The guinea pig (Cavia porcellus), also commonly called the cavy, 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 of a closely related species of cavy such as Cavia aperea, C. fulgida, or C. tschudii, and therefore do not exist naturally in the wild.^[1][2] 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.^[3] Since the 1960s, efforts have been made to increase consumption of the animal outside South America.^[4]

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.

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, resulting in the epithet “guinea pig” for a test subject, 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.

[edit] 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),^[5] some thousands of years after the domestication of the South American camelids.^[6] Statues dating from ca. 500 BC to 500 AD that depict guinea pigs have been unearthed in archaeological digs in Peru and Ecuador.^[7] The Moche people of ancient Peru worshipped animals and often depicted the guinea pig in their art.^[8] 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.^[9] They continue to be a food source in the region; many households in the Andean highlands raise the animal, which subsists off the family’s vegetable scraps.^[10] 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.^[11] 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.^[12] They are rubbed against the bodies of the sick, and are seen as a supernatural medium.^[13] Black guinea pigs are considered especially useful for diagnoses.^[14] The animal also may be cut open and its entrails examined to determine whether the cure was effective.^[15] These methods are widely accepted in many parts of the Andes, where Western medicine is either unavailable or distrusted.^[16]

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.^[5] 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 was likely introduced there by Spanish travelers.^[1] The guinea pig was first described in the West in 1554 by the Swiss naturalist Conrad Gessner.^[17] Its binomial scientific name was first used by Erxleben in 1777; it is an amalgam of Pallas‘ generic designation (1766) and Linnaeus‘ specific conferral (1758).^[1]

[edit] 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.^[18] Cabiai may be an adaptation of the Portuguese çavia (now savia), which is itself derived from the Tupi word saujá, meaning rat.^[19] Guinea pigs are called quwi or jaca in Quechua and cuy or cuyo (pl. cuyes, cuyos) in the Spanish of Ecuador, Peru, and Bolivia.^[20] Ironically, 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”.^[21]

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.^[22] They can survive for long periods in small quarters, like a ‘pig pen’, and were thus easily transported on ships to Europe.^[23]

The animal’s name carries porcine connotations in many European languages. The German word for them is Meerschweinchen, literally “little sea pig”, which has been translated into Polish as świnka morska, into Hungarian as tengerimalac and into Russian as морская свинка which can be translated to English as “sea pig”. 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. The French term is Cochon d’Inde (Indian pig) or cobaye; the Dutch call it Guinees biggetje (Guinean piglet) or cavia, (while in some Dutch dialects it is called Spaanse rat), and in Portuguese the guinea pig is variously referred to as cobaia, from the Tupi word via its Latinization, or 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).^[20] Equally peculiar, the Chinese refer to them as Holland pigs (荷蘭豬, hélánzhū).

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.^[21] “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.^[24][25] 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.^[24][26] 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.^[27] 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.^[21]

[edit] Traits and environment

Two parti-colored Abyssinian guinea pigs

Guinea pigs are large for rodents, weighing between 700 and 1200 g (1.5–2.5 pounds), and measuring between 20 and 25 cm (8–10 inches) in length.^[28] They typically live an average of four to five years, but may live as long as eight years.^[29] According to the 2006 Guinness Book of Records the longest living guinea pig survived 14 years, 10.5 months.^[30]

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).^[31][32] Subsequent research using wider sampling has restored consensus among mammalian biologists that the current classification of rodents as monophyletic is justified.^[33][34]

[edit] 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.^[1] 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.^[9] 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.^[35] 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.^[35] They are crepuscular, tending to be most active during dawn and dusk, when it is harder for predators to spot them.^[36]

[edit] 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.^[37] 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.^[38] 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.^[36] Activity is scattered randomly over the 24 hours of the day; aside from avoidance of intense light, no regular circadian patterns are apparent.^[36]

This cat has accepted this pair of guinea pigs. The success of this type of interspecies interaction varies according to the individual animals involved

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).^[39] “Cubes and Coroplast” (or C&C) style cages are now a common choice.^[40] Cages are often lined with wood shavings or a similar material. Bedding made from Red Cedar^{[disambiguation needed]} and pine, both softwoods, was commonly used in the past, however these materials are now believed to contain harmful phenols (aromatic hydrocarbons) and oils.^[41] Safer beddings include those made from hardwoods (such as aspen), paper products, and corn cob materials are other alternatives.^[41] 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 sometimes crystallizes on cage surfaces, making it difficult to remove.^[42] 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.^[43] 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,^[44] and such rodents may act aggressively toward the guinea pig.^[45] Larger animals may regard guinea pigs as prey, though some (such as dogs) can be trained to accept them.^[46] 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.^[46][47] However, as lagomorphs, rabbits have different nutritional requirements, and so the two species cannot be fed the same food.^[48] Rabbits may also harbor diseases (such as the respiratory infections Bordetella and Pasteurella), to which guinea pigs are susceptible.^[49] Even the dwarf rabbit is much stronger than the guinea pig and may cause intentional or inadvertent injury.^[50]

[edit] Behavior

Guinea pigs can learn complex paths to food, and can accurately remember a learned path for months. Their strongest problem solving strategy is motion.^[51] While guinea pigs can jump small obstacles, they are poor climbers, 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.^[36] Larger groups of startled guinea pigs will “stampede”, running in haphazard directions as a means of confusing predators.^[52] When excited, guinea pigs may repeatedly perform little hops in the air (known as “popcorning”), a movement analogous to the ferret’s war dance.^[53] They are also exceedingly good swimmers.^[54]

Guinea pigs “social groom”

Like many rodents, guinea pigs sometimes participate in social grooming, and they regularly self-groom.^[55] A milky-white substance is secreted from their eyes and rubbed into the hair during the grooming process.^[56] Groups of boars will often chew each other’s hair, but this is a method of establishing hierarchy within a group, rather than a social gesture.^[54] Dominance is also established through biting (especially of the ears), piloerection, aggressive noises, head thrusts, and leaping attacks.^[57] Non-sexual simulated mounting for dominance is also common among same-sex groups.

