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. 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. Reproduction Lagostumus maximus is capable of breeding throughout the year in captivity.