mara Familia caviidae

CAVIIDAE

Mara o liebre patagonica

PHYLUM: Chordata	CLASE: Mammalia	SUBCLASE: Eutheria	ORDEN: RODENTIA	SUBORDEN:	FAMILIA: CAVIIDAE
Genero: Dolichotis	Caviidae	Dolichotis patagonum	Referencias
Especie: patagonum	Biología de los cávidos
	The Caviidae is a family of rodents that occurs over most of South America. It includes two subfamilies: the Caviinae, the cavies and the familiar guinea pigs; and the Dolichotinae, the Patagonian hares, or maras. There are a total of five genera and fourteen species of caviids. Caviidae is a diverse family morphologically, including small forms such as Galea, which weighs up to 600 grams, and large forms such as Dolichotis, which weighs up to 16 kilograms. The members of the two subfamilies are quite distinct. The caviines have short limbs and ears and robust bodies, whereas the Patagonian hares are characterized by a rabbit-like body form with long ears and thin, long limbs. The nails of the caviines are short and either sharp or blunt; those of Dolichotis are hooflike on the hindfeet and clawlike on the forefeet. Cavies belonging to the great South American radiation of hystricognath rodents. This group arrived in South America probably in the early Oligocene, well before most other rodents, and diversified extensively. Nevertheless, the lower jaws of caviids are scarcely hystricognathous, appearing to have almost reverted to a sciurognathous condition. The mandibles have a well-developed masseteric crest running high along the sides, separated from the toothrow by a deep groove. The arrangement of their masseters and the areas of the cranium from which they originate (zygomatic arch, infraorbital canal, rostrum, etc.) are strongly hystricomorphous. The skulls have well-developed bullae that are noticeably enlarged in some species, and a substantial paroccipital process. Obvious dental characteristics distinguish the members of Caviidae from the members of other families of South American rodents. The dental formula for the family is 1/1, 0/0, 1/1, 3/3 = 20. The teeth are flat-crowned, hypsodont, and ever-growing (rootless). All teeth except the third molar have a simple pattern of two prisms, formed by one labial and one lingual reentrant fold. The rows of cheekteeth converge strongly anteriorly. Karyotypes are also highly conserved amongst the members of this family, with 2n=64. The tail is vestigial in all members of caviids. Among the most abundant and widely distributed of all South American hystricomorph rodents, caviids are found in habitats ranging from marshy, tropical floodplain to dry, rocky, high-altitude meadows. Some genera live in open grasslands, others are found in semiarid grasslands, barren zones, or in the Peruvian and Argentinian dry steppes and high mountains. Generally caviids are not found in heavy jungle. They range form Venezuela south to southern Patagonia; they are absent from Chile and some parts of the Amazon basin. Caviids are usually diurnal or crepuscular and do not hibernate. They shelter in burrows left by other animals or excavated by the caviids themselves. They are generally social, occurring in pairs or in groups. Some have complex social hierarchies. Members of this family may breed year-round; they have a gestation period (50 to 70 days) that is short for the group of rodents to which caviids belong. Young are well developed at birth and reach sexual maturity early. Caviids eat primarily plant material, but there is considerable variation in diet specializations within the family. For example, Microcavia eats leaves and fruits that it may obtain by ascending trees, whereas Cavia does not climb and eats only grasses. Members of the family Caviidae first appear in the fossil record in the mid-Miocene, 20 million years ago. The group underwent a radiation 5 to 2 million years ago, in the Pliocene; eleven genera are represented from that time. Cavies and guinea pigs have benefited humans for thousands of years. The domestic guinea pig, Cavia porcellus, now find worldwide except in the wild, has been bred for meat for more than three thousand years in South America. During the period of the Inca Empire, from 1200 to 1532, selective breeding resulted in many strains of the guinea pig. Since the mid-1800s this animal has been used for laboratory research. Today it is raised for meat by the natives of Ecuador, Peru, and Bolivia and is used widely as a pet. Kerodon, another genus of caviid, is also used as a pet and for food. Microcavia has negatively affected humans, as it is known to ruin crops, and its burrow entrances are a danger to horses.
	Dolichotis patagonum
	Mara
	Patagonian hare or mara are a Neotropical specie. They live in the pampas and monte of central and southern Argentina. They mass range between 8 to 16 kg, head and body length= 690-750mm with a tail of 40-50mm. The general body form of a Patagonian cavy is that of a long-legged rodent with a body similar to a hoofed animal. Maras are grayish-brown above and white below. The hindquarters have a large white patch. The stiff, dense hair is very fine in texture. The front feet have 4 toes, the back 3 all having a sharp claw. The hind legs are slightly larger than the front. The eyes and nose are large, and the ears are slightly pointed. They eat almost any vegetation but prefer grasses and herbs. Maras have very unusual reproductive behavior, especially for mammals. Monogomous for life. a cavy pair breeds two or three times a year, usually around mid-winter and spring, when the female enters her very brief estrus. The litters of 1-3 young are born after a 3 month gestation period. The young are well developed at birth and are quickly placed in a communal den, usually made from a hole or tunnel abandoned by another animal. This den is home to the offspring of as many as 15 cavy pairs. The adult pairs intermittently travel to the den to nurse their young. Pairs do not tolerate other pairs when nursing, and the males drive off other parents. The female uses scent to locate her young and drives off offspring other than her own. The young are weaned after 2-3 months and quickly reach sexual maturity (2-3 months for females, 6 months for males). Maras travel in mated pairs and are active mostly during the day. The home range is about 40 ha. The male always follows the female, on guard for rival males and predators. Very little territorality is evident, but males appear to have a dominance hierarchy. Patagonian cavies have a variety of locomotions. They may walk normally, hop in a rabbit-like fashion, gallop, or bounce on all fours (for long distance, high speed travel). These cavies have been clocked at speeds of 45 km/hr for more than 1000 meters. Cavies also vocalize with grunts, grumbles, and screams and spend a great deal of the day basking in the sun. Although cavies spend more of their time in pairs seasonally they will travel in very large groups (>70) to freshly evaporate lakes where food is extremely plentiful. Habitat Cavies prefer arid grasslands and brushlands with a great deal of open space. Biomes: temperate grassland, chaparral,
	Referencias

	Lawlor, Timothy. 1979. Handbook to the orders and families of living mammals. Mad River Press, Eureka, California. Macdonald, David. 1984. The encyclopedia of mammals. Facts on File Publications, New York. Nowak, Ronald M. and John L. Paradiso. 1983. Walker's mammals of the world. The Johns Hopkins University Press, Baltimore and London, pp 803-810. Vaughan, T. A. 1986. Mammalogy. Third Edition. Saunders College Publishing, Fort Worth. vii+576 pp. Wilson, Don E. and DeeAnn M. Reeder (eds.). 1993. Mammal species of the world: A taxonomic and geographic reference, 2nd ed.. Smithsonian Institution Press, Washington and London. Woods, C. A. 1984. Hystricognath rodents. Pp. 389-446 in Anderson, Sydney and J. Know Jones, Jr. (eds.). Orders and familes of mammals of the world. John Wiley and Sons, New York.

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