Guinea pig sight is not as good as a human, but they have a wider range of vision (about 340°)^[58] and see in partial color (dichromacy). They have well-developed senses of hearing, smell, and touch.^[59] Vocalization is the primary means of communication between members of the species.^[60] Some sounds are:^[61][62]

• Wheek – A loud noise, the name of which is onomatopoeic, also known as a Whistle. An expression of general excitement, it may occur in response to the presence of its owner or to feeding. It is sometimes used to find other guinea pigs if they are running. If a guinea pig is lost, it may wheek for assistance. listen (help·info)
• Bubbling or Purring – This sound is made when the guinea pig is enjoying itself, such as when being petted or held. They may also make this sound when grooming, crawling around to investigate a new place, or when given food. listen (help·info)
• Rumbling – This sound is normally related to dominance within a group, though it can also come as a response being scared or angry. In these cases the rumble often sounds higher and the body vibrates shortly. While courting, a male usually purrs deeply, swaying and circling the female^[63] in a behavior called “rumblestrutting”. A low rumble while walking away reluctantly shows passive resistance. listen (help·info)
• Chutting and Whining – These are sounds made in pursuit situations, by the pursuer and pursuee, respectively. listen (help·info)
• Chattering – This sound is made by rapidly gnashing the teeth, and is generally a sign of warning. Guinea pigs tend to raise their heads when making this sound. A more relaxed type of gnashing often means the guinea pig wants a treat that is somewhere nearby but out of reach.^{[original research?]}
• Squealing or Shrieking – A high-pitched sound of discontent, in response to pain or danger. listen (help·info)
• Chirping – This less-common sound, likened to bird song, seems to be related to stress, or when a baby guinea pig wants to be fed. Very rarely, the chirping will last for several minutes. listen (help·info)

[edit] Breeding

Pregnant sow one week before delivering three pups

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.^[9] The gestation period lasts from 59–72 days, with an average of 63–68 days.^[43] 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. Unlike the offspring of most other rodents, which are altricial at birth, newborn pups are well-developed with hair, teeth, claws, and partial eyesight;^[54] 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;^[29] the largest recorded litter size is 17.^[64]

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.^[65] Cohabitating females assist in mothering duties if lactating.^[66]

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.^[67] The male’s testes may also be visible externally from scrotal swelling.

Guinea pig pup at eight hours old

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.^[68] Females that have never given birth commonly develop irreversible fusing of the pubic symphysis, a joint in the pelvis, after six months of age.^[43] 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.^[69] Females can become pregnant 6–48 hours after giving birth, but it is not healthy for a female to be thus constantly pregnant.^[70]

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.^[71] Pregnancy toxemia appears to be most common in hot climates.^[72] Other serious complications of pregnancy can include a prolapsed uterus, hypocalcaemia, and mastitis.^[73]

[edit] Diet

A silver agouti guinea pig eating grass

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.^[74] 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.^[75] However, they do not consume all their feces indiscriminately, but produce special soft pellets, called cecotropes, which recycle B vitamins, fiber, and bacteria required for proper digestion.^[76] The cecotropes (or caecal pellets) are eaten directly from the anus, unless the guinea pig is pregnant or obese.^[48] They share this behaviour with rabbits. In geriatric boars or sows (the condition is rarer in young ones), the muscles which allow the softer pellets to be expelled from the anus for consumption can become weak. This creates a condition known as anal impaction, which prevents the boar from redigesting cecotropes, though harder pellets may pass through the impacted mass.^[77] The condition may be temporarily alleviated by carefully expelling the impacted 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,^[78] 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.^[79][80] However, published scientific sources mention alfalfa as a source for replenishment of protein, amino acids, and fiber.^[81][82]

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.^[83] 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.^[84] Imbalanced diets have been associated with muscular dystrophy, metastatic calcification, difficulties with pregnancy, vitamin deficiencies, and teeth problems.^[85] 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.^[86] They do not respond well to sudden changes in diet; they may stop eating and starve rather than accepting new food types.^[54] A constant supply of hay or other food is generally recommended, as guinea pigs feed continuously and may develop habits such as chewing on their own hair if food is not present.^[87] Because guinea pigs’ teeth grow constantly, they routinely gnaw, lest their teeth become too large for their mouth, a common problem in rodents.^[40] Guinea pigs will also chew on cloth, paper, plastic, and rubber.

A number of plants are poisonous to guinea pigs, including bracken, bryony, buttercup, charlock, deadly nightshade, foxglove, hellebore, hemlock, Lily of the Valley, mayweed^{[disambiguation needed]}, monkshood, privet, ragwort, rhubarb, speedwell, toadflax^{[disambiguation needed]}, and wild celery.^[88] Additionally, any plant which grows from a bulb (e.g., tulip and onion) is normally considered poisonous.^[88]

[edit] Health

A parti-colored guinea pig suffering from Torticollis, or wry neck

Common ailments in domestic guinea pigs include respiratory tract infections^{[disambiguation needed]}, 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.^[89]

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.^[90] Guinea pigs may also suffer from “running lice” (Gliricola porcelli), a small white insect which can be seen moving through the hair; the eggs of these lice, 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 due to hormonal upsets caused by underlying medical conditions such as ovarian cysts.^[91]

Foreign bodies, especially small 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 to corneal ulcer.^[92] Hay or straw dust can also cause sneezing. While it is normal for guinea pigs to sneeze periodically, frequent sneezing may be a symptom of pneumonia, especially in response to atmospheric changes. Pneumonia may also be accompanied by torticollis and can be fatal.^[93]

Because the guinea pig has a stout, compact body, the animal more easily tolerates excessive cold than excessive heat.^[94] Its normal body temperature is 101–104 °F (38–40 °C),^[95] and so its ideal ambient air temperature range is similar to the human’s, about 65–75 °F (18–24 °C).^[94] Consistent ambient temperatures in excess of 90 °F (32 °C) have been linked to hyperthermia and death, especially among pregnant sows.^[94] Guinea pigs are not well suited to environments that feature wind or frequent drafts,^[96] and respond poorly to extremes of humidity outside of the range of 30–70%.^[97]

Guinea pigs are prey animals 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 most antibiotics, including penicillin, which kill off the intestinal flora and quickly bring on episodes of diarrhea and in some cases, death.^[98]

Similar to the inherited genetic diseases of other breeds of animal (such as hip dysplasia in canines), a number of genetic abnormalities of guinea pigs have been reported. Most commonly, the roan coloration of Abyssinian guinea pigs is associated with congenital eye disorders and problems with the digestive system.^[99] Other genetic disorders include “waltzing disease” (deafness coupled with a tendency to run in circles), palsy, and tremor conditions.^[100]

[edit] Pets

A guinea pig being held

If handled correctly early in their life, guinea pigs become amenable to being picked up and carried, and seldom bite or scratch.^[54] They are timid explorers, and rarely attempt to escape from their cages, even when an opportunity presents itself.^[47] Guinea pigs 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 opening of refrigerator doors, where their food is most commonly stored.

Guinea pigs should be kept in pairs or, preferably groups, unless there is a specific medical condition that requires isolation. Lone guinea pigs are more likely to suffer from stress and depression^[101]; for this reason, it is illegal in Sweden to sell a lone guinea pig to a buyer who does not have any other guinea pigs^[102]. It is a common misconception that male guinea pigs cannot be kept in groups; male guinea pigs can make excellent companions, especially when introduced from a young age and, generally, aggression would only occur if there was limited space or resources or a higher ratio of males to females. Guinea pig compatibility relies more heavily on personality than on gender^[103].

Domesticated guinea pigs come in many breeds, which have been developed since their introduction to Europe and North America. These varieties vary in hair and color composition. The most common varieties found in pet stores are the English shorthair (also known as the American), which have a short, smooth coat, and the Abyssinian, whose coat is ruffled with cowlicks, or rosettes. Also popular among breeders are the Peruvian and the Sheltie (or Silkie), both straight longhair breeds, and the Texel, a curly longhair.

