The Japanese giant flying squirrel (ムササビ musasabi, Petaurista leucogenys) is a species of flying squirrel, one of two species of Old World flying squirrels. It is native to Japan where is inhabits sub-alpine forests and boreal evergreen forests on Honshu, Shikoku and Kyushu islands. It grows to a head-and-body length of 50 cm (20 in) with a tail nearly as long again, and has a membrane connecting its wrists and ankles which enables it to glide from tree to tree. It feeds mainly on fruits and seeds. It breeds once a year in the autumn, with one or two young being born in its den. This squirrel faces no particular threats, has a wide range and is relatively common, and the International Union for Conservation of Nature lists it as being of "least concern".