There are many breeds of guinea pig or cavy which have been developed since its domestication ca. 5000 BC. Breeds vary widely in appearance and purpose, ranging from show breeds with long, flowing hair to those in use as model organisms by science. From ca. 1200 AD to the Spanish conquest of the Inca Empire in 1532, selective breeding by indigenous South American people resulted in many landrace varieties of domestic guinea pigs, which form the basis for some of the modern, formal breeds. Early Andean varieties were primarily kept as agricultural stock for food, and efforts at improving the guinea pig as a food source continue to the modern era.
With the export of guinea pigs to Europe in the 15th century, the goal in breeding shifted to focus on the development of appealing pets. To this end, various competitive breeding organizations were founded by fanciers. The American Cavy Breeders Association, an adjunct to the American Rabbit Breeders Association, is the governing body in the United States and Canada. The British Cavy Council governs cavy clubs in the United Kingdom. Similar organizations exist in Australia (Australian National Cavy Council) and New Zealand (Combined Cavy Clubs New Zealand). Each club publishes its own Standard of Perfection and determines which breeds are eligible for showing. New breeds continue to emerge in the 21st century.
Though there are many breeds of guinea pig, only a few breeds are commonly found on the show table as pets. Most guinea pigs found as pets were either found undesirable by breeders or were bred to be pleasant pets regardless of how well they meet the breed standard of perfection. The English/American Short-haired, the Abyssinian (rough-coated), the Peruvian (long-coated), and the Sheltie (a.k.a. Silkie, long-coated) breeds are those most frequently seen as pets, and the former three are the core breeds in the history of the competitive showing of guinea pigs. In addition to their standard form, nearly all breeds come in a Satin variant. Satins, due to their hollow hair shafts, possess coats of a special gloss and shine. However, there is growing evidence that the genes responsible for the satin coat also can cause severe bone problems, including osteodystrophy and Paget's disease. Showing satin variations is prohibited by some cavy breeders' associations because of animal welfare reasons.
All cavy breeds have some shared general standards: the head profile should be rounded, with large eyes and large, smooth ears. The body should be strong and of compact build. Coat colour should in all variations be clearly defined and thorough from root to tip. These standards are best met by long established, commonly bred breeds, as their breeders have had enough time and animals to effectively breed for these qualities. The coat colour ideal of good definition and thoroughness is rarely met by other than the smooth-coated breeds, which have had well established, separate breeding lines for different colours.
The smooth-coated cavy breeds are named for their short, smooth coat. The coat should be full, smooth, of consistent short length, and have good "fall", i.e. return smoothly to normal in an instant when brushed back.
Both crestless and crested smooth-coated breeds are bred and shown in all colours and patterns, for instance self, Dalmatian, Himalayan, Tortoiseshell, Roan, Magpie, etc.
The short-coated cavy - often called the American or English - has consistently short hair without any rosettes. This breed of cavy most resembles the species's relatives and ancestors in the Cavia genus.
American Crested (a.k.a. White Crested or simply Crested)
The American Crested, referred to simply as the Crested by ACBA and as the White Crested by ANCC, closely resembles the English Crested, in having a single rosette on the forehead. The breed standards and ideals are nearly identical, with the exception that an American 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, American Cresteds are not bred in colourations that have white anywhere on the body, such as Dutch, roan, and Dalmatian. They are the most popular breed of guinea pigs.
The Ridgeback is a very common breed with a smooth short coat, with a lengthwise ridge of standing hair on its back. The ridge should ideally be short, regular, straight and should look like a mountain top . It should go from the head to neck . Ridgeback cavies as well as non-ridged carriers of the genetic ridgeback factor both have so called tufty feet, with the hair on the hind feet growing "the wrong way", upwards on the leg. Ridgeback cavies sometimes have rosettes on the body, which is considered a fault.
The Ridgeback is a recognized breed in the UK and is show under the guidance of the Rare Varieties cavy club and is also recognized as a Rare Variety in Sweden.
Satin coat variants
The satin is a variety with a characteristic satin-like, almost glassy sheen to its coat like its name suggests. The genetic factor for satin coat is recessive and found in all types of coat, long, rough, curly and short. Satin coat is linked to Osteodystrophy (OD), an incurable and potentially painful metabolic disease of the bones. OD symptoms begin showing at around 12 to 18 months, including wobbly gait, problems with eating, and with sows, parturition complications. Due to animal welfare concerns, some registries such as the Swedish and Finnish guinea pig associations, refuse to register satin cavies or cavies with a satin parent.