Cavy Clubs and Associations dedicated to the showing and breeding of guinea pigs have been established worldwide. The American Cavy Breeders Association, an adjunct to the American Rabbit Breeders’ Association, is the governing body in the United States and Canada.^[104] The British Cavy Council governs cavy clubs in the United Kingdom. Similar organizations exist in Australia (Australian National Cavy Council)^[105] and New Zealand (New Zealand Cavy Club).^[106] Each club publishes its own Standard of Perfection and determines which breeds are eligible for showing.

[edit] Cultural and media influence

A lilac, orange and white Satin Peruvian guinea pig (show-length coat)

As a result of their widespread popularity in human domestic life, and especially because of their popularity in households with children, guinea pigs have shown a presence in culture and media. Some noted appearances of the animal in literature are The Fairy Caravan, a novel by Beatrix Potter,^[107] and Michael Bond‘s Olga da Polga series for children,^[108] both of which feature guinea pigs as the central protagonist. Another appearance is in The Magician’s Nephew by C. S. Lewis: in the first (chronologically) of his The Chronicles of Narnia series, a guinea pig is the first creature to travel to the Wood between the Worlds.^[109] The short story Pigs Is Pigs by Ellis Parker Butler is a tale of bureaucratic incompetence; two guinea pigs held at a train station breed unchecked while humans argue as to whether they are “pigs” for the purpose of determining freight charges.^[110] Butler’s story, in turn, inspired the Star Trek: The Original Series episode “The Trouble with Tribbles“, written by David Gerrold.^[111] In the Golden Hamster Saga books, there are two guinea pigs named Enrico and Caruso who are modern-day thespians (named after Enrico Caruso) who serve as secondary characters, and often irritate the main character, Freddy Auratus who strongly dislikes their acting antics.

Guinea pigs have also been featured in film and television. In the TV movie Shredderman Rules, the main character and the main character’s crush both have guinea pigs which both play a minor part in the plot. A guinea pig named Rodney, voiced by Chris Rock, was a prominent character in the 1998 film Dr. Dolittle and Linny the Guinea pig is a co-star on Nick Jr.‘s Wonder Pets. Guinea pigs were used in some major advertising campaigns in the 1990s and 2000s, notably for Egg Banking plc,^[112] Snapple, and Blockbuster Video.^[113] The Blockbuster campaign is considered by some guinea pig advocates to have been a factor in the rise of caging guinea pigs and rabbits together.^[50] In the South Park season 12 episode “Pandemic 2: The Startling“,giant guinea pigs dressed in costumes, are portrayed as rampaging over the entire Earth^[114] The Walt Disney Pictures movie G-Force, released in the United States on July 24, 2009, features a group of highly intelligent guinea pigs trained as operatives of the U.S. government. A highly popular video game, based on the movie, was also released.

[edit] Scientific research

A guinea pig being examined by a veterinary medical officer for general health and pulmonary condition

The use of guinea pigs in scientific experimentation dates back at least to the 17th century, when the Italian biologists Marcello Malpighi and Carlo Fracassati conducted vivisections of guinea pigs in their examinations of anatomic structures.^[115] In 1780, Antoine Lavoisier used a guinea pig in his experiments with the calorimeter, a device used to measure heat production. The heat from the guinea pig’s respiration melted snow surrounding the calorimeter, showing that respiratory gas exchange is a combustion, similar to a candle burning.^[116] Guinea pigs played a major role in the establishment of germ theory in the late 19th century, through the experiments of Louis Pasteur, Émile Roux, and Robert Koch.^[117] Guinea pigs have been launched into orbital space-flight several times, first by the USSR on the Sputnik 9 biosatellite of March 9, 1961 – with a successful recovery.^[118] China also launched and recovered a biosatellite in 1990 which included guinea pigs as passengers.^[119]

Guinea pig being injected to test a chemical for its carcinogenic properties

In English, the term guinea pig is commonly used as a metaphor for a subject of scientific experimentation, or any experiment or test in modern times. This dates back to the early 20th century; the Oxford English Dictionary notes its first usage in this capacity in 1913.^[120] In 1933, Consumers Research founders F. J. Schlink and Arthur Kallet wrote a book entitled 100,000,000 Guinea Pigs, extending the metaphor to consumer society.^[121] The book became a national bestseller in the United States, thus further popularizing the term, and spurred the growth of the consumer protection movement.^[122] The negative connotation of the term was later employed in the novel The Guinea Pigs by Czech author Ludvík Vaculík as an allegory for Soviet totalitarianism.^[123]

Guinea pigs were 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,^[124] but that total decreased to about 375,000 by the mid-1990s.^[54] As of 2007, they constitute approximately 2% of the current total of laboratory animals.^[124] In the past they were widely used to standardize vaccines and antiviral agents; they were also often employed in studies on the production of antibodies in response to extreme allergic reactions, or anaphylaxis.^[125] Less common uses included research in pharmacology and irradiation.^[125] 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 geneticists W. E. Castle and Sewall Wright made a number of contributions to this area of study, especially regarding coat color.^[100][126] In 2004, the U.S.’s National Human Genome Research Institute announced plans to sequence the genome of the domestic guinea pig.^[127]

The guinea pig was most extensively implemented in research and diagnosis of infectious diseases.^[125] Common uses included identification of brucellosis, Chagas disease, cholera, diphtheria, foot-and-mouth disease, glanders, Q fever, Rocky Mountain spotted fever, and various strains of typhus.^[125] They are still frequently used to diagnose tuberculosis, since they are easily infected by human tuberculosis bacteria.^[124] Because guinea pigs are one of the few animals which, like humans, cannot synthesize vitamin C but must obtain it from their diet, they are ideal for researching scurvy.^[124] From the accidental discovery in 1907 that scurvy could be induced in guinea pigs, to their use to prove the chemical structure of the “ascorbutic factor” in 1932, the guinea pig model proved a crucial part of vitamin C research.^[128][129]

Complement, an important component for serology, was first isolated from the blood of the guinea pig.^[124] Guinea pigs have an unusual insulin mutation,^[130] and are a suitable species for the generation of anti-insulin antibodies.^[131] 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 by growth hormone.^[132] Additionally, guinea pigs have been identified as model organisms for the study of juvenile diabetes and, because of the frequency of pregnancy toxemia, of pre-eclampsia in human females.^[66]

Guinea pig strains used in scientific research are primarily outbred strains. Aside from the common American or English stock, the two main outbred strains in laboratory use are the Hartley and Dunkin-Hartley; these English strains are albino, although pigmented strains are also available.^[133] Inbred strains are 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 that are still used with any frequency are, following Sewall Wright’s designations, “Strain 2″ and “Strain 13″.^[100][133]

Hairless breeds of guinea pigs have been used in scientific research since the 1980s, particularly for dermatological studies. A hairless and immunodeficient breed was the result of a spontaneous genetic mutation in inbred laboratory strains from the Hartley stock at the Eastman Kodak Company in 1979.^[134] An immunocompetent hairless breed was also identified by the Institute Armand Frappier in 1978, and Charles River Laboratories has reproduced this breed for research since 1982.^[135] Cavy fanciers then began acquiring hairless breeds, and the pet hairless varieties are referred to as “skinny pigs“.

