182 Rubrisciurus rubriventerfossil records of its presence in this part of the island in
prehistoric times.
geographic variation: None.
conservation: IUCN status—vulnerable. Population
trend—decreasing.
habitat: The Sulawesi giant squirrel is found from the
coast up to an elevation of 1512 m, in primary tropical low-
land evergreen forests and in lower montane rainforests.
natural history: This squirrel is diurnal, arboreal, and
terrestrial. R. rubriventer forages and travels in the under-
story and on the ground, never in the canopy or higher. It
nests in the forest understory. There is anecdotal evidence
that the nests are large globular structures made from plant
matter and built close to the ground in the cavities of large
tree trunks. One nest, located by Musser and his team, was
30 cm in diameter, wedged in a hollow of a tree (Pterosper-
mum celebicum), and constructed entirely of the long black
fi bers of the sugar palm (Arenga pinnata). Their diet is com-
posed of fruits, seeds, and insects. These squirrels are known
to be quiet, wary, and easily startled; sometimes the only
evidence of their presence is the sound of loud gnawing on
the fruit of the pohon pangi (Pangium edule). The skull mor-
phology suggests that they are able to consume hard nuts
and seeds. They also dig into rotting wood to expose insects.
A single embryo has been observed in the few pregnant fe-
males caught. Females have four teats, arranged in pairs.general references: Musser et al. 2010.Sundasciurus Moore, 1958
This is a genus of 17 species of small to medium-sized South-
east Asian squirrels.
Sundasciurus altitudinis (Robinson
and Kloss, 1916)
Sumatran Mountain Squirrel
description: Sundasciurus altitudinis is very similar to S.
tenuis, but with much longer fur, more yellowish hands and
feet, and a light gray hue on the underparts. There are tren-
chant diff erences in the skull anatomy of S. altitudinis, in-
cluding the small size of the bullae and the longer rostrum.
size: Sex not stated—HB 150 mm; T 115 mm.
distribution: This species occurs in the highlands of Su-
matra (Indonesia), at elevations ranging from 488 to 2530 m
or higher, in Atjeh (= Aceh) and Padang (on Mount Löser and
on Kerinci Peak, respectively).
geographic variation: None.
conservation: No information is available.
habitat: The Sumatran mountain squirrel is only found “in
heavy jungle... at any level from low in the bushes to high
in the very tops of tall trees” (den Tex et al.).
natural history: They feed on “curious acorn-like nuts
that the natives call ‘giseng’ ” (den Tex et al.).general references: den Tex et al. 2010.