structure of the "scorbutic factor" in 1932, the guinea pig model proved a crucial part of vitamin C research.
Complement, an important component forserology, was first isolated from the blood of the guinea pig.Guinea pigs have an unusual insulin mutation,and are a suitable species for the generation of anti-insulin antibodies.Present at a level 10 times that found in other mammals, the insulin in guinea pigs may be important in growth regulation, a role usually played bygrowth hormone.Additionally, guinea pigs have been identified asmodel organismsfor the study of juvenile diabetes and, because of the frequency of pregnancy toxemia, of pre-eclampsia in human females.Their placental structure is similar to that of humans, and their gestation period can be divided into trimesters that resemble the stages of fetal development in humans.
Guinea pigstrainsused in scientific research are primarily outbred strains. Aside from the typical American or English stock, the two main outbred strains in laboratory use are the Hartley and Dunkin-Hartley; these English strains arealbino, although pigmented strains are also available.Inbred strainsare less common and are usually used for very specific research, such as immune system molecular biology. Of the inbred strains that have been created, the two still used with any frequency are, following Sewall Wright's designations, "Strain 2" and "Strain 13".
Hairless breeds of guinea pigs have been used in scientific research since the 1980s, particularly fordermatologicalstudies. A hairless andimmunodeficientbreed was the result of a spontaneous genetic mutation in inbred laboratory strains from the Hartley stock at theEastman Kodak Companyin 1979.An immunocompetent hairless breed was also identified by theInstitute Armand Frappierin 1978, andCharles River Laboratorieshas reproduced this breed for research since 1982.Cavy fanciers then began acquiring hairless breeds, and the pet hairless varieties are referred to as "skinny pigs".
InEnglish, the term "guinea pig" is commonly used as a metaphor for a subject of scientific experimentation, or in modern times a subject of any experiment or test. This usage dates back to the early 20th century: the earliest examples cited by theOxford English Dictionarydate from 1913 and 1920.In 1933,Consumers' ResearchfoundersF. J. SchlinkandArthur Kalletwrote a book entitled100,000,000 Guinea Pigs, extending the metaphor to consumer society.The book became a national bestseller in the United States, thus further popularizing the term, and spurred the growth of theconsumer protectionmovement.DuringWorld War II, theGuinea Pig Clubwas established atQueen Victoria Hospital,East Grinstead, Sussex, England, as a social club and mutual support network for the patients ofplastic surgeonArchibald McIndoe, who were undergoing previously untested reconstruction procedures.The negative connotation of the term was later employed in the novelThe Guinea Pigs(1970) byCzechauthorLudvík Vaculíkas an allegory forSoviettotalitarianism.