[edit] As food

Two Peruvian dishes of cuy meat

Guinea pigs (called cuy, cuye, curí) were originally domesticated for their meat in the Andes. Traditionally, the animal was usually reserved for ceremonial meals by indigenous people in the Andean highlands, but since the 1960s it has become more socially acceptable for consumption by all people.^[136] It continues to be a major 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 the Sierra) and Colombia.^[137] Because guinea pigs require much less room than traditional livestock and reproduce extremely quickly, they are a more profitable source of food and income than many traditional stock animals, such as pigs and cows;^[138] 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.^[139] Guinea pig meat is high in protein and low in fat and cholesterol, and is described as being similar to rabbit and the dark meat of chicken.^[4][140] The animal may be served fried (chactado or frito), broiled (asado), or roasted (al horno), and in urban restaurants may also be served in a casserole or a fricassee.^[141] Ecuadorians commonly consume sopa or locro de cuy, a soup dish.^[141] Pachamanca or huatia, a process similar to barbecueing, is also popular, and is usually served with corn beer (chicha) in traditional settings.^[141]

Cuy being raised at home in the traditional Andean fashion

Peruvians consume an estimated 65 million guinea pigs each year, and the animal is so entrenched in the culture that one famous painting of the Last Supper in the main cathedral in Cusco shows Christ and the twelve disciples dining on guinea pig.^[4] The animal remains an important aspect of certain religious events in both rural and urban areas of Peru. A religious celebration known as jaca tsariy (“collecting the cuys”) is a major festival in many villages in the Antonio Raimondi province of eastern Peru, and is celebrated in smaller ceremonies in Lima.^[142] It is a syncretistic event, combining elements of Catholicism and pre-Columbian religious practices, and revolves around the celebration of local patron saints.^[142] The exact form that the jaca tsariy takes differs from town to town; in some localities, a sirvinti (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 mock bullfight.^[142] Meals such as cuy chactado are always served as part of these festivities, and the killing and serving of the animal is framed by some communities as a symbolic satire of local politicians or important figures.^[142] In the Tungurahua and Cotopaxi provinces of central Ecuador, guinea pigs are employed in the celebrations surrounding the feast of Corpus Christi as part of the Ensayo, which is a community meal, and the Octava, where castillos (greased poles) are erected with prizes tied to the crossbars, from which several guinea pigs may be hung.^[143] The Peruvian town of Churin has an annual festival which involves dressing guinea pigs in elaborate costumes for a competition.^[144]

Andean immigrants in New York City raise and sell guinea pigs for meat, and some ethnic restaurants in major United States cities serve cuy as a delicacy.^[145] Peruvian research universities, especially La Molina National Agrarian University, began experimental programs in the 1960s with the intention of breeding larger-sized guinea pigs.^[146] Subsequent university efforts have sought to change breeding and husbandry procedures in South America, in order to make the raising of guinea pigs as livestock more economically sustainable.^[147] In the 1990s and 2000s, the university began exporting the larger breed guinea pigs to Europe, Japan, and the United States in the hope of increasing human consumption outside of these countries in northern South America.^[4] Efforts have also been made to introduce guinea pig husbandry in developing countries in West Africa.^[138] Nevertheless, as a food source they are still generally considered taboo in other countries in America and Europe; in reality television, guinea pig meat has been consumed as an exotic dish by such Western celebrity chefs as Andrew Zimmern (for his show Bizarre Foods) and Anthony Bourdain in No Reservations.

[edit] See also

Mammals portal

• British Cavy Council
• Peter Gurney
• Save the Newchurch Guinea Pigs

[edit] Footnotes

[edit] References

[edit] External links

Look up guinea pig in Wiktionary, the free dictionary.

Wikimedia Commons has media related to: Cavia porcellus

Wikispecies has information related to: Cavia porcellus

Wikibooks has a book on the topic of Animal Care/Guinea pig

• ACBA – American Cavy Breeders’ Association
• Laboratory Guinea Pig
• Domestic Guinea Pig Genome

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The Labrador Retriever (also Labrador, or Lab for short) is one of several kinds of retriever, a type of gun dog. A breed characteristic is webbed paws for swimming, useful for the breed’s original purpose of retrieving fishing nets. This and their subsequent use as hunting companions, gave them the name retriever. The dogs of this breed are very loving, kind and compassionate to their masters. The Labrador is the most popular breed of dog (by registered ownership) in the world, and is, by a large margin, the most popular breed by registration in Canada, the United States (since 1991),^[2] and the United Kingdom.^[3] It is also the most popular breed of assistance dog in Canada, the United States, Australia, United Kingdom and many other countries,^{[citation needed]} as well as being widely used by police and other official bodies for their detection and working abilities. Typically, Labradors are athletic, and love to swim, play catch and retrieve games, and are good with young children.^[4]

[edit] History

Nell – A St. John’s Dog circa 1856.

The modern Labrador’s ancestors originated on the island of Newfoundland, now part of the province of Newfoundland and Labrador, Canada.^[5] The breed emerged over time from the St. John’s Water Dog, (also a founding breed of the Newfoundland dog) through ad-hoc breedings by early settlers in the mid to late 16th century.^[5] The forebears of the St. John’s Dog are not known, but were likely a random-bred mix of English, Irish, and Portuguese working breeds. The Newfoundland (known then as the Greater Newfoundland) is likely a result of the St. John’s Dog breeding with mastiffs brought to the island by the generations of Portuguese fishermen who had been fishing offshore since the 1600s. The smaller short-coat St. John’s Dog (also known as the Lesser Newfoundland) was used for retrieval and pulling in nets from the water. These smaller dogs were the forebears of the Labrador Retriever. The white chest, feet, chin, and muzzle – known as tuxedo markings – characteristic of the St. John’s Dog often appear in Lab mixes, and will occasionally manifest in Labs as a small white spot on the chest (known as a medallion) or stray white hairs on the feet or muzzle..

The St. John’s area of Newfoundland was settled mainly by the English and Irish. Local fishermen originally used the St. John’s dog to assist in carrying ropes between boats, towing dories, and helping to retrieve fishnets in the water. The Labrador’s loyalty and hard working behavior earned him a place on many a fisherman’s boat.^[6]

A number of these dogs were brought back to the Poole area of England in the early 1800s,^[5] then the hub of the Newfoundland fishing trade, by the gentry, and became prized as sporting and waterfowl hunting dogs.^[5] A few kennels breeding these grew up in England; at the same time a combination of sheep protection policy (Newfoundland) and rabies quarantine (England) led to their gradual demise in their country of origin.^[7]

A surviving picture of Buccleuch Avon (b.1885), a foundational dog of many modern Labrador lineages.

