The Small Japanese Field Mouse uses its long tail to move along branches and stores acorns in the soil in autumn for later food.
Its tail is slightly longer than its head and body, and it is smaller than the large Japanese field mouse. Juveniles of that larger species can be difficult to distinguish; skull shape helps with identification.
It balances with its long tail while walking along branches. In autumn it stores acorns in the soil; some uneaten acorns may sprout and contribute to forest renewal.
An extinction-risk assessment has not been added yet.