Iomys horsfieldii

113.

Javanese Flying Squirrel

Iomys horsfieldii

French: Polatouche de Horsfield / German: Horsfield-Gleithornchen / Spanish: Ardilla voladora de Java

Taxonomy. Pteromys horsfieldii Waterhouse, 1838,

“Either from Java or Sumatra.”

Restricted by F. N. Chasen in 1940 to Sumatra, Indonesia.

Four subspecies are recognized.

Subspecies and Distribution.

I. h. horsfieldii Waterhouse, 1838 — Sumatra and Java. I. h. davisoni Thomas, 1886 — Malay Peninsula and Tioman I (off SE Malay Peninsula). I. h. penangensis Chasen, 1940 — Penang I (off NW Malay Peninsula). I. h. thomson: Thomas, 1900 — Borneo.

Descriptive notes. Head-body 165-231 mm, tail 159-207 mm; weight 120-231 g. Upper parts of nominate horsfieldii

are rufous brown, and underparts are yellow or yellowish white. Underside oftail is bright rust. Margin of flank skin and sides of face below eyes are reddish yellow. Subspecies davisoni is dark slate-gray on back, with rufous orange hair tips, and edges of sides are lined with rich orange. Tail is rich brown above and rich rufous orange below. Subspecies penangensis is similar to davisoni, butit is lighter and brighter on dorsal surface, forepaws,feet, and tail. Upper parts and head of thomsoni are dark smoky brown, grizzled with dull buffy white; undersides are whitish or pale fulvous.

Habitat. Forest stands ofall ages, disturbed and scrub vegetation, forest edges, plantations, and gardens. The Javanese Flying Squirrel appears to be less common in dense forests;it generally occursat elevations below 1000 m but can be found up to 1800 m.

Food and Feeding. The Javanese Flying Squirrel feeds on seeds and fruits. It can be a pest in cultivated fruit or coconut plantations.

Breeding. The Javanese Flying Squirrel is thought to have 1-4 young/litter, with an average of two.

Activity patterns. The Javanese Flying Squirrel is nocturnal.

Movements, Home range and Social organization. Javanese Flying Squirrels have the greatest maneuverability when gliding. They generally nest in tree cavities.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Current population trend of the Javanese Flying Squirrel is stable, and there are no major threats identified. It is protected in Indonesia and occurs in protected areas acrossits distribution. More surveys and basic research on its distribution, population status, and natural history are needed to better understand threats and useful conservation action. Habitat changes that limit connectivity are detrimental due to its unwillingness to travel on the ground and limited glide distance.

Bibliography. Aplin & Lunde (2008e), Bou et al. (1987), Chasen (1940), Corlett (1992), Harris (1944), Jackson (2012), Jackson &Thorington (2012), Lim et al. (1999), Medway (1966), Muul & Liat (1971), Thorington & Heaney (1981), Thorington & Santana (2007), Thorington et al. (2012), Waterhouse (1838).