The long-coated cavy breeds show the characteristic of a notably long coat. Their breed standards opt for a long coat of consistent quality, and general conformation and colour quality are secondary to this, although not ignored. All long-coated breeds are shown in two divisions: unclipped and clipped. Unclipped cavies are generally pups or young adults, as keeping the coat in its maximum length and full quality is very challenging for the owner, and may be stressful for the animal. Once a long-coated cavy has had its hair cut down for any measure, and for any reason, it enters the clipped division permanently.
A Silkie has long, smooth coat that flows back over the body. A Silkie must never have any rosettes or any hair growing in a direction towards its face. Its coat should not have a part. When viewed from above, a Silkie and its coat forms a teardrop shape. The coat is generally accepted to have a somewhat longer sweep of hair in the rear.
A Texel has a long coat flowing back over the body like with a Silkie's, with the difference that the coat is curly. Originating from England, the Texel was officially recognized as a breed by the ACBA in 1998. According to the US standard, the curls should ideally be tightly wound corkscrew curls and should cover the entire body, including the stomach. A lengthwise part in the coat is acceptable. However, the original standard from England, where the breed originated, states, that the Texel is the rexoid equivalent of the Sheltie, and therefor, the Texel should be combed out the same way you would comb out a sheltie, though still show a rexoid appearance.
The Peruvian resembles the Silkie with its smooth coat, but has a prominent "forelock" resulting from a portion of its coat on the head and the neck growing forward on the body.
The Alpaca resembles a Peruvian with a "forelock", but it has curly coat. It is a relatively rare breed.
The Coronet resembles the Silkie with its smooth coat growing backwards over its body, but it has a crest on its forehead. Like with the short-coated crested breeds, this crest should be symmetrical with a tight centre and no sticking hairs.
Merino (English Merino)
The Merino resembles the Coronet, but has curly hair.
The Lunkarya, sometimes Lunk for short, is a new breed group developed first in Sweden, and mainly seen in the Nordic countries. It has a long, rough, curly coat that should be very dense and full. The group has three breed variations: the Lunkarya Peruvian (with a prominent forelock), the Lunkarya Sheltie (with the hair flowing back over the body), and the Lunkarya Coronet (with a crest on the forehead).
It was initially described as a dominant rex Peruvian, but later was named Lunkarya, a variation of the last name of breed's creator Lundqvist.
Sheba (Sheba Mini Yak)
The Sheba is a long haired, rosetted cavy, characterized by mutton chop whiskers, with frontal, presented to one side of the face, and in a naturally tousled appearance. They have been recognized as a cavy breed in Australia. Their breed standard was developed by Wynne Eecen of Sydney New South Wales, in the 1970s, and was published in her book Pigs Isn't Pigs. Often referred to as the "Bad Hair Day" Cavy.
The Abyssinian has a short, rough coat with anywhere from 6-8 tufts rosettes on its shoulders, sides, back, and backside. The derivation of the breed's name is unknown, but does not connote an origin in the geographical region of Abyssinia (present day Ethiopia).
The ideal Abyssinian's rosettes are all well-formed: fully formed with tight centres without hairs sticking out. They should be located symmetrically, one on each shoulder, four across the back, one on each of the hips, and two on the rump. The ridges between two rosettes should ideally stand rigidly straight, without breaking down onto either side even if pressed down lightly with the palm of a hand. All colours and patterns are accepted, although some colourations are much more common than others.
Some judging bodies, such as the ANCC, consider shoulder rosettes optional but desired in show Abyssinians.
A Rex has short, rough hair that stands on end all over the body. The hair should be of uniform length and texture all over, and no more than 1â2Â inch (1 1â4Â cm) in length, preferably shorter. The Rex resembles the Teddy but the similar coats of the two breeds are result from separate genetic factors.
A Teddy has a short, rough, very dense and springy coat that stands up all over the body. The hair typically grows to a moderate length and generally makes this breed resemble a soft toy more than any other. Another unique feature of the Teddies in the USA is the relatively long hair coating their bellies. The Teddy resembles the Rex but the similar coats of the two breeds are result from separate genetic factors.
