''Cavia'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

in the subfamily

Caviinae Caviinae is a subfamily uniting all living members of the family Caviidae with the exception of the maras, capybaras, and '' Kerodon''. The subfamily traditionally contained the guinea pig or cavy-like forms along with the cursorially adapted ...

that contains the

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

s commonly known as the guinea pigs or cavies. The best-known

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

in this genus is the domestic guinea pig, ''

Cavia porcellus The guinea pig or domestic guinea pig (''Cavia porcellus''), also known as the cavy or domestic cavy ( ), is a species of rodent belonging to the genus ''Cavia'', family Caviidae. Animal fancy, Breeders tend to use the name "cavy" for the ani ...

'', a meat animal in

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

and a common household pet outside that continent.

Characteristics

General characteristics

The true guinea pigs are medium-sized rodents. They reach a head-body length of 20 to 35 centimeters (8 to 14 inches) and a weight of 500 to a maximum of 1,000 grams. The largest species of the genus is the

greater guinea pig ''Cavia magna'', commonly known as the greater guinea pig, is a species of rodent in the family Caviidae, native to South America. It is found primarily in the coastal regions of southern Brazil and Uruguay, inhabiting grasslands, marshes, and o ...

(''Cavia magna''). The species are very similar in habit and appearance, the long and relatively rough fur is usually grayish or brown to reddish-brown in color. The coloring can be variable, especially in species with a large distribution area and several subspecies. The head is relatively large in relation to the body, the eyes are large and the ears are small. The legs are short and strong, the front feet have four toes and the hind feet have three, all of which end in sharp claws, the middle one being the longest. ''Caviinae, Genus Cavia.'' In: Thomas E. Lacher, Jr.: ''Family Caviidae'' In: Don E. Wilson, T.E. Lacher, Jr., Russell A. Mittermeier (Herausgeber): ''Handbook of the Mammals of the World: Lagomorphs and Rodents 1.'' (HMW, Band 6) Lynx Edicions, Barcelona 2016, S. 433–434. ISBN 978-84-941892-3-4. Jonathan L. Dunnum: ''Genus Cavia Pallas, 1766'' In: James L. Patton, Ulyses F.J. Pardinas, Guillermo D’Elía (Hrsg.): ''Mammals of South America, Volume 2 – Rodents.'' The University of Chicago Press, Chicago 2015; S. 691–704, hier 691–692. ISBN 978-0-226-16957-6. All species of the genus are also tailless. ''Systematics.'' In: Thomas E. Lacher, Jr.: ''Family Caviidae'' In: Don E. Wilson, T.E. Lacher, Jr., Russell A. Mittermeier (Herausgeber): ''Handbook of the Mammals of the World: Lagomorphs and Rodents 1.'' (HMW, Band 6) Lynx Edicions, Barcelona 2016, S. 406–407. ISBN 978-84-941892-3-4.

Characteristics of the skull and teeth

Guinea pigs have a typical rodent dentition with

incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...

s (incisivi) and a gap between the teeth (

diastema A diastema (: diastemata, from Greek , 'space') is a space or gap between two teeth. Many species of mammals have diastemata as a normal feature, most commonly between the incisors and molars. More colloquially, the condition may be referred to ...

). In both the upper and lower jaws, there is one

premolar The premolars, also called premolar Tooth (human), teeth, or bicuspids, are transitional teeth located between the Canine tooth, canine and Molar (tooth), molar teeth. In humans, there are two premolars per dental terminology#Quadrant, quadrant in ...

and three

molars The molars or molar teeth are large, flat tooth, teeth at the back of the mouth. They are more developed in mammal, mammals. They are used primarily to comminution, grind food during mastication, chewing. The name ''molar'' derives from Latin, '' ...

