Guinea pigs (Cavia porcellus), also known as cavies, have been domesticated since . Selective breeding has produced a wide range of domestic guinea pig breeds, distinguished mainly by coat length, texture, colour, pattern, and body type.
Modern guinea pig breeds are used primarily as companion animals and exhibition animals. Some strains have also been developed for use as laboratory animals and model organisms in biomedical research.
As with most domesticated animals, guinea pig breeds exhibit a wide range of physical characteristics and serve various purposes. Some are show breeds, notable for their long, flowing hair, while others are laboratory breeds, used as model organisms in scientific research.
History and organizations
As early as the 500s CE, Indigenous peoples in South America selectively bred guinea pigs, known in the Andes as cuy. Early Andean varieties were kept mainly as livestock for food. These local landrace populations became part of the foundation for some modern domestic breeds.
Guinea pigs were exported to Europe in the late 16th or early 17th century, and later to North America in the 19th century, as part of the exotic pet trade. Their appeal as pets and exhibition animals was aided by the variety of their coat colours, patterns, and inherited traits.
As guinea pigs became established as companion and exhibition animals, breeders formed clubs and standards bodies to define and judge recognized breeds. The American Cavy Breeders Association governs guinea pig breeding in the United States and Canada and is affiliated with the American Rabbit Breeders Association.
In the United Kingdom, the British Cavy Council oversees cavy clubs and breed standards. The Rare Varieties Cavy Club works with the British Cavy Council to support new and emerging breeds.
In Australia and New Zealand, cavy breeding is governed by the Australian National Cavy Council and the New Zealand Cavy Council, respectively.
Breed standards
Each cavy organization publishes its own standard of perfection and determines which breeds are eligible for exhibition. New breeds and varieties continue to appear, although they may not be recognized by every standards body. The ARBA Cavy Standard of Perfection states that "a proposed new cavy breed must possess qualifications of individual merit, unique to itself, identifying it as a separate and distinct breed". The standard also requires breeders to maintain a quality herd that can breed true for three generations.
Guinea pigs are commonly described as either pet-quality or show-quality. A show-quality guinea pig is one that conforms closely enough to its breed standard to compete in exhibitions. A pet-quality guinea pig may be a mixed-breed animal, may have faults under a breed standard, or may otherwise be unsuitable for exhibition.
The American, Abyssinian, Peruvian, and Sheltie or Silkie are among the long-established breeds commonly seen in competitive cavy shows.
Most standards include broad requirements that apply across breeds. These commonly address head shape, eye and ear size, body condition, coat quality, and the clarity and distribution of coat colour.
Colorations
Cavies of various breeds have several colorations and patterns. For short-coated cavies, most colors constitute breed variations bred and shown separately from other colors. All colorations should be true throughout the coat, with the roots and tips being of same shade.
In the case of broken-colored cavies, i.e. any cavies with other than separately recognized combinations of colors, the coloring is described in order of magnitude (i.e., a mostly lilac cavy with some cream and a speck of white would be called "lilac-cream-and-white", while a mostly white cavy with a patch of red-black ticking would be "white-and-golden-agouti").
Self A self cavy is uniformly of one color, without any ticking or patterning. Self guinea pigs come in a variety of colors. The colors include black, chocolate, red, golden, buff, cream, white, lilac, beige, and slate.
Ticked
Ticked cavies have black series hairs with red series ticking, i.e. each individual hair has stripes of both a black and a red series color. In case a ticked cavy also has the tortoiseshell pattern, the red series patches are uniformly colored while the black series patch.
Agouti An agouti cavy has a solid colored belly and is otherwise fully ticked. Two common variations are the golden agouti, with black and red, and the silver agouti, with black and white. Any other color combinations in the US are called dilute agouti.
A solid agouti is completely ticked. Its variations are referred to like normal agoutis, i.e. a solid agouti with black and red would be called a golden solid agouti, and so forth.
Brindle A brindle cavy has intermixed hairs of both black and red series colors throughout their coats, with no ticking. An ideal show brindle appears uniformly colored, with both series appearing evenly all over.
Magpie A magpie cavy is a particular form of brindle, with black for the black series, but substituting white for the red series. Magpie can easily be confused with "roan", although in magpie the white hairs can appear anywhere on the cavy.
Dutch pattern
A Dutch cavy has a specific white pattern: a blaze on the face, a wide white band around the neck, chest, and the belly, including the front paws, and white tips on the hind feet. The pattern is essentially the same as the Dutch pattern in rabbits, and was named after it.
Himalayan pattern
A Himalayan cavy has a white body with colored points (face, ears, feet). It is an acromelanic, i.e. temperature-responding coloration, and its degree of darkness depends on how cool or warm the cavy is kept. Show Himalayans should have black or dark brown points with ruby, i.e. dark red, eyes. The darkest areas should be the face, paws, and the feet.
A Himalayan cavy is born solid white, the points slowly gaining color after a few weeks.
Tan pattern
A tan cavy is an otherwise solid black, with red ticking around the muzzle, around the eyes, in spots above the eyes, under the neck and the belly, and sparsely on the lower sides.
