Viscachas or vizcachas are rodents in the chinchilla family Chinchillidae.
There are two genera and four species of viscacha.
- Plains viscacha (Lagostomus maximus): Resident of the Pampas of Argentina, easily differentiated from other viscachas by black and gray mustache-like facial markings. This species lives colonially in warrens of ten to over one hundred. It is very vocal and emits alarm calls. The plains viscacha can strip grassland used to graze livestock; this caused ranchers to consider the rodent a pest species.
- Northern viscacha (Lagidium peruanum): Native to the Peruvian Andes at those elevations between the tree line and the snow line. It is dorsally gray or brown in color, with a bushy tail and long, furry ears. This species lives in large colonies separated into individual family units, like an apartment complex. It eats a wide range of plant matter, settling for almost anything it can find growing in the harsh, rocky environment. An individual which has tentatively been assigned to L. peruanum has been discovered in Ecuador, and may represent a distinct species (Werner et al., 2006).
- Mountain viscacha (Lagidium viscacia): Also called southern viscacha, this species is similar to the northern viscacha, but its pelage is more red in color. It lives in similar habitat in the Andes.
- Wolffsohn's viscacha (Lagidium wolffsohni): Little is known about this species, as it is rarer than the other three viscachas.
- Werner, F. A., K. J. Ledesma, and R. Hidalgo B. 2006. Mountain vizcacha (Lagidium cf. peruanum) in Ecuador - First record of Chinchillidae from the Northern Andes. Mastozoología Neotropical, 13:271-274.