in each half. Overall, they have a set of 20 teeth, like all guinea pigs. „Morphological Aspects“ In: Thomas E. Lacher, Jr.: ''Family Caviidae'' In: Don E. Wilson, T.E. Lacher, Jr., Russell A. Mittermeier (Herausgeber): ''Handbook of the Mammals of the World: Lagomorphs and Rodents 1.'' (HMW, Band 6) Lynx Edicions, Barcelona 2016, S. 406–407. The teeth are

hypsodont Hypsodont is a pattern of dentition characterized by with high crowns, providing extra material for wear and tear. Some examples of animals with hypsodont dentition are cows and horses; all animals that feed on gritty, fibrous material. The oppos ...

like all species of guinea pigs and converge towards the front. The crowns are prismatic and the teeth grow throughout life. In contrast to the yellow-toothed cavies (''Galea''), the teeth are white in colour. The jaws of all guinea pigs are

hystricomorphous The zygomasseteric system (or zygomasseteric structure) refers to the anatomical arrangement of the masseter muscle and the zygomatic arch (cheek bone) in the skulls of rodents. This system plays a crucial role in the diverse chewing mechanics ...

("porcupine-like"): the angular process growing from the rear end of the lower jaw is not in line with the rest of the jaw, as is the case with other rodents with a

sciuromorphous The zygomasseteric system (or zygomasseteric structure) refers to the anatomical arrangement of the masseter muscle and the zygomatic arch (cheek bone) in the skulls of rodents. This system plays a crucial role in the diverse chewing mechanics ...

("squirrel-like") jaw structure, but is angled sideways. The

masseter muscle In anatomy, the masseter is one of the muscles of mastication. Found only in mammals, it is particularly powerful in herbivores to facilitate chewing of plant matter. The most obvious muscle of mastication is the masseter muscle, since it is the ...

, a jaw muscle, runs partially through the

infraorbital foramen In human anatomy, the infraorbital foramen is one of two small holes in the skull's upper jawbone ( maxillary bone), located below the eye socket and to the left and right of the nose. Both holes are used for blood vessels and nerves. In anatomic ...

, which is correspondingly enlarged; moreover, like all representatives of the

Hystricognathi The Hystricognathi are an infraorder of rodents, distinguished from other rodents by the bone structure of their skulls. The masseter medialis (a jaw muscle) passes partially through a hole below each eye socket (called the infraorbital foramen) ...

, they lack the infraorbital plate. The species of true guinea pigs can be regarded as comparatively primitive in terms of skull structure. They have only a slight interorbital constriction of the skull, pan elongated paroccipital process of the

occipital bone The occipital bone () is a neurocranium, cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone lies over the occipital lob ...

, a relatively short

hard palate The hard palate is a thin horizontal bony plate made up of two bones of the facial skeleton, located in the roof of the mouth. The bones are the palatine process of the maxilla and the horizontal plate of palatine bone. The hard palate spans ...

and enlarged

tympanic cavity The tympanic cavity is a small cavity surrounding the bones of the middle ear. Within it sit the ossicles, three small bones that transmit vibrations used in the detection of sound. Structure On its lateral surface, it abuts the external audit ...

. The skulls of the mountain cavies correspond to those of the true guinea pigs, but are significantly more compact and rounded.

Former taxonomic controversy

''Cavia'' is classified in order Rodentia, although there was once a minority belief in the scientific community that evidence from

mitochondrial DNA Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondrion, mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the D ...

and proteins suggested the

might belong to a different

evolution Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, re ...

ary offshoot, and therefore a different order. If this had been so, it would have been an example of

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last comm ...

. However, this uncertainty is largely of historical interest, as abundant molecular genetic evidence now conclusively supports classification of ''Cavia'' as rodents. This evidence includes draft genome sequences of ''

'' and several other rodents.