Otter and fox
Otter and fox cavies have yellow and white ticking, respectively. Different shades are named after the black series shade, for instance black otter, lilac-and-tan, and grey fox.
Tortoiseshell pattern A tortoiseshell ("tortie" for short) cavy has patches of red and black. An ideal show tortoiseshell cavy has regular, well-defined patches of each color on each side, and appears to have lengthwise "seams" on its back and belly, almost similar to brindle. Diluted tortoiseshells are called broken colors, and diluted tortoiseshell-and-whites tricolors. They follow the same pattern ideal.
Roan and Dalmatian A roan cavy has white hairs evenly intermixed on their body, while a Dalmatian (pattern) cavy has a white body with colored spots which can come in black, chocolate, or lilac. The latter is named after the spotted Dalmatian dog, and is not actually from Dalmatia. The head and the rump are mostly colored in both varieties. They are caused by the same gene, and whether a cavy appears roan or Dalmatian is defined by modifier factors. Many cavies have an intermediate roan/Dalmatian pattern, and these varieties are challenging to successfully breed in show quality.
The roan/Dalmatian factor, sometimes called the "lethal white gene" or simply "lethal gene", is incompletely dominant. While the roan/Dalmatian factor is consistently visible in heterozygous carriers that do not have other factors producing white hair, the pattern can be masked by extreme dilution (resulting in full white coloration) or extreme white spotting. The gene is lethal when homozygous, resulting in full white pups with varying combinations of deafness, blindness, loss of smell, and deformities. Some lethal pups may survive for some time, while others die soon after birth if not euthanized. Most roan/Dalmatian breeders breed them solely to lethal-non-carriers to avoid the 25% risk of homozygous pups that occurs breeding carrier-to-carrier.
Satin variants and satin syndrome
In addition to their standard form, nearly all breeds come in a satin variant. Satin variant guinea pigs have an unusually glossy coat that looks luminous, 'glassy', or 'oily'.
Satin guinea pigs are not a distinct breed; they have a recessive genetic trait that makes their hair shafts thinner and more translucent. This genetic trait is not connected to hair texture and can be found in guinea pigs with all coat types.
The American Cavy Breeders Association recognizes satin variants of the Abyssinian, American, Peruvian, Silkie, and Teddy breeds, and has unique standards for these variants.
The genes responsible for the satin coat can cause severe health concerns, including Paget's disease.Jordan, Julia. "Untersuchungen zur Osteodystrophia fibrosa beim Hausmeerschweinchen" (Cavia aperea f. porcellus) der Züchtung ‚satin' " 'Investigation of Osteodystrophia Fibrosa in Guinea Pigs (Cavia aperea f. porcellus) the "Satin" phenotype'. Dissertation, Freie Universität Berlin, 2006. It's most commonly linked to 'satin syndrome', also known as osteodystrophy. Osteodystrophy is an incurable and potentially painful metabolic disease of the bones; its symptoms appear in cavies at around 12 to 18 months of age. These symptoms include a wobbly gait, problems eating, and parturition complications in sows. Osteodystrophy is a progressive disease that can also cause weakness, paralysis, and, eventually, death.
Due to animal welfare concerns, many registries— including the New Zealand, Swedish, and Finnish guinea pig associations— refuse to register satin cavies or cavies with a satin parent.
American
The most widespread breed of guinea pig, the American guinea pig, is a recognized breed by the American Rabbit Breeders Association (ARBA).
They are entered and shown in ARBA competitions in nineteen color classifications; Black, Cream, Red, White, Any Other Self (Beige, Chocolate, Lilac, Red-Eyed Orange), Brindle, Roan, Dilute Solid, Golden Solid, Silver Solid, Dilute Agouti, Golden Agouti, Silver Agouti, Dalmatian, Dutch, Himalayan, Tortoise Shell & White, Any Other Marked (Broken Color and Tortoise Shell), and Tan Pattern (Black Tan, Blue Tan, Chocolate Tan, Beige Tan, and Lilac Tan).
The American should have a broad shoulder, Roman nose, and full crown, and the coat is to be short, straight and feel silky. The coat is faulted for feathering, harshness, or being too thin or long. Contestants are disqualified for ridges, rosettes, side whiskers, or a satin sheen, though this should not be confused with the natural luster of some varieties. The ears are to be drooping but not fallen, and the eyes are to be bold and bright. The American guinea pig is to be posed with the hind feet under the animal and the front feet slightly ahead of the shoulders, and should not be forced into a cobby position or stretched out.
The American is known for its sweet and docile temperament, and is often considered for first time cavy owners.
American Crested The American Crested is a short-haired guinea pig with a distinctive crest of hair on the top of its head that is a different color than the rest of its body.
English Crested An English Crested is a breed of guinea with a short, smooth coat and a crest on its head that is the same color as its body.
White Crested The White Crested is similar to the American, but they have one white rosette on the forehead. The breed standards and ideals are nearly identical, with the exception that a White Crested cavy's crest should be completely of a color different from the rest of the animal. Most usually the crest is white, as necessitated by the ACBA standard. No other white hair should be present in the animal. By this standard, White Cresteds are not bred in colorations that have white anywhere on the body, such as Dutch, roan, and Dalmatian.
Abyssinian