Thomas’s Langur

About the Thomas’s Langur

Thomas's langur (Presbytis thomasi), also known as the North Sumatran leaf monkey or Thomas's leaf monkey, is a species of primate in the family Cercopithecidae. It is endemic to northern Sumatra, Indonesia, not living to the south and east of Lake Toba and the Alas and Wampu rivers. Its natural habitat is subtropical or tropical dry forests. It is threatened by habitat loss. Its native names are reungkah in Acehnese and kedih in Alas. It can be found in Gunung Leuser National Park, where substantial populations exist in Ketambe and Bukit Lawang.

Although primarily folivorous, Thomas's langur also eats fruit, flowers, and occasionally toadstools and snails. Like other members of the genus Presbytis, this species has evolved to digest cellulose, and microbes in the gut extract nutrients from leaves. Reflected in this diet of leaves is the extent to which they do consume fruit, which is usually unripe and with high pH levels to avoid killing the microbes they need to digest leaves. Thomas's langur also drinks from holes in trees where water collects or from small pools.

The hair on the top of the head rises in a crown, resembling a mohawk; this crown is white... Wikipedia →