Chinchilla Rats: Abrocomidae

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CHINCHILLA RATS: Abrocomidae

ASHY CHINCHILLA RAT (Abrocoma cinerea): SPECIES ACCOUNT

PHYSICAL CHARACTERISTICS

Chinchilla rats have large, round ears, large eyes, and an elongated head. They have short legs with four toes on the front feet and five toes on the back feet. The head and body length of the chinchilla rat is 6 to 10 inches (15 to 25 centimeters with a tail length of 2.4 to 7.2 inches (6 to 18 centimeters). They weigh from 7.1 to 10.6 ounces (200 to 300 grams).

The fur of the chinchilla rat is thick and soft. Fur coloring is silver-gray or gray-brown on the upper body and light brown, cream, white, or yellow on its underside.

GEOGRAPHIC RANGE

They are found from coastal areas to the Andes Mountains in southern Peru, northern Chile, northwest Argentina, and central Bolivia.

HABITAT

Chinchilla rats live in rock crevices and elaborate burrows under rocks or at the base of shrubs.

DIET

Chinchilla rats are herbivores, meaning they eat only plants. The feed at night on seeds, fruits, and nuts.

BEHAVIOR AND REPRODUCTION

There is very little scientific information on the behavior of chinchilla rats, due to their small population. Only a handful of research has been done on the small rodents. What is known has usually been gained by observing the behavior of only a few of each species.

Chinchilla rats live inside burrows in colonies of up to six individuals. Colonies are usually close together, sometimes as little as 59 feet (18 meters) apart. Little is known about the reproductive behavior of chinchilla rats. They usually mate in January or February. The gestation period, the length of time the female carries the babies in her womb, is 115 to 118 days. Litters are usually one or two babies.

There are four species: Bennett's chinchilla rat, which lives in the coastal foothills and high plains of the Andes Mountains in Chile; Bolivian chinchilla rat, which is found in central Bolivia; ashy chinchilla rat, found in the high plains of the Andes in Bolivia, Chile, and Peru; and Cuscomys ashaninki, which does not have a common name, found in Peru.

Cuscomys ashaninki was discovered in 1999 when a single dead body was found. As a result, there is virtually no information available on this species. The skeletal remains of another species, Cuscomys oblativa, have been found in Peru but the species is believed to be extinct.

Bennett's chinchilla rat sometimes shares burrows with similar-sized degus. A Bennett's chinchilla rat in captivity lived two years and four months. Their lifespan in the wild is believed to be one to two years.

CHINCHILLA RATS AND PEOPLE

Chinchilla rats are sometimes hunted by humans for their fur, which is sold at local fur markets and has a low value. It is sometimes sold to tourists as real chinchilla fur. They were hunted extensively for their fur in the early twentieth century and all species were nearly extinct by the 1920s when several South American countries passed laws to protect them.

ROCK CLIMBERS

Chinchilla rats love to climb and are extremely talented. Although they spend most of their time on or under the ground, they do climb rock outcroppings, plants, and trees. Sometimes they live within crevices of rocky cliffs. Often they will build sidewalls inside their rocky dens up to 10 feet (3 meters) high. They use a construction material made of their own feces and urine. When dry, the mixture is almost as hard as rock.

CONSERVATION STATUS

The Bolivian chinchilla rat is listed as Vulnerable, facing a high risk of extinction in the wild, due to its population being confined to a small area. The other chinchilla rats are not listed as threatened by the IUCN.

ASHY CHINCHILLA RAT (Abrocoma cinerea): SPECIES ACCOUNT

Physical characteristics: The head and body length of the ashy chinchilla rat is 6 to 10 inches (15 to 25 centimeters) with a tail length of 2.4 to 7.2 inches (6 to 18 centimeters). They weigh from 7.1 to 10.6 ounces (200 to 300 grams). They have large, round ears, large eyes, and an elongated head. They have short legs with four toes on the front feet and five toes on the back feet. The fur of the ashy chinchilla rat is thick and soft. Fur coloring is silver-gray on the upper body and cream, white, or yellow on its underside.

Geographic range: Ashy chinchilla rats live in the Altiplano, a high plateau area of the Andes Mountains, from southern Bolivia and Peru to central Chile.

Habitat: They are found in rocky regions of 12,000 to 16,400 feet (3,700 to 5,000 meters). They usually live in burrows under rocks or at the base of shrubs.

Diet: Ashy chinchilla rats are herbivores, meaning they eat only plants. They feed at night on seeds, fruits, and nuts.

Behavior and reproduction: Ashy chinchilla rats live in burrows in colonies of up to six individuals. Colonies are usually close together, sometimes as little as 59 feet (18 meters) apart. Little is known about the reproductive behavior of ashy chinchilla rats. They usually mate in January or February. The gestation period, the length of time the female carries the babies in her womb, is 115 to 118 days. Litters are usually one or two babies.

This species of chinchilla rat makes several vocal sounds, including a grunt when it is fighting or about to fight, a squeak when it is frightened, and a low gurgle when being groomed by one of its colony members.

Ashy chinchilla rats and people: Ashy chinchilla rats are sometimes hunted by humans for their fur, which is sold at local fur markets and has a low value. It is sometimes sold to tourists as real chinchilla fur.

Conservation status: The ashy chinchilla rat is not listed as threatened by IUCN. However, its population is believed to be low and in decline due to hunting and habitat destruction by humans. ∎

FOR MORE INFORMATION

Books:

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.

Wilson, Don E., and DeeAnn M. Reeder. Mammal Species of the World— A Taxonomic and Geographic Reference, 2nd ed. Washington, DC: Smithsonian Institution Press, 1993.

Periodicals:

Braun, Janet K., and Michael A. Mares. "Systematics of the Abrocoma cinerea Species Complex (Rodentia: Abrocomidae), with a Description of a New Species of Abrocoma." Journal of Mammalogy (February 2002): 1–19.

Huchon, Dorothée, and Emmanuel J. P. Douzery. "From the Old World to the New World: A Molecular Chronicle of the Phylogeny and Biogeography of Hystricognath. Rodents." Molecular Phylogenetics and Evolution (August 2001): 238–251.

Meserve, Peter, et al. "Role of Biotic Interactions in a Small Mammal Assemblage in Semiarid Chile." Ecology (January 1996): 133–148.

Meserve, Peter L., et al. "Thirteen Years of Shifting Top-Down and Bottom-Up Control." BioScience (July 2003): 633–646.