The first and second Earls of Malmesbury, who bred for duck shooting on his estate,^[8] and the 5th and 6th Dukes of Buccleuch, and youngest son Lord George William Montagu-Douglas-Scott,^[8] were instrumental in developing and establishing the modern Labrador breed in nineteenth century England. The dogs Avon (“Buccleuch Avon”) and Ned given by Malmesbury to assist the Duke of Buccleuch’s breeding program in the 1880s are considered the ancestors of many modern Labradors.^[9]

The first St. John’s Dog was said to be brought to England around 1820; however, the breed’s reputation had spread to England long before. There is a story that the Earl of Malmesbury saw a St. John’s Dog on a fishing boat and immediately made arrangements with traders to have some of these dogs exported to England. These ancestors of the first labradors so impressed the Earl with their skill and ability for retrieving anything within the water and on shore that he devoted his entire kennel to developing and stabilizing the breed.^[6]

[edit] Early descriptions

Several early descriptions of the St. John’s Water Dog exist. In 1822, explorer W.E. Cormack crossed the island of Newfoundland by foot. In his journal he wrote “The dogs are admirably trained as retrievers in fowling, and are otherwise useful…..The smooth or short haired dog is preferred because in frosty weather the long haired kind become encumbered with ice on coming out of the water.”^[10]

Another early report by a Colonel Hawker described the dog as “by far the best for any kind of shooting. He is generally black and no bigger than a Pointer, very fine in legs, with short, smooth hair and does not carry his tail so much curled as the other; is extremely quick, running, swimming and fighting….and their sense of smell is hardly to be credited….”^[10]

In his book Excursions In and About Newfoundland During the Years 1839 and 1840,^[11] the geologist Joseph Beete Jukes describes the St. John’s Water Dog. “A thin, short-haired, black dog came off-shore to us to-day. The animal was of a breed very different from what we understand by the term Newfoundland dog in England. He had a thin, tapering snout, a long thin tail, and rather thin, but powerful legs, with a lank body, – the hair short and smooth.” wrote Jukes. “These are the most abundant dogs in the country…They are no means handsome, but are generally more intelligent and useful than the others…I observed he once or twice put his foot in the water and paddled it about. This foot was white, and Harvey said he did it to “toil” or entice the fish. The whole proceeding struck me as remarkable, more especially as they said he had never been taught anything of the kind.”

[edit] Name

The foundational breed of what is now the Labrador Retriever was known as the St. John’s Water Dog, St. John’s Dog, or Lesser Newfoundland. When the dogs were later brought to England, they were named after the geographic area known as “the Labrador” or simply Labrador to distinguish them from the larger Newfoundland breed, even though the breed was from the more southern Avalon Peninsula.

[edit] Historical landmarks

The first written reference to the breed was in 1814 (“Instructions to Young Sportsmen” by Colonel Peter Hawker),^[5] the first painting in 1823 (“Cora. A Labrador Bitch” by Edwin Landseer),^[5] and the first photograph in 1856 (the Earl of Home‘s dog “Nell”, described both as a Labrador and a St. Johns dog).^[7] By 1870 the name Labrador Retriever became common in England.^[5] The first yellow Labrador on record was born in 1899 (Ben of Hyde, kennels of Major C.J. Radclyffe),^[5] and the breed was recognised by the Kennel Club in 1903. The first American Kennel Club (AKC) registration was in 1917.^[5] The chocolate Labrador emerged in the 1930s,^[5] although liver spotted pups were documented being born at the Buccleuch kennels in 1892.^[5] The St. John’s dog survived until the early 1980s, the last two individuals being photographed in old age around 1981.^[7]

[edit] History of subtypes

Yellow and chocolate pups, would occasionally appear (although often culled), until finally gaining acceptance in the 20th century.

The first recognised yellow Labrador was Ben of Hyde, born 1899, and chocolate labs became more established in the 1930s.

Ben of Hyde (b.1899), the first recognised yellow Labrador.

Yellow (and related shades)

In the early years of the breed through to the mid-20th century, Labradors of a shade we would now call “yellow” were in fact a dark, almost butterscotch, colour (visible in early yellow Labrador photographs). The shade was known as “Golden” until required to be changed by the UK Kennel Club, on the grounds that “Gold” was not actually a colour. Over the 20th century a preference for far lighter shades of yellow through to cream prevailed, until today most yellow labs are of this shade.^[12]

Interest in the darker shades of gold and fox red were re-established by English breeders in the 1980s, and three dogs were instrumental in this change: Balrion King Frost (black, born approx. 1976) who consistently sired “very dark yellow” offspring and is credited as having “the biggest influence in the re-development of the fox red shade”,^[12] and his great-grandson, the likewise famous Wynfaul Tabasco (b.1986),^[13] described as “the father of the modern fox red Labrador”, and the only modern fox red Show Champion in the UK. Other dogs, such as Red Alert and Scrimshaw Placido Flamingo, are also credited with passing on the genes into more than one renowned bloodline.^[12]

Chocolate labradors

Jack Vanderwyk traces the origins of all Chocolate labradors listed on the LabradorNet database (some 34,000 Labrador dogs of all shades) to eight original bloodlines. However, the shade was not seen as a distinct colour until the 20th century; before then according to Vanderwyk, such dogs can be traced but were not registered. A degree of crossbreeding with Flatcoat or Chesapeake Bay retrievers was also documented in the early 20th century, prior to recognition. Chocolate labradors were also well established in the early 20th century at the kennels of the Earl of Feversham, and Lady Ward of Chiltonfoliat.^[14]

The bloodlines as traced by Vanderwyk each lead back to three black labradors in the 1880s—Buccleuch Avon (m), and his sire and dam, Malmesbury Tramp (m), and Malmesbury June (f). Morningtown Tobla is also named as an important intermediary, and according to the studbook of Buccleuch Kennels, the chocolates in that kennel came through FTW Peter of Faskally (1908).^[14]

[edit] Description

A black Labrador from English stock.

A Black Lab of American field stock

[edit] Appearance

Labradors are relatively large, with males typically weighing 29–41 kg (65-90 pounds) and females 25–32 kg (55–71 lb). Labs weighing close to or over 100 lbs are considered obese or having a major fault under American Kennel Club standards, although some labs weigh significantly more.^[15] The majority of the characteristics of this breed, with the exception of colour, are the result of breeding to produce a working retriever.

As with some other breeds, the Conformation (typically “English”, “show” or “bench”) and the Field (typically “American” or “working”) lines differ, although both lines are bred in both countries. In general, however, Conformation Labs tend to be bred as medium-sized dogs, shorter and stockier with fuller faces and a slightly calmer nature than their Field counterparts, which are often bred as taller, lighter-framed dogs, with slightly less broad faces and a slightly longer nose; however Field labs should still be proportional and fit within AKC standards. With field labs, excessively long noses, thin heads, long legs and lanky frames are not considered standard. These two types are informal and not codified or standardised; no distinction is made by the AKC or other kennel clubs, but the two types come from different breeding lines. Australian stock also exists; though not seen in the west, they are common in Asia.

The breed tends to shed hair twice annually, or regularly throughout the year in temperate climates.^[9] Some labs shed considerably; however, individual labs vary.^[16] Labrador hair is usually fairly short and straight, and the tail quite broad and strong. The otter-like tail and webbed toes of the Labrador Retriever make them excellent swimmers. The webbing between their toes can also serve as a “snowshoe” in colder climes and keep snow from balling up between their toes- a condition that can be painful to other breeds with hair between the toes. Their interwoven coat is also relatively waterproof, providing more assistance for swimming.

