Japanese dwarf flying squirrel

The Japanese dwarf flying squirrel (Pteromys momonga) is one of two species of Old World flying squirrels in the genus Pteromys, the other being Pteromys volans. It lives in sub-alpine and boreal evergreen forests on the Japanese islands of Honshu, Kyushu and Shikoku. Its body is 14 to 20 centimetres long with a tail of 10 to 14 centimetres, and it weighs 150 to 220 grams, far less than the Japanese giant flying squirrel, which can reach 1,500 grams. The back is grey-brown, the belly is white, the eyes are large and the tail is flattened. A gliding membrane, the patagium, spans the wrists to the ankles but not the hind legs and tail. It is nocturnal, resting by day in tree holes, usually in conifers such as pine and spruce, and it lines its nests with moss and lichen. It eats seeds, fruit, leaves, buds and bark, and it mates twice a year between May and July, with litters of two or three young. The IUCN lists it as least concern and its population trend is unknown.