The plains viscacha exists in extreme southwestern Paraguay, northern and central Argentina, and southern Bolivia. (Nowak 1991)

Biogeographic Regions: neotropical (Native )

Lagostomus maximus is the largest member of the chinchilla family. Its combined head and body length measures 470-660 millimeters and its tail length is 150-200 mm. The color of the pelage of the animal is well correlated with the environment. The fur on its dorsal side is light brown in sandy areas and dark grey in regions where the soil is dark. The ventral surface is white. The tail is completely covered in fur. Guard hairs along the back of the animal are dark and coarse and contrast with the thick soft underfur. Unlike many other rodent species, L. maximus have a distinctively marked face. The head is large and blunt. Broad black and white stripes run along the animal's face. The rhinarium is furred and intricately folded. The forefoot contains four digits from which sharp stout claws extend. The amimal uses its claws for digging and its nose to push the dirt out. The hindfoot contains a pad of stiff bristles.

Lagostomus maximus exhibits strong sexual dimorphism. Males can be four times as massive as females. Both sexes have mustache-like whiskers, but this feature is much more pronounced in males.

(Branch 1994), (Nowak 1991)

Range mass: 2.000 to 8.000 kg.

Average basal metabolic rate: 10.623 W.

• Terrestrial

Lagostomus maximus inhabits grasslands and lowland desert scrubs. The animal also constructs burrow systems in the barren parts of pampas at an elevation of 2,680 meters. (Nowak, 1991)

Terrestrial Biomes: desert or dune

The species is herbivorous. In captivity, it consumes almost any kind of vegetation. In the wild, the animal feeds on seeds and grass, mainly Medicago minima and Erodium cicutarium. (Branch 1993), (Nowak 1991)

Primary Diet: herbivore (Folivore , Granivore )

Average lifespan

Status: captivity: 9.4 years.

Average lifespan

Status: captivity: 9.0 years.

Lagostumus maximus is capable of breeding throughout the year in captivity. In the wild when conditions are favorable, two litters are produced annually. However, plains viscachas in east-central Argentina have a single breeding season in which mating occurs in March-April and births in July-August. The reproductive pattern of female plains viscacha is distinctive in that many ova are shed to produce only a litter of two. Sectioning of the reproductive tract by Weir (1971) established 50-845 ova released by the female. Up to seven embryos implant in the uterus of the female and development continues for 30 days. By the 90th day, all but the most caudally situated embryos in the uterine horn are resorbed.

Females have an estrous cycle of 45 days. The gestation period lasts 145-154 days. The number of individuals in a litter is usually two, but the range is one to four. When born, the young are precocial and fully furred, weighing approximately 200 grams. Females lactate for a minimum of 21 days, but the young are usually weaned after eight weeks. Females reach sexual maturity at 8.5 months and males at 15 months.

(Birney and Day-Baird 1985), (Branch 1993), (Branch, Villarreal and Fowler 1994), (Nowak 1991)

Range number of offspring: 1.000 to 4.000.

Average number of offspring: 2.000.

Range gestation period: 145 to 166 days.

Average gestation period: 153.7 days.

Range weaning age: 54.000 (high) days.

Average birth mass: 200 g.

Average number of offspring: 2.

Average age at sexual or reproductive maturity (male)

Sex: male: 456 days.

Average age at sexual or reproductive maturity (female)

Sex: female: 258 days.

Parental Investment: precocial

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CITES: no special status

IUCN Red List of Threatened Species: least concern

The species is considered to be a pest to farmers. It raids cultivated crops and construct burrows large enough to cause cattle to stumble and break bones. Although unconfirmed, there are claims that the animal's acidic urine devalues the soil for many years. Recent extirpation campaigns of L. maximus by humans have greatly reduced the population of the species. (Nowak 1991)

Lagostomus maximus has been a source of meat and fur for humans. (Nowak 1991)

Positive Impacts: food ; body parts are source of valuable material