Order : PRIMATES
Family : Cercopithecidae
Species : Presbytis siamensis

Head-body length : approx. 50 cm
Tail length : approx. 70 cm
Weight : maximum approx. 6.5 kg

Formerly considered a subspecies of the Banded Surili (Banded Leaf Monkey), the White-thighed Surili is now classified as a species in its own right.

The species is slender in build, with greyish or brownish-grey fur which becomes light grey to whitish on the underside and around the cheeks. Juveniles have distinctive spiked fur on top of the head. The eyes are framed by light fur/skin beneath and a line of pale fur at the side. The tail is dark.

Social groups of the species comprise an adult male, several females, juveniles and young. They feed on young leaf shoots, seeds and forest fruits.

Shown here (Figs 1 to 3) is the P. s. siamensis subspecies, which is common in the extensive sub-montane forests of central Peninsular Malaysia (the range of this subspecies also extends into southern Thailand).

Also shown (Fig. 4) is a rare image of the P. s. rhionis subspecies from Bintan Island, Riau Archipelago, Indonesia.

Other subspecies of the White-thighed Surili occur in parts of eastern Sumatra.

Figs 1 to 3 : Examples of P. s. siamensis in lower montane forest habitat.

Fig 4 : Rare photo of  P. s. rhionis, from Bintan Island, Riau Archipelago, Indonesia.


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