[edit] Official breed standards

There is a great deal of variety among Labs. The following characteristics are typical of the conformation show bred (bench-bred) lines of this breed in the United States, and are based on the AKC standard.^[15] Significant differences between US and UK standards are noted.

• Size: Labs are a medium-large but compact breed. They should have an appearance of proportionality. They should be as long from the withers to the base of the tail as they are from the floor to the withers. Males should stand 22.5–24.5 inches (57–62 cm) tall at the withers and weigh 65–80 lb (29–36 kg). Females should stand 21.5–23.5 inches (55–60 cm) and weigh 55–70 lb (25–32 kg). By comparison under UK Kennel Club standards, height should be 22–22.5 inches (56–57 cm) for males, and 21.5–22 inches (55–56 cm) for females.^[17]

• Coat: The Lab’s coat should be short and dense, but not wiry. The coat is described as ‘water-resistant’ or more accurately ‘water-repellent’ so that the dog does not get cold when taking to water in the winter. That means that the dog naturally has a slightly dry, oily coat. Acceptable colours are black, yellow (ranging fom ivory or creme to fox red), and chocolate.

• Head: The head should be broad with a pronounced stop and slightly pronounced brow. The eyes should be kind and expressive. Appropriate eye colours are brown and hazel. The lining around the eyes should be black. The ears should hang close to the head and are set slightly above the eyes.

• Jaws: The jaws should be strong and powerful. The muzzle should be of medium length, and should not be too tapered. The jaws should hang slightly and curve gracefully back.

• Body: The body should be strong and muscular with a level top line.

The tail and coat are designated “distinctive [or distinguishing] features” of the Labrador by both the Kennel Club and AKC.^[15][17] The AKC adds that “true Labrador Retriever temperament is as much a hallmark of the breed as the ‘otter’ tail.”^[15]

As well, Labradors should not have droopy eyes (like a Basset Hound). The skin should be relatively tight, and you should not be able to see the pinks on the inside of their lids.

[edit] Colour

Different shades of yellow: a usual yellow shade, and a fox red shade.

The three primary colour varieties of the Labrador Retriever

Labrador Retrievers are registered in three colours:^[15] black (a solid black colour), yellow (anything from light cream to “fox-red”), and chocolate (medium to dark brown). Some Labrador retrievers can have markings such as white patches on their chest and other areas, but most commonly they are one solid colour.

Puppies of all colours can potentially occur in the same litter. Colour is determined primarily by two genes. The first gene (the B locus) determines the density of the coat’s pigment granules: dense granules result in a black coat, sparse ones give a chocolate coat. The second (D) locus determines whether the pigment is produced at all. A dog with the recessive d allele will produce little pigment and will be yellow regardless of its genotype at the B locus.^[18] Variations in numerous other genes control the subtler details of the coat’s colouration, which in yellow Labs varies from white to light gold to a fox red. Chocolate and black Labs’ noses will match the coat colour.

[edit] Nose and skin pigmentation

Because Labrador colouration is controlled by multiple genes, it is possible for recessive genes to emerge some generations later and also there can sometimes be unexpected pigmentation effects to different parts of the body. Pigmentation effects appear in regard to yellow Labradors, and sometimes chocolate, and hence the majority of this section covers pigmentation within the yellow Labrador. The most common places where pigmentation is visible are the nose, lips, gums, feet, tail, and the rims of the eyes, which may be black, brown, light yellow-brown (“liver”, caused by having two genes for chocolate),^[19] or several other colours. A Labrador can carry genes for a different colour, for example a black Labrador can carry recessive chocolate and yellow genes, and a yellow Labrador can carry recessive genes for the other two colours. DNA testing can reveal some aspects of these. Less common pigmentations (other than pink) are a fault, not a disqualification, and hence such dogs are still permitted to be shown.^[19] The intensity of black pigment on yellow Labs is controlled by a separate gene independent of the fur colouring.^[19] Yellow Labradors usually have black noses, which may gradually turn pink with age (called “snow nose” or “winter nose”). This is due to a reduction in the enzyme tyrosinase which indirectly controls the production of melanin, a dark colouring. Tyrosinase is temperature dependent—hence light colouration can be seasonal, due to cold weather—and is less produced with increasing age two years old onwards. As a result, the nose colour of most yellow Labs becomes a somewhat pink shade as they grow older.^[19]

A seven-week-old Dudley Lab. The nose and lips are pink or flesh-coloured, the defining aspect of Dudley pigmentation.

A colouration known as “Dudley” is also possible. Dudleys are variously defined as yellow Labs which have unpigmented (pink) noses (LRC), yellow with liver/chocolate pigmentation (AKC), or “flesh coloured” in addition to having the same colour around the rims of the eye, rather than having black or dark brown pigmentation.^[9][19] A yellow Labrador with brown or chocolate pigmentation, for example, a brown or chocolate nose, is not necessarily a Dudley, though according to the AKC’s current standard it would be if it has chocolate rims around the eyes (or more accurately of the genotype eebb). Breed standards for Labradors considers a true Dudley to be a disqualifying feature in a conformation show Lab, such as one with a thoroughly pink nose or one lacking in any pigment along with flesh coloured rims around the eyes. True Dudleys are extremely rare.^[19][20]

Breeding in order to correct pigmentation often lacks dependability. Because colour is determined by many genes, some of which are recessive, crossbreeding a pigmentation non-standard yellow Labrador to a black Labrador may not correct the matter or prevent future generations carrying the same recessive genes. For similar reasons, crossbreeding chocolate to yellow labs is also often avoided.

[edit] Show and field lines

Chocolate Labradors from field-bred stock are typically lighter in build and have a shorter coat than conformation show Labrador.

There are significant differences between field and trial-bred (sometimes referred to as “American”) and show-bred (or “English”) lines of Labradors, arising as a result of specialised breeding. Dogs bred for hunting and field-trial work are selected first for working ability, where dogs bred to compete in conformation shows are selected for their conformation to the standards and characteristics sought by judges in the show ring.

Head and muzzle appearance: American or field (left), and English or show (right), showing the shorter muzzle length, more solid appearance head, and “pronounced” stop of the latter.

