A small, agile species, the eastern puna mouse feeds primarily on plants, particularly Senecio adenophylloides and Werneria digitata. It is a remarkably dextrous rodent, able to manipulate and cut twigs as long as 50 centimetres with its stout incisors. The eastern puna mouse usually stores the cut twigs in a cache under a rock, sometimes storing as many as 30 twigs in one cache (2).
The eastern puna mouse is active during the day, when it will scurry from place to place in the shelter of rocks. This species is thought to breed during the dry season, possibly between June and September (2).