Thomas’s Langur (Presbytis thomasi) lives in tropical rainforest across Northern Sumatra Indonesia. It feeds on leaves and fruits. Its conservation status is Vulnerable.
Fascinating facts about the Thomas’s Langur
- Thomas's langur occurs only in northern Sumatra, Indonesia, making it a regional endemic. It does not live south or east of Lake Toba and the Alas and Wampu rivers, so its range is confined to the area north of those landmarks. The species is known from Gunung Leuser National Park, where substantial populations exist in Ketambe and Bukit Lawang. This limited distribution ties the monkey closely to the dry forest habitats of the north.
- A crown of hair rises on the top of its head, shaped like a mohawk and coloured white at the front. A dark grey stripe runs down the centre of this crest, giving the monkey a striking head pattern. Two tufts of fur extend on either side of its face, while the belly is cream coloured and the back is grey. Amber eyes framed by grey outlines complete its distinctive facial appearance.
- The langur includes fruit in its diet, but the fruit is usually unripe. Its high pH helps avoid harming the gut microbes that break down the leaves the monkey relies on. In addition to leaves, it also eats flowers, occasionally toadstools and snails, and drinks water collected in holes in trees or small pools. This varied intake supports its specialised cellulose-digesting gut microbes.
- In its natural environment a Thomas's langur can expect to survive about twenty years, a lifespan that reflects the pressures of predation and habitat change. When humans keep the primate in captivity, individuals have been recorded living up to twenty nine years, a notable increase over wild expectations.
- Sunda clouded leopards, Sumatran tigers, Asian golden cats and reticulated pythons all hunt Thomas's langur, and these predators become especially lethal when the monkey is on the ground. The species therefore faces a heightened risk whenever it descends from the canopy to forage or drink. In addition to predation, the langur is also threatened by habitat loss, which reduces the safe arboreal space it relies on for escape and feeding.
Sources
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At a glance
RangeNorthern Sumatra Indonesia
HabitatTropical rainforest
DietLeaves and fruits
About the Thomas’s Langur
In the lush, emerald canopies of Sumatra's forests, the Thomas's Langur reigns as a agile and enigmatic prince, its tawny coat glistening like burnished gold as it leaps with effortless ease from branch to branch. With each bounds, its long, slender tail streams behind, a counterbalance to the langur's daring acrobatics, as it navigates the intricate network of its arboreal realm with the precision of a seasoned aerialist. As it moves, the langur's large, dark eyes seem to hold a deep intelligence, a quiet awareness of its place within the delicate balance of its ecosystem.
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Thomas’s Langur photographed on Feravox
