Cavy Cousins

Cavy Cousins

Guinea Pigs, Capybara, Pacas, and Agoutis

Last updated: 15 Aug 96

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Guinea Pig/Cavy Family

There are about 15 species in this interesting and entirely South American family of ground-living rodents. Within the group are forms known as guinea pigs or cavies, mocos or rock cavies, and the Patagonian "hares," locally called "mares." Cavies and rock cavies have the well-known chunky body shape of domestic guinea pigs, with short ears and limbs, a large head and a tail which is not externally visible. Maras have a more harelike shape, with long legs and upstanding ears.
   Cavies feed on plant material, and their cheek teeth continue to grow throughout life to counteract the heavy wear caused by chewing such food. Most live in small social groups of up to 15 or so individuals; sometimes they join in larger groups of as many as 40. They do not hibernate, even in areas which experience low temperatures.

NAME: Cavy, Cavia tschudii
RANGE: Peru to N. Argentina
HABITAT: grassland, rocky regions
SIZE: body: 20-40 cm (7.75-15.75 in)
tail: no visible tail



These nocturnal rodents usually live in small family groups of up to 10 individuals, but may form larger colonies in particularly suitable areas. Although their sharp claws are well suited for digging burrows, they often use burrows made by other species or shelter in rock crevices. They feed at dawn and dusk, largely on grass and leaves.
   Cavies breed in summer, or throughout the year in mild areas, producing litters of 1 to 4 young after a gestation of 60 to 70 days. The young are well developed at birth and can survive alone at 5 days old. This species is the probable ancestor of the domestic guinea pig, which is kept as a pet and also widely used in scientific research laboratories. Cavies are still kept by upland Indians as a source of fine, delicate meat.

NAME: Rock Cavy, Kerodon rupestris
RANGE: N.E. Brazil
HABITAT: arid rocky areas
SIZE: body: 2040 cm (7.75-15.75 in)
tail: no visible tail

Rock Cavy


Similar in build to the cavy, the rock cavy has a longer, blunter snout and longer legs. It shelters under rocks or among stones and emerges in the afternoon or evening to search for leaves to eat. It will climb trees to find food.
   The female rock cavy is believed to produce two litters a year, each consisting of 1 or 2 young.

NAME: Mara, Dolichotis patagona
RANGE: Argentina
HABITAT: open arid land
SIZE: body: 6975 cm (27.25-29.5 in)
tail: 4.5 cm (l.75 in)



The mare has long, slender legs and feet well adapted for running and bounding along at speeds as great as 30 km/h (18.5 mph) in the manner of a hare or jackrabbit. Indeed, the mare fills the niche of the hare in an area where the latter is absent.
   On each hind foot there are three digits, each with a hooflike claw; each forefoot bears four digits, armed with sharp claws. Maras are active in the day' time and feed on any available plant material. They dig burrows or take them over from other animals, and the litter of 2 to 5 young is born in a nest made in the burrow.

Capybara Family

This family contains only 1 species, the capybara, which is the largest living rodent. It resembles a huge guinea pig with a large head and square muzzle, and lives in dense vegetation near lakes. rivers or marshes.

NAME: Capybara, Hydrochoerus
RANGE: Panama to E. Argentina
HABITAT: forest, near water
SIZE: body: 1-1.3 m (3.25-4.25 ft)
tail: vestigial



The capybara spends much time in water and is an excellent swimmer and diver; it has partial webs between the digits of both its hind feet and forefeet. When swimming, only its eyes, ears and nostrils show above the water. Capybaras feed on plant material, including aquatic plants, and their cheek teeth grow throughout life to counteract the wear and tear of chewing. They live in family groups and are active at dawn and dusk. In areas where they are frequently disturbed, capybaras may be nocturnal.
   Males and females look alike, but there is a scent gland on the nose that is larger in the male. They mate in spring, and a litter of 2 young is born after a gestation of 15 to 18 weeks. The young are well developed at birth.

Pacarana Family

This South American family contains 1 apparently rare species, the false paca, or pacarana, so called because its striking markings are similar to those of the paca.

NAME: Pacarana, Dinomys branicki
RANGE: Colombia to Bolivia
HABITAT: forest
SIZE: body: 73-79 cm (28.75-31 in)
tail: 20 cm (7.75 in)



The pacarana is a slow-moving, docile animal with short, strong limbs and powerful claws. It feeds on plant material, such as leaves, stems and fruit, and sits up on its haunches to examine and eat its food. Its cheek teeth are subject to considerable wear and grow throughout its life. It is most probably nocturnal.
   Little is known of its breeding habits, but 2 young seems to be the normal number in a litter.

Paca and Agouti Family

The 12 species in this family are distributed throughout Central and South America. All are medium to large ground-living rodents, with limbs well adapted for running.
   The group splits naturally into three: the nocturnal paces, the daytime-active agoutis, and the acuchis, about which little is known. All species have been hunted extensively for their flesh; they themselves eat leaves, fruit, roots and stems, all of which may be hoarded in underground stores.

NAME: Paca, Cuniculus pace
RANGE: S. Mexico to Suriname, south to Paraguay
HABITAT: forest, near water
SIZE: body: 60-79 cm (23.5-31 in)
tail: 2.5 cm (1 in)



The nocturnal pace is usually a solitary animal. It spends its day in a burrow, which it digs in a riverbank, among tree roots or under rocks, emerging after dark to look for food. The pace enters water willingly and will often escape from predators by swimming. It is believed to produce two litters a year of 1, rarely 2, young.

NAME: Brazilian Agouti, Dasyprocta aguti
RANGE: Venezuela, E. Brazil; Lesser Antilles
HABITAT: forest, savanna
SIZE: body: 41-62 cm (16-24.5 in)
tail: 1-3 cm (0.5-1.25 in)



Agoutis are social animals and are active in the daytime. They are good runners and can also jump up to 2 m (6.5 ft) vertically, from a standing position. Agoutis dig burrows in a riverbank or under a tree or stone and tread well-defined paths from burrows to feeding grounds. They are believed to mate twice a year and bear litters of 2 to 4 young.

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Copyright 1996 M. E. Barr.


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