While individual dogs may vary, in general show-bred Labradors are heavier built, slightly shorter-bodied, and have a thicker coat and tail. Field Labradors are generally longer legged, lighter, and more lithe in build. In the head, show Labradors tend to have broader heads, better defined stops, and more powerful necks, while field Labradors have lighter and slightly narrower heads with longer muzzles.^[21][22] Field-bred Labradors are commonly higher energy and more high-strung compared to the Labrador bred for conformation showing, and as a consequence may be more suited to working relationships than being a “family pet“.^[21][22] Some breeders, especially those specialising in the field type, feel that breed shows do not adequately recognise their type of dog, leading to occasional debate regarding officially splitting the breed into subtypes.^[23]

In the United States, the AKC and the Labrador’s breed club have set the breed standard to accommodate the field-bred Labrador somewhat. For instance, the AKC withers-height standards allow conformation dogs to be slightly taller than the equivalent British standard.^[24] However, dual champions, or dogs that excel in both the field and the show ring, are becoming more unusual.^[25]

[edit] Temperament

A Labrador participating in dog agility

Labradors are a well-balanced, friendly and versatile breed, adaptable to a wide range of functions as well as making very good pets. As a rule they are not excessively prone to being territorial, pining, insecure, aggressive, destructive, hypersensitive, or other difficult traits which sometimes manifest in a variety of breeds. As the name suggests, they are excellent retrievers. Labradors instinctively enjoy holding objects and even hands or arms in their mouths, which they can do with great gentleness (a Labrador can carry an egg in its mouth without breaking it).^[26] They are also known to have a very soft feel to the mouth, as a result of being bred to retrieve game such as waterfowl. They are prone to chewing objects (though they can be trained out of this behavior). The Labrador Retriever’s coat repels water to some extent, thus facilitating the extensive use of the dog in waterfowl hunting.

Labradors enjoy playing with water

Labradors have a reputation as a very even-tempered breed and an excellent family dog (including a good reputation with children of all ages and other animals),^[9] but some lines (particularly those that have continued to be bred specifically for their skills at working in the field rather than for their appearance) are particularly fast and athletic. Their fun-loving boisterousness and lack of fear may require training and firm handling at times to ensure it does not get out of hand—an uncontrolled adult can be quite problematic. Females may be slightly more independent than males.^[9] Labradors mature at around three years of age; before this time they can have a significant degree of puppy-like energy, often mislabelled as being hyperactive.^[9][27] Because of their enthusiasm, leash-training early on is suggested to prevent pulling when full-grown.^[28] Labradors often enjoy retrieving a ball endlessly and other forms of activity (such as agility, frisbee, or flyball).

Although they will sometimes bark at noise, especially noise from an unseen source (“alarm barking“), Labs are usually not noisy^[9] or territorial. They are often very easygoing and trusting with strangers, and therefore are not usually suitable as guard dogs.^[9]

Labradors have a well-known reputation for appetite, and some individuals may be highly indiscriminate, eating digestible and non-food objects alike.^[26] They are persuasive and persistent in requesting food. For this reason, the Labrador owner must carefully control his/her dog’s food intake to avoid obesity and its associated health problems (see below).^[26]

The steady temperament of Labs and their ability to learn make them an ideal breed for search and rescue, detection, and therapy work. Their primary working role in the field continues to be that of a hunting retriever.

[edit] Exploration

A wet black Labrador exploring the beach.

They do not typically jump high fences or dig. Because of their personalities,(like swimming, playing, running, sleeping, and eating) some Labs climb and/or jump for their own amusement. As a breed they are highly intelligent and capable of intense single-mindedness and focus if motivated or their interest is caught. Therefore, with the right conditions and stimuli, a bored Labrador could “turn into an escape artist par excellence“.^[9][29]

Labradors as a breed are curious, exploratory and love company, following both people and interesting scents for food, attention and novelty value. In this way, they can often “vanish” or otherwise become separated from their owners with little fanfare.^[30] They are also popular dogs if found, and at times may be stolen.^[31] Because of this a number of dog clubs and rescue organisations (including the UK’s Kennel Club) consider it good practice that Labradors be microchipped, with the owner’s name and address also on their collar and tags.^[30][32]

[edit] Use as working dogs

Labradors are a very popular selection for use as guide dogs.

Labradors are an intelligent breed with a good work ethic and generally good temperaments (breed statistics show that 91.5% of Labradors who were tested passed the American Temperament Test.^[33]) Common working roles for Labradors include: hunting, tracking and detection (they have a great sense of smell which helps when working in these areas), disabled-assistance, carting, and therapy work.^[34] Approximately 60–70% of all guide dogs in Canada are Labradors; other common breeds are Golden Retrievers and German Shepherd Dogs.^[35]

The high intelligence, initiative and self-direction of Labradors in working roles is exemplified by dogs such as Endal, who during a 2001 emergency placed an unconscious human being in the recovery position, retrieved his mobile phone from beneath the car, fetched a blanket and covered him, barked at nearby dwellings for assistance, and then ran to a nearby hotel to obtain help.^[36] A number of labradors have also been taught to assist their owner in removing money and credit cards from ATMs with prior training.^[37]

[edit] Health

Many dogs, including Labs such as this twelve year old, show distinct whitening of the coat as they grow older; especially around the muzzle.

Labrador pups should not be brought home before they are 7–10 weeks old. Their life expectancy is generally 10 to 12 years,^[1] and it is a healthy breed with relatively few major problems. Notable issues related to health and well-being include:

[edit] Inherited disorders

• Labs are somewhat prone to hip and elbow dysplasia,^[38] especially the larger dogs,^[39] though not as much as some other breeds.^[40] Hip scores are recommended before breeding and often joint supplements are recommended.
• Labs also suffer from the risk of knee problems. A luxating patella is a common occurrence in the knee where the leg is often bow shaped.
• Eye problems are also possible in some Labs, particularly progressive retinal atrophy, cataracts,^[41] corneal dystrophy^[38] and retinal dysplasia. Dogs which are intended to be bred should be examined by a veterinary ophthalmologist for an eye score.
• Hereditary myopathy, a rare inherited disorder that causes a deficiency in type II muscle fibre. Symptoms include a short stilted gait or “bunny hopping,” and in rare cases ventroflexion of the neck accompanied by a kyphotic posture.^[42]
• There is a small incidence of other conditions, such as autoimmune diseases and deafness in labs, either congenitally or later in life.^[16]
• Labradors often suffer from exercise induced collapse, a syndrome that causes hyperthermia, weakness, collapse, and disorientation after short bouts of exercise.^[43]

[edit] Other disorders

Labs are sometimes prone to ear infection, because their floppy ears trap warm moist air. Labs who spend a lot of time in water are additionally prone to infection. This is easy to control, but needs regular checking to ensure that a problem is not building up unseen. A healthy Labrador ear should look clean and light pink (almost white) inside. Darker pink (or inflamed red), or brownish deposits, are a symptom of ear infection. The usual treatment is regular cleaning daily or twice daily (being careful not to force dirt into the sensitive inner ear) and sometimes medication (ear drops) for major cases. As a preventative measure, some owners clip the hair carefully around the ear and under the flap, to encourage better air flow. Labradors also get cases of allergic reactions to food or other environmental factors.

