Chinchillidae

Diversity

The family Chinchillidae includes 7 currently recognized species divided into two subfamilies: Lagostominae and Chinchillinae . The subfamily Lagostominae includes one genus ( Lagostomus ) with one extant species: Argentine plains viscachas ( Lagostomus maximus ). The subfamily Chinchillinae includes two genera: Chinchilla and Lagidium . There are two extant species within the genus Chinchilla : short-tailed chinchillas ( Chinchilla chinchilla ) and long-tailed chinchillas ( Chinchilla lanigera ). Within the genus Lagidium there are four extant species: northern mountain viscachas ( Lagidium peruanum ), southern mountain viscachas ( Lagidium viscacia ), Wolffsohn’s mountain viscachas ( Lagidium wolffsohni ), and Ecuadorian mountain viscachas ( Lagidium ahuacaense ).

Geographic Range

Members of the family Chinchillidae are native to the Neotropical region, primarily in the Andes Mountains, including parts of southern Peru, northern Chile, southwestern Bolivia, and western Argentina. However, Argentine plains viscachas live in the Pampas of South America, including central and eastern Argentina, southern Bolivia, and southern Paraguay.

• Biogeographic Regions
• neotropical neotropical
  • native native

Habitat

Chinchillas (genus Chinchilla ) and mountain viscachas (genus Lagidium ) live in the Andes Mountains at elevations between 3,000 and 5,000 m above sea level (asl). They establish dens in the crevices of rock piles. In contrast, Argentine plains viscacha ( Lagostomus maximus ) inhabit lower elevation grasslands and desert scrublands in the Pampas of South America, as high as 2,680 m asl. Argentine plains viscachas spend the day in burrows, called vizcacheras, and forage between dusk and dawn.

• Habitat Regions
• terrestrial terrestrial

• Terrestrial Biomes
• savanna or grassland savanna or grassland
• mountains mountains

Systematic and Taxonomic History

Chinchillas and viscachas are rodents (order Rodentia ). More specifically, they are hystricognaths (infraorder Hystricognathi ) within the suborder Hystricomorpha . Within Hystricognathi , they are part of the parvorder Caviomorpha , which includes all New World hystricognaths. The closest relatives of chinchillas and viscachas are chinchilla rats (family Abrocomidae ), which are included in a common superfamily, Chinchilloidea . Some researchers previously considered New World hystricognaths to be a polyphyletic group, but current molecular data supports the hypothesis that they are a monophyletic clade, defined as Caviomorpha .

Within the family Chinchillidae , there are two subfamilies: Chinchillinae and Lagostominae . The subfamily Lagostominae includes the genus Lagostomus , with only one extant species. The subfamily Chinchillinae includes the genus Chinchilla , which consists of two extant species, and the genus Lagidium , with 4 extant species. There were previously only three species recognized in the genus Lagidium , but genetic research in 2009 distinguished Ecuadorian mountain viscachas ( Lagidium ahuacaense ) from northern viscachas ( Lagidium peruanum ).

Physical Description

Chinchillas and viscachas have thick fur and slender bodies with short forelimbs and long, muscular hindlimbs with fleshy pads on their paws. Members of the genera Lagidium and Chinchilla have finer fur than members of Lagostomus . All members of the family Chinchillidae have four digits on their forefeet, but the number of digits on their hindfeet vary by genus. Members of the genus Lagostomus have three hind digits with powerful claws for digging, whereas members of the genera Lagidium and Chinchilla have four hind digits with comparatively weak claws. Their bodies range in length from approximately 23 to 66 cm, and their tails range in length from 7.5 to 40 cm. Some species in the family Chinchillidae exhibit size-based sexual dimorphism, although which sex is larger depends on the species.

