Japanese Giant Flying Squirrel

Description: A large flying squirrel with drab, greyish-brown fur above and whitish underparts, washed with buff. It has a whitish muzzle, dark rufous patches below its eyes, and snowy white cheek patches.

Distribution: Restricted to Japan on the islands of Kyushu, Shikoku and Honshu. It inhabits broad-leaved or mixed forest with evergreen and deciduous trees, including many big trees such as Japanese Cedar (Cryptomeria japonica), Japanese Zelvova (Zelkova serrata), Camphor Laurel (Cinnamomum camphora), Japanese Chinquapin (Castanopsis cuspidata) and oaks (Quercus spp.).

Reproduction: It has two mating seasons, one from mid-November to mid-January and a second from mid-May to mid-June. After a gestation period of 74 days, one to four (usually two) young are born from early February to early April and late July to late August.

A male will mate with two to four females and it appears the mothers allow their young to remain with them for a year to 18 months, until they become sexually mature. Males appear to be sexually mature at 21–22 months of age and females after at least 9–10 months of age.

Diet: Includes seeds, leaves, conifers cones, buds, fruits, angiosperm flowers and woody parts. It feeds on the young and mature leaves and buds from a variety of trees including maple (Acer sp.), horse chestnuts (Aesculus sp.), Camphor Laurel, beech (Fagus sp.), plums (and relatives; Prunus sp.), oaks (Quercus spp.) and elm (Zelkova sp.).

It feeds also on fruits, seeds and nuts from maple, camellia (Camellia sp. and Eurya sp.), camphor laurel, Japanese Cedar, beech, walnut (Juglans sp.), Japanese Persimmon (Diospyros kaki), avocado (Persea sp.), plums (and relatives), oaks, torreya (Torreya sp.), linden (Tilia sp.) and elm.

It takes flowers and buds from cypress (Chamaecyparis sp.), camellia, plums and relatives, and oaks; bark from avocado and plums; galls and bark from Japanese Cedar; winter sprouts from maple, camphor laurel, larch (Larix sp.), magnolia (Magnolia sp.), plums, oaks and elms. It also eats lichen. Because the species causes significant damage to plantation trees it has been shot or trapped, leading to its extermination in some parts of Japan.

Ecology: Nests in tree hollows but will nest on branches if suitable natural tree hollows are scarce, with a strong preference for the bark of the Japanese Cedar as a nest material. Rotates between a number of dens after a period of several days to several months. A given nest can be used successively by several individuals.

Females are territorial and rarely intrude into adjacent female territories. Home ranges overlap totally between the sexes, considerably between males but non-overlapping between females. The home range size varies from 0.46–2.68 hectares in females and from 0.78–5.16 hectares in males, depending on distribution pattern of food and nesting sites.

Predators possibly include the Red Fox (Vulpes vulpes), weasels (Mustela sp.) and martens (Martes sp.). There are recorded observations of Japanese Macaques (Macaca fuscata) attacking solitary flying squirrels. In captivity and in the wild the longevity appears to be approximately 10 years.

Status: Least Concern.