CAVIES AND MARAS: Caviidae

PHYSICAL CHARACTERISTICS

Cavies and maras, also called cavids (members of the family Caviidae), range in size from 8 to 30 inches (20 to 75 centimeters) and have a vestigial, no longer functional, tail. They generally have plump, robust bodies with large heads, and short limbs and ears. Their fur in the wild is short and coarse. Cavids have high-crowned jaw teeth that grow continuously. The size and shape of cavids range from small, tailless, short-legged cavies with body lengths of 5.9 to 15.7 inches (15 to 40 centimeters) and weights of 7.0 to 21.1 ounces (200 to 600 grams) to the larger, rabbit-like salt-desert cavies and maras with shorter tails and, slender limbs, that are 17.7 to 29.5 inches (45 to 75 centimeters) in length and weighs 2.2 to 35.2 pounds (1 to 16 kilograms). Cavies have four clawed front toes and three clawed rear toes. The rock cavy has padded feet and claw-like toes that help it climb rocks and trees. Cavies have flat-crowned teeth that are always growing.

GEOGRAPHIC RANGE

Cavies are found over most of South America, except Chile and some areas of the Amazon River basin. Maras inhabit southern Bolivia, Peru, and Argentina.

HABITAT

Cavies and maras are found in a variety of habitat, depending on the species. These include marshes, tropical floodplains, rocky mountain meadows, grassland, desert, and areas with lots of trees and bushes near water, grasslands, and cultivated lands. They are generally not found in dense jungle or rainforests.

DIET

Cavies and maras are herbivores, meaning they eat only plants, including grasses and cacti (KACK-tie, or KACK-tee), and plant material, such as seeds, flowers, and fruits.

BEHAVIOR AND REPRODUCTION

Cavies and maras are diurnal, meaning they sleep at night and are active during the day, or crepuscular (kri-PUS-kyuh-lur), meaning they are active at twilight. They do not hibernate and live in burrows they dig or were dug by other animals. They are generally very social, living in pairs or groups. Cavies and maras have a variety of mating regimens, including hierarchical promiscuity (HI-uh-raar-kick-al prah-miss-KYOO-it-ee), which is frequent sexual intercourse based upon ranking or status in the group; polygamy (puh-LIH-guh-mee), where they have multiple mates in a single breeding season; and monogamy (muh-NAH-guh-mee), which is having sexual relations with a single partner during the breeding season. They breed year round and produce multiple litters per year. Cavids have a gestation period, pregnancy, of fifty to seventy days. The number of offspring per litter is usually one to three but can be up to seven. Maras and salt-desert cavies have seasonal breeding patterns and have litters of one or two young.

NAME GAME

Guinea pigs are neither pigs nor from the African country of Guinea. So how did they get their common name? One theory is that when they were first introduced into Great Britain in the 1500s, they were the closest animal to a pig that could be bought for a guinea, an old British coin. Another is that the sounds they make reminded people of pigs, and since they were shipped to Europe via Guinea, people thought they originated from there.

CAVIES, MARAS AND PEOPLE

Cavies, commonly known as guinea pigs, have been domesticated, tamed, and used as pets for three thousand years. Scientists also use them extensively as laboratory animals. They are raised for food in areas of Ecuador, Peru, and Bolivia. Guinea pigs are believed to have been used by the ancient Incas in religious sacrifices. Small cavies are considered to be pests by farmers in agricultural areas. Larger cavies are hunted for food and their pelts, or fur.

FAMILY TREE FEUD

Taxonomists, scientists who classify living things, have always placed cavies and maras in the order of rodents (Rodentia) because they most resemble rats and mice. However, newer research into the genes of cavies and maras indicate they are not related at all to rodents. Instead, some scientists suggest that their genes, the basic units capable of transmitting characteristics from one generation to the next, more closely resemble those of primates.

CONSERVATION STATUS

No cavy species are currently listed as endangered by the World Conservation Union (IUCN). Maras, sometimes called Patagonian hares, are listed as Near Threatened, not currently threatened, but could become so, by the IUCN.

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ROCK CAVY (Kerodon rupestris): SPECIES ACCOUNTS

Physical characteristics: Rock cavies are about the same size or slightly larger than the common guinea pig, 11.8 to 15.7 inches (30 to 40 centimeters) long and weigh 31.7 to 35.2 ounces (900 to 1,000 grams). They have long, slender legs with well-developed, blunt nails on their padded feet and one claw used for grooming. The upper body fur is generally gray with irregular black and white patches. The lower body fur is yellow and brown while the throat fur is white. The face has a muzzle shape with a longer, blunter snout, similar to that of a dog.

Geographic range: Rock cavies are found in eastern Brazil from the state of Piaui to northern Minas Gerais.

