The Japanese giant flying squirrel (Petaurista leucogenys) is a large species of flying squirrel that lives in sub-alpine and boreal forests. It is active at night and able to glide (not actually fly like a bat) long distances between trees by spreading out its patagium, skin between its limbs.
The Japanese giant flying squirrel has a web of skin between its legs which it uses to glide between trees. The tail is used for stability during flight. The body is about 25-50 cm long, and the tail a further 30-40 cm. It weighs between 700 and 1500g. It is much larger than the related Japanese dwarf flying squirrel which does not exceed 220g.
These flying squirrels are found only in Japan, where they prefer to live in sub-alpine forests and boreal evergreen forests on the islands of Honshu, Shikoku, and Kyushu. They can sometimes occur in plantations and urban areas.
Japanese giant flying squirrels are arboreal and glide from one tree to another searching for food. They can glide between trees up to 160 meters and almost never come to the ground. Japanese giant flying squirrels can live singly or in small groups. They are usually territorial, especially during the breeding season. The female has a home range of about a hectare and the male about two hectares. These flying squirrels are active at night and during the day rest in branches or hide in holes in large trees.
Japanese giant flying squirrels are herbivores (frugivores, granivores, folivores, lignivores). They eat fruit, grains, nuts, wood, bark, leaves, and flowers.
Japanese giant flying squirrels are thought to be monogamous and have only one mate during the breeding season. From winter to early summer the males compete for females. After the gestation period that lasts about 74 days, the female gives birth to one or two young in early autumn. The young usually remain in their nests for 59 or more days and begin foraging independently when they are 80 days old. They become completely independent at 12-18 months of age and become reproductively mature when they are around 21 months old. Young females often leave their natal territories before they reach reproductive maturity.
There are no major threats to this species at present.
According to the IUCN Red List, the Japanese giant flying squirrel is common throughout its range but no overall population estimate is available. Currently, this species is classified as Least Concern (LC) on the IUCN Red List.