All chinchillas and viscachas have a dental formula of I 1/1, C 0/0, P 1/1, M 3/3. Their teeth are lophodont and hypsodont, which is advantageous considering they eat exclusively plant material.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

Reproduction

The mating systems of species in the family Chinchillidae vary depending on genus, although they generally exhibit polygyny. In the genus Lagostomus , males often display increased aggression towards other males and disperse from the main colony when young are born. In the genus Lagidium , females become more aggressive while in estrus and drive males out of burrows. In the genus Chinchilla , females are highly aggressive towards other females and males throughout the year and will threaten conspecifics with behaviors such as chattering, urinating, and growling. All members of this family use vocalizations for communication, but physical fights between males during the breeding season is only reported in the genus Lagostomus .

• Mating System
• polygynous polygynous

In wild populations of chinchillas and viscachas, females undergo seasonal estrus cycles. However, some species are capable of breeding throughout the year in captivity. Some species in the family Chinchillidae experience postpartum estrus, and post-lactation estrus is common in the genus Lagostomus . The estrus cycle is an average of 38 days long in chinchillas (genus Chinchilla ), 57 days long in mountain viscachas (genus Lagidium ), and 45 days long in plains viscachas (genus Lagostomus ). The timing of the breeding season varies for distinct populations within species. The average age of sexual maturity is 8 months for chinchillas, 1 year for mountain viscachas, and 8.5 months for female plains viscachas, and 15 months for male plains viscachas. There are some claims that chinchillas are monogamous, but there is currently little evidence to support this claim.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous
• post-partum estrous

All members of the family Chinchillidae give birth to small litters of young, although average litter size varies between genera. Mountain viscachas (genus Lagidium ) have an average of 1 young per litter, whereas plains viscachas (genus Lagostomus ) have an average of 2 (range 1 to 4), and chinchillas (genus Chinchilla ) have an average of 2 or 3 (range 1 to 6). Offspring are precocial, and newborn mountain viscachas are even capable of eating solid foods.

Average gestation period is 111 days for chinchillas , 140 days for mountain viscachas , and 154 days for plains viscachas. Average weaning time for all members of the family Chinchillidae is typically around 8 weeks. Some species are capable of producing multiple litters per year, given favorable conditions. Both chinchillas and viscachas are social and live in colonies, so offspring typically end up living with their parents even after independence.

• Parental Investment
• precocial precocial
• female parental care female parental care
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • provisioning
    • female
  • protecting
    • female
• post-independence association with parents

Lifespan/Longevity

Life expectancy of chinchillas and viscachas varies by genus. Mountain viscachas (genus Lagidium ) typically live around 3 years in the wild, but captive individuals can reach up to 19 years of age. Plains viscachas (genus Lagostomus ) live 7 to 8 years in the wild, with one captive individual reaching over 9 years of age. Chinchillas (genus Chinchilla ) seem to be the longest lived members of the family Chinchillidae , with lifespans of approximately 10 years in the wild and over 20 years in captivity.

Behavior

Chinchillas and viscachas are highly social. They live in colonies that range in size from 4 to 75 individuals. Chinchillas (genus Chinchilla ) and mountain viscachas (genus Lagidium ) both live in montane environments, making communal dens in crevices between rocks. In contrast, Argentine plains viscachas ( Lagostomus maximus ) - the only extant member of the genus Lagostomus - live at lower elevations in grasslands or deserts and construct large underground burrows called viscacheras. They bring objects such as sticks, dried dung, and bones to their vizcacheras. The purpose of this behavior is not well understood, but it may be involved in scent marking, flood prevention, or protection from predators. All chinchillas and viscacheras are known to clean their fur and skin by taking dust baths.

• Key Behaviors
• terricolous
• fossorial fossorial
• saltatorial saltatorial
• nocturnal nocturnal
• crepuscular crepuscular
• motile motile
• sedentary sedentary
• social social
• colonial colonial

Communication and Perception

In chinchillas and viscachas, almost all intraspecific communication involves auditory or chemical signaling, including urinating, growling, teeth chattering, and other, more specific vocalizations. There is relatively little information regarding the communication methods of species in the family Chinchillidae due to recent population declines. Chinchillas and viscachas are typically not aggressive toward conspecifics except during the mating season.