[edit] Obesity

Labradors can easily become overweight, due to their enjoyment of treats, hearty appetites, and endearing behaviour towards people. Lack of activity is also a contributing factor. A healthy Labrador should keep a very slight hourglass waist and be fit and light, rather than fat or heavy-set. Excessive weight is strongly implicated as a risk factor in the later development of hip dysplasia or other joint problems and diabetes, and also can contribute to general reduced health when older. Osteoarthritis is common in older, especially overweight, Labradors. A 14 year study covering 48 dogs by food manufacturer Purina showed that labs fed to maintain a lean body shape outlived those fed freely, by around two years, emphasizing the importance of not over-feeding.^[44]

[edit] Appearance around the world

In the United States, the breed gained wider recognition following a 1928 American Kennel Gazette article, “Meet the Labrador Retriever”. Before this time, the AKC had only registered 23 Labradors in the country,^[7] in part because US and UK hunting styles had different requirements.^[45] Labradors acquired popularity as hunting dogs during the 1920s and especially after World War II, as they gained recognition as combining some of the best traits of the two favourite United States breeds as both game finders and water dogs.^[45]

Outside North America and Western Europe, the Labrador arrived later. For example, the Russian Retriever Club traces the arrival of Labradors to the late 1960s, as household pets of diplomats and others in the foreign ministry.^[46] The establishment of the breed in the Commonwealth of Independent States (ex-USSR) was initially hindered by the relatively small numbers of Labradors and great distances involved, leading to difficulty establishing breedings and bloodlines;^[46] at the start of the 1980s, home-born dogs were still regularly supplemented by further imports from overseas.^[46] Difficulties such as these initially led to Labradors being tacitly cross-bred to other types of retriever.^[46] In the 1990s, improved access to overseas shows and bloodlines is said to have helped this situation become regularised.^[46]

[edit] Demography

The Labrador is an exceptionally popular dog. For example as of 2006:

• Widely considered the most popular breed in the world.^[47][48]
• Most popular dog by ownership in USA (since 1991),^[49][50] UK,^[51] Australia,^[52] New Zealand^[53] Canada,^[54] and Israel.^[55]
• In both the UK and USA, there are well over twice as many Labradors registered as the next most popular breed.^[49][51] If the comparison is limited to dog breeds of a similar size, then there are around 3 – 5 times as many Labradors registered in both countries as the next most popular breeds, the German Shepherd and Golden Retriever.^[49][51]
• Most popular breed of assistance dog in the United States, Australia and many other countries, as well as being widely used by police and other official bodies for their detection and working abilities.^[4] Approximately 60–70% of all guide dogs in the United States are Labradors (see below).^[35]
• Seven out of 13 of the Australian National Kennel Council “Outstanding Gundogs” Hall of Fame appointees are Labradors (list covers 2000–2005).^[56]

There is no global registry of Labradors, nor detailed information on numbers of Labradors living in each country. The countries with the five largest numbers of Labrador registrations as of 2005 are: 1: United Kingdom 2: United States and France (approximately equal), 4: Sweden, 5: Finland.^[57][58] Sweden and Finland have far lower populations than the other three countries, suggesting that as of 2005 these two countries have the highest proportion of labs per million people:

Country	Population (millions)	Labrador registrations	Registrations per million pop.
Finland	5.2	2,236	426.0
France	60.5	9,281	153.4
Sweden	9.0	5,158	570.5
United Kingdom	59.7	18,554	311.0
USA	298.2	10,833	36.3

OFA statistics suggest that yellow and black labs are registered in very similar numbers (yellow slightly more than black); chocolate in lesser numbers.^[57][58]

Note: number of registrations is not necessarily the same as number of living dogs at any given time.

[edit] Famous labradors

As both the most popular breed by registered ownership and also the most popular breed for assistance dogs in several countries, there have been many notable and famous labradors since the breed was recognised.

A selection of a few of the most famous labradors within various categories includes:

Endal wearing his PDSA Gold Medal.

Assistance dogs

• Endal, a service dog in Britain. Among other distinctions, “the most decorated dog in the world” (including “Dog of the Millennium”^[59] and the PDSA’s Gold Medal for Animal Gallantry and Devotion to Duty),^[60] the first dog to ride on the London Eye and the first dog known to work a ‘chip and pin‘ ATM card. By Endal’s death in March 2009, he and his owner/handler Allen Parton had been filmed almost 350 times by crews from several countries, and a film of a year in Endal’s life was in production.^[61][62]

Police, military, rescue and detection dogs

• Zanjeer, a detection dog who detected arms and ammunition used in 1993 Mumbai (Bombay) serial explosions. During his service, his haul was excellent. He helped recover 57 country-made bombs, 175 petrol bombs, 11 military bombs, 242 grenades and 600 detonators. His biggest contribution to the police force and the city was the detection of 3,329 kg of RDX. He also helped detect 18 AK-56 rifles and five 9mm pistols.

• Lucky and Flo, twin Black Labrador counterfeit detection dogs who became famous in 2007 for “sniffing out nearly 2 million pirated counterfeit DVDs” on a six-month secondment to Malaysia in 2007.^[63] Following the multi-million dollar, 6-arrest Malaysian detection, they became the first dogs to be awarded Malaysia’s, “outstanding service award”,^[64] and software pirates were stated to have put a £30,000 contract out for their lives.^[65][66]

• Sabi, an Australian special forces explosives detection dog that spent almost 14 months missing in action (MIA) in Afghanistan before being recovered safe and well in 2009.^[67][68]

Pets

• Former President of the United States Bill Clinton‘s Labradors Buddy and Seamus.
• Former Russian President, and current Russian Prime Minister Vladimir Putin’s Labrador ‘Koni‘.

Fiction and media

• Labradors have featured variously as pets and significant characters in sitcoms and other TV shows, as well as other portrayals in the media. Bouncer in Neighbours, and Luath in The Incredible Journey, are two TV examples.
• Marley is an American Labrador featured in Marley & Me, a best-selling book by John Grogan, and a subsequent film based on Grogan’s life and times with Marley.

Mascots and advertising

• Since 1972, a yellow Labrador pup known as the Andrex Puppy has been an advertising symbol for Andrex (Cottonelle) toilet tissue.
• Michigan State University has an ongoing tradition of Zeke the Wonder Dog. The original “Zeke” was a yellow Lab, as is the current “Zeke III”, and “Zeke II” was a black Lab.

[edit] Significant crossbreeds

The “Labradoodle” is a popular “designer dog” that is a cross-bred Labrador and Poodle. Originating in Australia, the intent of breeding this cross was to try and create a service dog suitable for allergy sufferers. However the current fashionability of labradoodles has resulted in indiscriminate breeding, and there is no guarantee such a cross will inherit the hypo-allergenic poodle coat.

Some assistant-dog groups use Golden Retriever / Labrador Retriever hybrids (unofficially called a Golden Labrador Retriever) because they believe this cross produces dogs with a excellent temperaments.^[69] However, such crossbreeds are not immune to many of the problems suffered by purebreds, as Golden Retrievers and Labradors have similar health problems.

The assistance dog organization Mira utilises Labrador-Bernese Mountain Dog crosses (“Labernese”) with success.^[70]

[edit] See also

• Labrador Retriever coat colour genetics

[edit] References

[edit] Further reading

Wikimedia Commons has media related to: Labrador Retriever

• Cunliffe, Juliette (2004). The Encyclopedia of Dog Breeds. Parragon Publishing. ISBN 0-7525-8276-3.
• Fergus, Charles (2002). Gun Dog Breeds, a Guide to Spaniels, Retrievers, and Pointing Dogs. Guilford, CT: Lyons Press. ISBN 1-58574-618-5.