The Malagasy mountain mouse is nocturnal and solitary and produces litters of up to three offspring. It is scansorial, spending time on the ground but also climbing in vegetation. In Andringitra, two specimens were captured on a liana over the ground, and a third was caught on the ground together with two shrew tenrecs (Microgale taiva). All five specimens from Andohahela were trapped on the ground, as was the specimen caught in Ankaratra in 1996. Its diet includes fruits and seeds; in captivity, it eats Agauria fruits.