Cavy

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Caviidae
Fossil range: Middle Miocene–Recent
Mara, genus Dolichotis
Mara, genus Dolichotis
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Family: Caviidae
Fischer de Waldheim, 1817
Subfamilies

 Caviinae
 Dolichotinae
 Hydrochoerinae

Caviidae is a diverse family of South American rodents characterized by a short or rudimentary tail, large head, and continuously growing, flat-crowned jaw teeth, with twenty teeth in total. Well-known members are the domestic guinea pig and the capybara (although the capybara is sometimes placed in its own family of Hydrochaeridae). The family includes both members with stout bodies, short limbs, and short ears, and members with more rabbit-like bodies with long ears and long limbs.

Cavy is the common name often applied to members of this family, but more typically this term applies only to certain of the members of Caviidae, and in particular members of the genus Cavia. The more technical name used for members of this family are cavids, or less commonly caviids. There are about six genera and 15 species in Caviidae. They are found across the continent, in open areas from moist savanna to thorn forests or scrub desert.


Description

Members of the rodent family Caviidae are morphologically diverse. Some are stockily built with short legs, while others are rabbit-like with slender and long-legs. Some have sharp, clawed digits while others have hoof-like nails. Some appear tailless, with but a vestigial or rudimentary tail, while others have a short tail. While the fur is typically short, some have long hair (Honeycut 2004)..

Among characteristics that unite the group are the presence of twenty total teeth according to the formula 1/1, 0/0/, 1/1, 3/3 and the fact that the teeth of cavids are high-crowned and ever-growing. The cheekteeth converge strongly anteriorly and, with the exception of the third molar, all teech have a pattern of two prisms, formed by one labial and one lingual reentrant fold. The tail is short or vestigial and the skulls have well-developed bullae and a substantial paroccipital process. The mandibles have a masseteric crest that is well-developed and runs high along the sides, separated by a deep groove from the toothrow (Gorog and Myers 2000).

Three subfamilies commonly are recognized. The subfamily Caviinae includes the small, tailess, short-legged, short-eared, robust-bodied cavies and guinea pig, comprising the genera Cavia, Microcavia, and Galea. The subfamily Dolichotinae includes the more rabbit-like, long-limbed, long-eared maras (or Patagonian hares), of genera Dolichotis. The subfamily Hydrochoerinae includes the rock cavies and the capybara, comprising the genera Hydrochoerus and Kerodon (Myers et al. 2008).

However, some taxonomies recognize only two subfamilies, that of Caviinae and Dolichotinae, and the capybara is placed into its own family, Hydrochaeridae. Furthermore, traditionally the genus Kerodon (rock cavies) has been considered a member of the subfamily Caviinae along with the guinea pigs and other cavies. Molecular results have suggested nonetheless that Kerodon is most closely related to the capybara, and that the two evolved from within the Caviidae (Rowe and Honeycutt 2002). This led Woods and Kilpatrick (2005) to unite the two into the subfamily Hydrochoerinae within the Caviidae. Using a molecular clock approach, Opazo (2005) suggested that Kerodon diverged from Hydrochoerus (the capybara) in the late Middle Miocene.


Three distinct groups are generally recognized. The Caviinae subfamily includes



Cavids also range considerably in size from just 200 grams (7 ounces) and a head and body length of just 150 millimeters (5.9 inches) in length to those weighing 16 kilograms (35.3 pounds) and 750 millimeters in length (29.5 inches).

dult capybaras are the largest extant rodents. They may grow more than four feet (130 centimeters) long and 50 centimeters tall (1.6 feet), and commonly weigh more than 50 kilograms (110 pounds) (NZP 2007; Magalhaes 1992). Females are slightly heavier than males (CZ 2007).

Members of the subfamily Caviinae, which include the guinea pigs and the


typically placed into two or three subfamilies:


With the exception of the maras, which have a more rabbit-like appearance, caviids have short, heavy bodies, and large heads. They have no visible tails. They range in size from the smaller cavies at 22cm in body length, and 300 grams in weight, up to the capybara, the largest of all rodents at 106 to 134 cm in length, and with a body weight of 35 to 66 kilograms. Even larger forms existed in the Pliocene, such as Phugatherium, which was about the size of a tapir[1].

They are herbivores, eating tough grasses or softer leaves, depending on species. The dental formula is similar to that of other rodents:

1.0.1.3
1.0.1.3

Females give birth to two or three furred and active young after a gestation period of 50 to 90 days in most species, or 150 days in the capybara. In most species, they are sexually mature within a few months of birth, although in capybaras, maturity is not reached until around 18 months[2].

Social organisation varies widely among the group. Many cavies are promiscuous, forming no long-lasting social groups, although, in some species, males maintain harems of two or more females. In contrast, maras are monogamous, and form temporary colonial creches to care for the young of multiple mothers. Capybaras live in groups of around ten individuals, and sometimes many more, each with a single dominant male, and a number of females, subordinate males, and juveniles[2].

Classification

Family Caviidae

  • Subfamily Caviinae: Guinea pigs (cavies)
    • Genus Cavia, this genus is especially called cavy.
    • Genus Galea
    • Genus Microcavia: Desert cavies
  • Subfamily Dolichotinae
    • Genus Dolichotis: Patagonian hares, or maras
  • Subfamily Hydrochoerinae
    • Genus Hydrochoerus: Capybara
    • Genus Kerodon: Rock cavy

References
ISBN links support NWE through referral fees

Gorog, T. and P. Myers. 2000. Caviidae. (On-line), Animal Diversity Web. Accessed February 11, 2009 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Caviidae.html.

Myers, P., R. Espinosa, C. S. Parr, T. Jones, G. S. Hammond, and T. A. Dewey. 2008. Family Caviidae (cavies) The Animal Diversity Web (online). Accessed February 11, 2009 at http://animaldiversity.org. http://animaldiversity.ummz.umich.edu/site/accounts/classification/Caviidae.html#Caviidae

  • Opazo, J. C. 2005. A molecular timescale for Caviomorph rodents (Mammalia, Hystricognathi). Molecular Phylogenetics and Evolution, 37:932-937.
  • Rowe, D. L. and R. L. Honeycutt. 2002. Phylogenetic relationships, ecological correlates, and molecular evolution within the Cavioidea (Mammalia, Rodentia). Molecular Biology and Evolution, 19:263-277.


  • Woods, C. A. and C. W. Kilpatrick. 2005. Infraorder Hystricognathi. Pp 1538-1600 in Mammal Species of the World A Taxonomic and Geographic Reference (D. E. Wilson and D. M. Reeder eds.). Baltimore, Johns Hopkins University Press.


  • Woods, C. A. and C. W. Kilpatrick. 2005. Pp 1538-1600 in Mammal Species of the World a Taxonomic and Geographic Reference 3rd ed. D. E. Wilson and D. M. Reeder eds. Smithsonian Institution Press, Washington D.C.

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  1. Savage, RJG, & Long, MR (1986). Mammal Evolution: an illustrated guide. New York: Facts on File, 125–126. ISBN 0-8160-1194-X. 
  2. 2.0 2.1 Herrera, E., Lacher, T.E., Macdonald, D., & Taber, A.B. (1984). in Macdonald, D.: The Encyclopedia of Mammals. New York: Facts on File, 690–699. ISBN 0-87196-871-1.