Octomys mimax (Rodentia: Octodontidae)

Octomys mimax O. Thomas, 1920, the viscacha rat, is a surface-dwelling rodent, endemic to the Monte biome of western Argentina. The genus Octomys is monotypic and represents a basal clade within the family Octodontidae. O. mimax is strictly herbivorous and is found in low-elevation arid environments characterized by galleries or rock formations. In these environments, O. mimax nests within rock crevices located inside ravines with relatively low vegetation cover. O. mimax is solitary and mostly nocturnal. Nocturnal activity coupled with a basal metabolic rate and thermal conductance lower than expected for body mass of O. mimax probably represent strategies for water conservation in this species.