Chilean rock rats are fossorial and use their vibrissae to navigate within their extensive burrows. They sleep together in groups and have a system of vocal alarms if danger is present. Mothers vocally communicate with their young, and both sexes use the scent in their urine as chemical cues for colonial territoriality and individual recognition. "Outsiders" to colonies use intense vocalization and tail movements to discern territoriality.
Communication Channels: visual ; tactile ; acoustic ; chemical
Other Communication Modes: scent marks
Perception Channels: visual ; tactile ; acoustic ; vibrations ; chemical
Multiple internet sources claim Chilean rock rats are a critically endangered species. In fact, most claim the species is to be extinct within 6 years. However, Aconaemys fuscus was not found on the IUCN Red List, U.S. Federal List, or the CITES list. All internet sources researched were not produced by a governmental or research agencies and could not be deemed credible.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
This species is not considered to have any negative effects on humans. It is not considered an agricultural pest or household pest, and is not known to transmit disease to other economically important species or humans.
No economic importance determined to date.
Soil is disturbed and aerated through A. fuscus burrowing activities, which may promote seed germination. To a further extent, these animals also ingest a large number of seeds, which may aid in the dispersal of seeds via feeding activities and fecal droppings.
Ecosystem Impact: disperses seeds; soil aeration
Species Used as Host:
Mutualist Species:
Commensal/Parasitic Species:
Chilean rock rats feed nocturnally, primarily on grasses, grains, and foliage. Interestingly, they store tubers and grains in their burrows, but do not become dormant during the winter. They also re-ingest their own feces to maximize nutrient extraction from their food.
Plant Foods: leaves; roots and tubers; wood, bark, or stems; seeds, grains, and nuts
Other Foods: dung
Foraging Behavior: stores or caches food
Primary Diet: herbivore (Folivore , Granivore , Lignivore)
Chilean rock rats (Aconaemys fuscus), are endemic to Argentina and central Chile. Their distribution ranges from 33 degrees to 41 degrees south latitude. These animals are generally confined to the high, southern Andes mountain range. Historically (ca. 1,000 years ago), the distribution of Chilean rock rats extended to areas near Santiago, more than 100 km north of the species' current range.
Biogeographic Regions: neotropical (Native )
Chilean rock rats inhabit rocky outcrops on the high border of alpine Andean grassland, above tree- and shrub-line at moderate altitudes of the Andes mountain range. This habitat is characterized as arid, with little or no woody plant cover, and has snow cover approximately 3 months per year.
Range elevation: 1000 to 3500 m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: chaparral ; mountains
No data were found on the lifespan of Chilean rock rats. However, other members of the Octodontidae family, such as Octodon degus, have a expected lifespan of approximately 5 years. Aconaemys fuscus may be similar.
Chilean rock rats are similar in size and morphology to other members of the Octodontidae family. They are characterized as having large heads, pointed noses, moderately large and rounded ears, short tails, and long vibrissae on the face. Their legs are short; the forefeet have 4 digits, the hindfeet have 5 digits, and the toes end in sharp, curved claws. Their bodies are covered with long, dense, and silky fur with a well-developed underfur. Dense short hairs cover the tail, and a "comb" of stiff hairs extends slightly beyond the middle digits of the hind feet. Pelage is grayish over the back and a slightly paler gray on the belly.
The skull is relatively stout and angular in appearance. The angular process is highly deflected. The dentary has a prominant coronoid process. The zygomatic arch is simple, and the jugal does not contact the lacrimal. The bullae are fused to the short paroccipital processes. The dental formula is 1/1, 0/0, 1/1, 3/3. Incisors are well-developed, and molars are flat crowned, hypsodont, and distinctively "8"-shaped due to single labial and lingual folds.
Aconaemys fuscus ranges in weight from 30 to 67 g, has lengths between 100 and 140 mm. Within the genus Aconaemys, males reportedly weigh less than non-pregnant females.
Range mass: 0.030 to 0.067 kg.