Species

Historically, there has been little consensus in regard to the number of ''Cavia'' forms and their taxonomic affiliations. Morphological characters differentiating between ''Cavia'' species are limited and levels of inter- and intraspecific morphologic variation have not been well documented, thus, interpretations have varied and resulted in very different taxonomic conclusions. Three scientists disagreed on the number of species, Tate (1935) recognized 11 species, while Cabrera (1961) recognized seven, and Huckinghaus (1961) recognized only three. Recent scientific compilations have generally followed either Cabrera or Huckinghaus.Dunnum, Jonathan L, Salazar-Bravo, Jorge (21 January 2010), "Molecular systematics, taxonomy, and biogeography of the genus Cavia (Rodentia:Caviidae) Page 1 Guinea pig eating grass leaves

At least five wild species of guinea pig are recognised, in addition to the domestic form: *''

Cavia aperea The Brazilian guinea pig (''Cavia aperea'') (''preá'' in Portuguese) is a wild guinea pig species found in Argentina, Brazil, Bolivia, Colombia, Ecuador, Guyana, Paraguay, Uruguay and Venezuela. ''Cavia aperea'' has been successfully mated to ...

'' – Brazilian guinea pig, widespread east of the Andes *''

Cavia fulgida The shiny guinea pig (''Cavia fulgida'') is a guinea pig species of southeastern South America. The rodent is endemic to Brazil. It is native to the Atlantic Forest ecoregions. Taxonomy Wagler first called the species ''Cavia fulgida'' in 18 ...

'' – shiny guinea pig, eastern Brazil *''

Cavia intermedia Santa Catarina's guinea pig (''Cavia intermedia'') or Moleques do Sul cavy is a rare guinea pig species of southeastern South America. Distribution The small mammal is endemic to the , located in the state of Santa Catarina in southern Brazil ...

'' – intermediate guinea pig, Moleques do Sul islands, Santa Catarina, Brazil, first described in 1999 *''

Cavia magna ''Cavia magna'', commonly known as the greater guinea pig, is a species of rodent in the family Caviidae, native to South America. It is found primarily in the coastal regions of southern Brazil and Uruguay, inhabiting grasslands, marshes, and o ...

'' – greater guinea pig,

Uruguay Uruguay, officially the Oriental Republic of Uruguay, is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast, while bordering the Río de la Plata to the south and the A ...

, southeast Brazil *''

'' – domestic guinea pig, wild ancestor is likely: *''

Cavia tschudii The montane guinea pig (''Cavia tschudii'') is a species of caviid rodent found in the Andes in South America. The montane guinea pig is the likely main ancestor of ''Cavia porcellus'', the domestic guinea pig or domestic cavy, which appears to ...

'' – montane guinea pig,

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

south to northern Chile and northwest

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

Some authors also recognise the following additional species: *''

Cavia anolaimae ''Cavia anolaimae'' is a guinea pig species from South America. It is found in Colombia near Bogotá. It is believed to be a feral offshoot of the domestic guinea pig, ''Cavia porcellus'', and is often treated as a synonym of ''C. porcellus'', ...

'' (often considered a synonym of ''C. porcellus'' or a subspecies of ''C. aperea'') –

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

*''

Cavia guianae ''Cavia guianae'' is a guinea pig species from South America. It is found in southern Venezuela, Guyana, and portions of northern Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is th ...

'' (often considered a synonym of ''C. porcellus'' or a subspecies of ''C. aperea'') –

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

Guyana Guyana, officially the Co-operative Republic of Guyana, is a country on the northern coast of South America, part of the historic British West Indies. entry "Guyana" Georgetown, Guyana, Georgetown is the capital of Guyana and is also the co ...

, Brazil *''

Cavia patzelti ''Cavia patzelti'', commonly known as the Sacha guinea pig, is a species of ''Cavia'' native to Ecuador Ecuador, officially the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on th ...

'' (often considered a synonym of ''C. aparea'') -

Ecuador Ecuador, officially the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean on the west. It also includes the Galápagos Province which contain ...

In addition, four fossil species have been identified: *†''Cavia cabrerai'' - early

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

Brazil *†''Cavia vates'' – late Pleistocene Brazil

References

External links

{{Authority control * Cavies Rodents of South America Mammals of the Andes Pleistocene rodents Quaternary mammals of South America Middle Pleistocene Extant Pleistocene first appearances Rodent genera Taxa named by Peter Simon Pallas