Few varieties of hairless Guinea pig exist, the most prevalent breeds being the Skinny pig and the Baldwin. They are two separate breeds, with different genetic factors rendering them hairless. Hairless cavies in general need warmer accommodation and more energy-rich food to compensate for the loss of body heat. They are also susceptible to draught, drying of the skin, and skin infections without careful husbandry.
The Skinny is a mostly hairless breed, with some short rough hair on the face and the feet. Pups are born nearly hairless.
The breed was developed from a hairless laboratory strain crossed with Teddies and other haired breeds.
The Baldwin is a nearly hairless breed. Baldwins are born with a full coat, which sheds out with age until only a little hair remains on the feet.
The breed was developed from spontaneously mutated pups born to American Crested parents of a single breeder.
Cavies of various breeds have several colourations and patterns. For short-coated cavies, most colours constitute breed variations bred and shown separately from other colours. All colourations should be true throughout the coat, with the roots and tips being of same shade.
In case of broken-coloured cavies, i.e. any cavies with other than separately recognised combinations of colours, the colour 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.
A self cavy is uniformly of one colour, without any ticking or patterning. Self colours are divided into three groups: the black series (with black and its dilutions), the red series (with red and its dilutions), and the whites. When discussing ticked and patterned colourations, the self colour terms are used to denote specific shades.
A black cavy is black, with black eyes and black skin. The coat should be as dark as possible.
A chocolate cavy is deep brown, with black eyes and black skin. The colour often fades into a greyish brown or even steel grey, especially in long-coated cavies. However there are lines that do not usually fade.
A red cavy is reddish brown, with black eyes and black skin. The coat should be as deeply red as possible.
A white cavy is completely pure white, with either clear red (pink-eyed white, PEW) or black eyes (dark-eyed white, DEW).
Ticked cavies have black series hairs with red seried ticking, i.e. each individual hair has stripes of both a black and a red series colour. In case a ticked cavy also has the tortoiseshell pattern, the red series patches are uniformly coloured while the black series patch.
An agouti or argente cavy has a solid coloured belly and is otherwise fully ticked. Variations with black or chocolate (with dark eyes) are called agouti, and variations with beige, grey, and lilac (with red eyes) are called argente. Two common variations are the golden agouti, with black and red, and the silver agouti, with black and white.
- Solid agouti and solid argente
A solid agouti or argente cavy is completely ticked. Its variations are referred to like normal agoutis and argentes, i.e. a solid argente with beige and golden would be called a golden solid argente, and so forth.
A brindle cavy has intermixed hairs of both black and red series colours throughout their coats, with no ticking. An ideal show brindle appears uniformly coloured, with both series appearing evenly all over.
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.
A Himalayan cavy has a white body with coloured points (face, ears, feet). It is an acromelanic, i.e. temperature-responding colouration, and its degree of darkness depends on how cool or warm the cavy is kept in. 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 colour after a few weeks. These guinea pigs are thought to originate in southeast Asia, similar to the Himalayan, Siamese and related cat breeds.
A magpie cavy is a particular form of brindle, with black for the black series and white for the red series. It can easily be confused with Roan, although in magpie the white hairs can appear anywhere on the cavy.
- Tan, otter, fox
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 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.
A tortoiseshell ("tortie" for short) cavy has patches of red and black. An ideal show tortoiseshell cavy has regular, well-defined patches of each colour on each side, and appears to have lengthwise "seams" on its back and belly. Diluted tortoiseshells are called broken colours, and diluted tortoiseshell-and-whites tricolours. They follow the same pattern ideal.
- Roan and Dalmatian
A roan cavy has white hairs evenly intermixed on their body, while a Dalmatian cavy has a white body with coloured spots. The latter is named after the spotted Dalmatian dog, and is not actually from Dalmatia. The head and the rump are mostly coloured 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 an incomplete dominant. It is lethal when homozygous, resulting in full white pups with varying combinations of deafness, blindness, loss of smell, and deformities. Some homozygous pups may survive for some time, while others die soon after birth if not euthanised. Most roan/Dalmatian breeders breed roan/Dalmatian solely to non-carriers to avoid the 50% risk of homozygous pups for breeding carrier to carrier.
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 colouration) or extreme white spotting.
- Home page for the Australian National Cavy Council Inc
- Cavy genetics
- List of breeds from the American Cavy Breeders Association