Range length: 100 to 140 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: female larger
Details on predation of A. fuscus are not readily available. The pelage of these rodents is camoflaged with the rocky outcrops they inhabit. They are colonial and have a system of vocal alarms if danger is present, indicating that predation has been a factor in their evolutionary history. Despite the lack of information for this species we are able to infer something about predation based on related animals. Octodon degus, a member of same family (Octodontidae), which has a similar geographic range and is found in the same habitat as Chilean rock rats, is known to be preyed upon by both raptors and snakes. It is likely that these animals also eat A. fuscus.
Anti-predator Adaptations: cryptic
Chilean rock rats are thought to be polygynous and cooperative breeders.
Mating System: polygynous ; cooperative breeder
Chilean rock rat females have an average of 4 young per litter, yet retain 4 pairs of teats. The gestation period is around 75 days. Two litters may be produced over the breeding season which last from July to January. The eyes are closed at birth and the fur, although present, is thin. Eyes open at approximately 4 days of age, and young are weaned at approximately 60 days. Both females and males reach sexual maturity at 1 year.
Breeding interval: Aconaemys fuscus breeds twice yearly.
Breeding season: Breeding takes place betweem July and January.
Range number of offspring: 2 to 5.
Average number of offspring: 4.
Range gestation period: 70 to 80 days.
Average weaning age: 60 days.
Average time to independence: 60 days.
Average age at sexual or reproductive maturity (female): 1 years.
Average age at sexual or reproductive maturity (male): 1 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous
Newborn A. fuscus are precocial relative to many rodents, being fairly well developed at birth. Eyes open at a mere four days of age, and fur is present from birth. However, since the young cannot care for themselves, they are considered altricial. Chilean rock rat females living in the same burrow have been observed to nurse one another's young, and males have been observed to help raise the young.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Female, Protecting: Male, Female); pre-independence (Provisioning: Female, Protecting: Male, Female)
The Chilean rock rat (Aconaemys fuscus) is a species of rodent in the family Octodontidae.[2] It is found in the high Andes of Argentina and Chile.
The Chilean rock rat is a short-tailed rodent. Rock rats in the genus Aconaemys are similar to those in the genus Ctenomys but not so specialised for life underground. The ears are rather larger, the claws on the front feet which are used for digging are smaller, and the edging of hairs on the hind feet, used for shifting loose soil, is reduced in size.[3]
The upper parts of the Chilean rock rat are dark brown, with the underparts ranging from reddish brown to white. Sample specimens described in 1966 and 1984, from two different locations, had a head-and-body length ranging from 135 mm (5 in) to 187 mm (7 in), with the tail adding another 58 mm (2 in) – 80 mm (3 in) to the animal's total length.[3][4]
Its karyotype has 2n = 56 and FN = 108.[2]
This species is endemic to parts of Argentina and Chile in the high Andes in South America. Its range extends from about 33°S to 41°S. In Argentina, it is restricted to thick forests of bamboo and Nothofagus dombeyi, but in Chile it is found in monkey puzzle (Araucaria) and southern beech (Nothofagus) forests, and above the tree line, usually among tussocky grass.[3] It occurs up to about 4,000 metres (13,100 ft).[1]
The Chilean rock rat is a semi-fossorial species and constructs a network of shallow tunnels and runways with entrances every metre or so. These burrows resemble those of Spalacopus and Ctenomys and are sometimes also used by Akodon longipilis and Geoxus valdivianus. It seems to be a colonial species and feeds on roots and seeds, apparently specialising on the roots and seeds of Araucaria in Chile. It is mainly active by night but sometimes also by day. It stores food for use in winter when it is active, moving about under the snow.[3]
A. fuscus has a wide range and seems to be plentiful. No particular threats have been identified and the International Union for Conservation of Nature has assessed its conservation status as being of "least concern".[1]
The Chilean rock rat (Aconaemys fuscus) is a species of rodent in the family Octodontidae. It is found in the high Andes of Argentina and Chile.
