Squirrels of the World

Iomys sipora 107

natural history: The Javanese fl ying squirrel is reported
to feed on fruits, but details of its diet throughout the year
are unknown. This nocturnal species relies on nest cavities
and, although I. horsfi eldii is common in parts of its range,
little is known about this species’ behavior and ecology.
Studies of limb allometry show that the limbs of I. horsfi eldii
deviate signifi cantly from regressions based on data from
numerous rodent species, suggesting specifi c adaptations
for locomotion. The tail length, relative limb length, and
overall wing loading are lowest in smaller-bodied fl ying
squirrels like the Javanese fl ying squirrel. Hence smaller fl y-
ing squirrels show greater maneuverability when gliding.

general references: Aplin and Lunde 2008; Bou et al.
1987; Corlett 1992; W. P. Harris 1944; Lim et al. 1999; Med-
way 1966; Muul and Liat 1971; R. W. Thorington and Heaney
1981; R. W. Thorington and Santana 2007; Waterhouse 1838.

Iomys sipora (Chasen and Kloss, 1928)

Mentawai Flying Squirrel

description: This species is dark brown on the back, with
an even darker (almost black) tail. It is paler ventrally. The
ears are naked. Females have two pairs of inguinal nipples.

size: Female—HB 179.5 mm; T 179.5 mm.
Male—HB 196.0 mm; T 175.0 mm.

distribution: The Mentawai fl ying squirrel is found only
in a few locations on two islands in the Mentawai Archi-
pelago of Indonesia: Sipora and North Pagai.

geographic variation: None.

conservation: IUCN status—endangered. Population
trend—decreasing.

habitat: I. sipora resides in mature subtropical and tropical

forests, at elevations below 500 m.

natural history: Recent surveys have failed to detect

this species, and it is assumed to be on the decline, due to

extensive habitat loss as a result of various forms of agricul-

ture, human development, and timber harvests. Nothing is

known about the behavior, ecology, and reproduction of

this species.

general references: Mercer and Roth 2003; Ruedas et al.

2008d; R. W. Thorington and Darrow 2000; R. W. Thoring-

ton, Pitassy, et al. 2002.