• Communication Channels
• acoustic acoustic

• Other Communication Modes
• scent marks scent marks

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

All chinchillas and viscachas are herbivores. Their diets primarily consist of shrubs, forbs, and grasses, although the specific plant species in their diet vary depending on geographic location.

• Primary Diet
• herbivore herbivore
  • folivore folivore

Predation

Chinchillas and viscachas serve as prey for larger mammals, birds, and reptiles, although specific predators vary depending on geographic location.

Species in the family Chinchillidae have several adaptations to avoid predators, some of which are species-specific. For example, chinchillas (genus Chinchilla ) can release large patches of their fur to potentially escape predators that grab them. Also, Argentine plains viscachas ( Lagostomus maximus ) fill their burrow systems with sticks, dried dung, and bones, which likely makes it more difficult for predators to get in. All species the family Chinchillidae live in groups, which affords them further protection from predators. If an individual detects a predator nearby, they produce alarm calls to alert other members of their social group.

Ecosystem Roles

Members of the family Chinchillidae are herbivores that impact the densities of different plant species in their range. They also serve as sources of prey for large mammals, birds of prey, and reptiles.

In addition to their roles as herbivores and prey species, Argentine plains viscachas ( Lagostomus maximus ) also play a role as ecosystem engineers. They dig large burrow systems, called viscacheras, many of which support the same social group for multiple generations. During the construction of new viscacheras, Argentine plains viscachas may move upwards of 80 m^3 of soil. They also fill their viscacheras with objects, such as sticks, dung, and bones. Other animals, such as burrowing owls ( Athene cunicularia ) and lesser grisons ( Galictis cuja ) make use of both occupied and abandoned viscacheras.

• Ecosystem Impact
• creates habitat
• soil aeration soil aeration

Economic Importance for Humans: Positive

All members of the family Chinchillidae are traditionally hunted for meat and fur, but recent protections have been put in place to prevent poaching of wild populations. Long-tailed chinchillas ( Chinchilla lanigera ) are part of the pet trade and have also contributed to biomedical research; they have been used to study auditory systems because their hearing range is similar to humans and their tympanic bullae are easily accessible.

• Positive Impacts
• pet trade pet trade
• food food
• body parts are source of valuable material
• research and education

Economic Importance for Humans: Negative

There are relatively few negative economic impacts associated with species in the family Chinchillidae , since they primarily live in montane areas that are not near human settlements. However, Argentine plains viscachas ( Lagostomus maximus ) live in grasslands and may eat crop plants. Furthermore, their extensive burrow systems can disrupt farming practices or lead to injuries.

• Negative Impacts
• crop pest

Conservation Status

For many species in the family Chinchillidae there is a lack of information regarding conservation status. Both extant species of chinchilla (genus Chinchilla ) are endangered and are currently experiencing population declines due to habitat loss. Ecuadorian mountain viscachas ( Lagidium ahuacaense ) are listed as data deficient, but there is only one known population and the group of scientists that described the species advised they be listed as critically endangered. Wolffsohn's viscachas ( Lagidium wolffsohni ) are also considered to be data deficient by the IUCN Red List, but they are considered endangered in Argentina. Northern mountain viscachas ( Lagidium viscacia ) are listed as a species of least concern and their populations are currently considered stable. Argentine plains viscacha ( Lagostomus maximus ) are also listed as a species of least concern, but there is a notable lack of information on populations in large parts of their geographic range. There are no conservation measures in place for chinchillas or viscachas specifically. However, there is one known population of Wolffsohn's viscachas on protected and it is possible that the geographic ranges of other species include protected lands, such as national parks.

Additional Links

Encyclopedia of Life

Contributors

Riley Massiha (author), Colorado State University, Galen Burrell (editor), Special Projects.

References

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