Squirrels of the World

Sundasciurus hoogstraali 185

size: Female—HB 234.9 mm; T 246.6 mm; Mass 432.7 g.
Male—HB 247.4 mm; T 234.9 mm; Mass 429.9 g.
Sex not stated—HB 235.2 mm; T 230.5 mm; Mass 363.0 g.

distribution: The horse-tailed squirrel is found in the
southern Malay Peninsula (Thailand and peninsular Malay-
sia), Sumatra (Indonesia), and the island of Borneo (divided
among Malaysia, Brunei Darussalam, and Indonesia).

geographic variation: Seven subspecies are recognized.

S. h. hippurus—range not known. See description above.
S. h. borneensis—Kalimantan (Indonesia), in ranges not oc-
cupied by S. h. hippurellus. This form has brick red under-
parts, and it is heavily grizzled gray on the shoulders and
thighs. The tail is entirely dark, and thick and bushy.
S. h. hippurellus—coasta l areas, in West Ka limantan (Indone-
sia) and at Sungai (= stream) Kapuas and Sungai Landak
through Sarawak to the lower Sungai Rejang (Malaysia).
The underparts are dark reddish; the tail is entirely dark
and is thick and bushy, but not very similar to that of a
horse. In some individuals the tail has a reddish tip.

S. h. hippurosus—west coast of Sumatra (Indonesia). This is a

larger form.

S. h. inquinatus—ranges from Lawas in northern Sarawak

(Malaysia) to Sungai Sebuku and Sungai Sembakung in

northern East Kalimantan (Indonesia). The underparts

are a dull orange.

S. h. ornatus—Minh Hai (= Cà Mau) Province (Vietnam). The

sides of the head, the shoulders, the upper surfaces of the

limbs, and the rump are grayish brown suff used with

ochraceous on the fl anks. The mid-dorsal area is washed

with rufous in the anterior part, and the posterior part

is glossy red brown bordered thinly with orange brown.

The underparts are bright chestnut. The tail is dark brown

on the basal third, and the tip is red.

S. h. pryeri—at low elevations throughout Sabah (Malaysia).

This form has white underparts that are tinged with red

in some individuals, and the tail is grizzled.

conservation: IUCN status—near threatened. Population

trend—decreasing.

habitat: On the Malay Peninsula, it is confi ned to tall and

secondary forests. It is found from the undercanopy to the

ground, at elevations ranging from the lowlands to the hills of

the main range, being recorded at 1006 m on Gunong (= Gu-

nung, or Mount) Tahan. Usually S. hippurus is seen a s a solita r y

individual or in pairs. On the island of Borneo it has been ob-

served throughout the lowlands and the hills, except in South

Kalimantan and the eastern parts of Central Kalimantan (In-

donesia); there are also some records from higher elevations,

such as at 1524 m on Mount Dulit in Sarawak (Malaysia).

natural history: The horse-tailed squirrel is diurnal.

Most often it is seen in small trees, but it sometimes travels

on the ground. Its diet includes seeds, fruits, and insects.

The most commonly occurring call is “chek... chek...

chekchekchekchek.. .”

general references: Medway 1969, 1977.

Sundasciurus hoogstraali (Sanborn, 1952)

Busuanga Squirrel

description: The sides are colored clay to tawny olive.

The dorsum is darker than the sides, due to the dark-colored

bases of the hairs and the presence of black hairs. The base

of the tail is similar to the back. The face is grayish, and the

hands and feet are dark brown. The underparts are paler,

due to the presence of long grayish white hairs.

Sundasciurus hippurus. Photo courtesy Con Foley.