The body form is not modified for fossorial life, and the tail is bushy. This genus resembles Octodontomys externally, but the reentrant folds of the upper molars in Octomys meet in the middle of the teeth. Viscacha rats appear to be rare and are difficult to trap. There is no evidence that the scarcity has been caused by human agency. These rodents spend the day sleeping in their burrows.
Females produce several litters per year.
A pregnant female was captured on 12 December 1987.