Habitat: The species prefers dry areas with rocky outcroppings near mountains and hills.

Diet: Rock cavies are herbivores, meaning they eat only plants and plant material. Their diet primarily consists of tender leaves and shoots of plants.

Behavior and reproduction: Rock cavies received their name because they are excellent rock climbers. They are generally most active late in the day. Males claim one or several rock piles as their territory, which they will defend. Each male has a number of female mates and each group has a hierarchy, a structured order of rank. The gestation period is about seventy-five days. Rock cavies reach sexual maturity, the age when they can produce offspring, at two months. Females produce several litters per year from July to March, each with one or two young. Individuals make several vocal sounds, including a slow whistle when they leave their rock piles to search for food, and an alarm whistle. The average lifespan is six to eight years.

Rock cavies and people: Rock cavies are easily tamed and make suitable pets. Brazilians who live in the rock cavy habitat area use the mammal as food and medicine.

Conservation status: Rock cavies are not listed as threatened by the IUCN. ∎

MARA (Dolichotis patagonum): SPECIES ACCOUNTS

Physical characteristics: Maras, also called Patagonian maras or Patagonian hares, have a head and body length of 27.6 to 30 inches (69 to 75 centimeters) and a tail length of 1.6 to 2 inches (4 to 5 centimeters). They weigh form 17.6 to 35.2 pounds (8 to 16 kilograms). Their body shape looks like that of a long-legged rodent. The hind legs are slightly larger than the front legs, making them fast runners. The front feet have four toes and the back feet three toes with sharp claws. The fur of maras is grayish brown on the upper body and cream or white on the lower body. The rump has a large white patch of fur.

Geographic range: Maras are found in central and southern Argentina.

Habitat: Maras prefer milder foothill regions where there is coarse grass and scattered shrubs. They also are found in forested canyons and open grasslands.

Diet: Maras are herbivores. Their diet includes a variety of vegetation, such as leaves, grass, herbs, fruits, cactus, and seeds. In captivity, they eat primarily hay, leaves, vegetables, and oats.

Behavior and reproduction: Maras are diurnal and they live in groups of up to forty. They use a variety of movements, including walking, hopping like a rabbit, galloping like a horse, and stotting, which is bouncing on all four legs at once. They are very fast runners, capable of reaching 27.9 miles per hour (45 kilometers per hour). They make several vocal sounds, including a "wheet" when they want contact with another mara, and a grunt they use to threaten others. Maras are monogamous, meaning they have a sexual relationship with only one mate, for several years. Females give birth to three or four litters a year, each consisting of one to three offspring. Females reach sexual maturity at eight months. Gestation is 93 to 100 days. The average lifespan of the Pantagonian mara is five to seven years in the wild and up to ten years in captivity.

Maras and people: Maras are hunted in the wild for food and their skin. They are also tamed and used as pets.

Conservation status: Maras are listed as Near Threatened by the IUCN. Their numbers appear to be declining in the wild, due primarily to destruction of their habitat by humans. ∎

FOR MORE INFORMATION

Books:

Harris, Graham. A Guide to the Birds and Mammals of Coastal Patagonia. Princeton, NJ: Princeton University Press, 1998.

Macdonald, David. The New Encyclopedia of Mammals. Oxford, U.K.: Oxford University Press, 2001.

Nowak, Ronald M. Walker's Mammals of the World, 6th ed. Baltimore: Johns Hopkins University Press, 1999.

Siino, Betsy Sikora. The Essential Guinea Pig. Hoboken, NJ: Howell Book House, 1998.

Waters, Jo. The Wild Side of Pet Guinea Pigs. Chicago: Heinemann Library, 2004.

Periodicals:

Kolar, Patricia. "The C. porcellus: (a.k.a.) Pocket Pet." Hopscotch (August–September 2002): 46–48.

Kostel, Ken. "Guinea-zilla." Science World (December 8, 2003): 6–7.

Morales, Edmundo. "The Guinea Pig in the Andean Economy: From Household Animal to Market Commodity." Latin American Research Review (Summer 1994): 129–143.

Rowe, D. L., and R. L. Honeycutt. "Phylogenetic Relationships, Ecological Correlates, and Molecular Evolution Within the Cavioidea (Mammalia, Rodentia)."Molecular Biology and Evolution 19 (2002): 263–277.

Web sites:

"Dolichotis patagonum." Animal Diversity Web. http://animaldiversity.ummz.umich.edu/site/accounts/information/Dolichotis_patagonum.html (accessed on May 4, 2004)

"Family Caviidae." Animal Diversity Web. http://animaldiversity.ummz.umich.edu/site/accounts/information/Caviidae.html (accessed on May 4, 2004)