- Northern Viscacha (Lagidium peruanum)
- Southern Viscacha (Lagidium viscacia)
- Wolffsohn's Viscacha (Lagidium wolffsohni)
- Lagidium ahuacaense - a new species from Ecuador described in June 2009.
The number of species of mountain viscachas is considered to be 3 by most authors: Lagidium peruanum (northern or montane viscacha), L. viscacia (southern or mountain viscacha), and L. wolffsohni (Wolffsohn’s viscacha). However, taxonomy usually differs by authors (e.g. L. peruanum is included within L. viscacia according to Anderson 1997).
Geographic Range, Habitat, and Ecology
The northern viscacha (Lagidium peruanum) occurs in the central and south Peru, and northern Chile. The distribution is shown to be the Andes mountain in Peru at elevations ranging between 3,000 to 5,000 m L. peruanum naturally occurs in Chile and Peru.
The southern viscacha (Lagidium viscacia) occurs in southern Peru, southern and western Bolivia, northern Chile and western Argentina. They occur between 2,500 m to 5,100 m above sea level.
Little data has been found about Lagidium wolffsohni.
Habitat and Ecology
L. peruanum prefers dry, rocky, habitats between the timber line and snow line of the Andes mountains with sparse vegetation and coarse grasses. It is an herbivorous species and is found near water that offers better vegetation than the drier regions within their habitats.
L. viscacia inhabits rocky mountain areas as well as rock outcrops in steppe habitat. They are restricted to sparsely vegetated, rocky habitats from 2,500 to 5,100 m above sea level. This herbivorous species is specialized and restricted to rocky habitats where it colonizes rock crevices and also associate themselves with available habitat that is patchy.
In large, steeper portions of the cliffs were more heavily used than less steep portions. Habitat use both on and away from the cliffs appears to be driven by predator avoidance. They can probably more easily escape terrestrial predators on a steep slope. They rarely venture away from rocks which provide a means for escape from both aerial and terrestrial predators.
Members of this species are medium to large-sized rodents which also looks remarkably like a long-tailed rabbit. Soft dense fur covers its body, from the tips of its elongate fur covered ears, edged with a fringe of white fur to the end of its long, curled tail. Their tails are bushy and can range up to about 1/3 of the length of its body. The forelimbs are relatively short, while the contrastingly long and muscular hind-limbs enable it to run and jump with ease. However, the number of digits on the hind feet is reduced to 4 (apparent in Chinchillas as well). The color of its fur varies seasonally and with age, but generally the upper parts are grey to brown, with tints of cream and black, while the under-parts are pale yellow or tan. However, contrary to the former statement, it has been stated elsewhere that they have pale yellow or grey upper parts, and a black tail tip. They weigh up to 6.6 lbs (3 kg) and have fairly delicate incisors in which the enamal of the incisors are not colored.
L. peruanum are diurnal species that are active throughout the year. They leap among rocks and performs a series of whistles and trills associated with warning. Colonial structures are composed of small family units of two to five individuals in a subdivided colony that can be as large as 75 animals.
L. viscacia are also diurnal and are most active near sunrise and sunset. They spend the day on perches, grooming and summing themselves. They are adept at moving over rocky surfaces and do not hibernate (unknown found information as to why).
In northern viscacha (L. peruanum), males tend to be promiscuous. The gestation period for the female is 140 days, and the usual litter size is one. It is viviparous and lactation takes about eight weeks. In Peru, mating takes place from October through November. Both female and male sexual maturities are reached after one year and weaning has been found to occur after 59 days.
In southern viscacha (L. viscacia), mating occurs from October through December. After a gestation of 120–140 days, a female gives birth to a single, precocious (having developed certain abilities or proclivities at an earlier age than usual) young. The young are born fully furred, with their eyes open, and are able to eat solid food on their first day of life. 
As previously mentioned, they are an herbivorous species. Their diet is principally composed of grasses, mosses, and lichens.
Not much is known about the longevity of these animals. Records show they live about 19.5 years in captivity.
Southern viscacha is often hunted for its meat and fur but it is still a very common species. Its population is not thought to be declining at a rate to warrant significant concern.
The genus of Lagidium, as a whole, is listed to be of "least concern" on the red list category due to the fact that it occurs in multiple protected areas and is restricted to rock formations. However, there is a deficiency in data.
- Ledesma, K. J.; Werner, F. A.; Spotorno, A. E.; Albuja, L. H. (2009-06-05). "A new species of Mountain Viscacha (Chinchillidae: Lagidium Meyen) from the Ecuadorean Andes". Zootaxa 212: 41–57. Retrieved 2010-06-18.
- Spotorno, A. (2004). "Molecular Divergence and Phylogenetic Relationships of Chinchillids (Rodentia: Chinchillidae)". Journal of Mammology 2004 : Vol. 85, Issue 3, pg(s) 384.
- "Lagidium viscacia". IUCN Red List. The IUCN Red List of Threatened Species. 2011. Retrieved 30 November 2011.
- Walker, RS (2000). "Habitat use by mountain vizcachas (Lagidium viscacia Molina, 1782) in the Patagonian steppe". Zeitschrift Fur Saugetierkunde-International Journal of Mammalian Biology 2000 : Vol. 65, Issue 5, pg(s) 293-300.
- "Chinchillidae". ZonotriKia. ZonotriKia. 1997. Retrieved 30 November 2011.
- "Lagidium viscacia-Southern Viscacha". EOL. EOL Encyclopedia of Life. 2009. Retrieved 30 November 2011.
- de Magalhaes, J. P., and Costa, J. (2009) "A database of vertebrate longevity records and their relation to other life-history traits." Journal of Evolutionary Biology 22(8):1770-1774.
- Hutchins, M. 2004. Viscachas and chinchillas. GRIZMEK’S ANIMAL LIFE ENCYCLOPEDIA 2ND EDITION, Vol. 16, pp. 377-384.
- Grzimek, B. 1990. Rodentia: Chinchillas. GRIZMEK’S ENCYCLOPEDIA OF MAMMALS, Vol. 3, pp. 320-321.
- Dunnum, J; Vargas, J; Bernal, N; Zeballos, H; Lessa, E; Ojeda, R. & Bidae, C. 2008. Lagidium viscacia. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 5 January 2009.