Black-Crested Sumatran Langur, Presbytis melalophos
BLACK-CRESTED SUMATRAN LANGUR
Presbytis melalophos
Geographic Distribution and Habitat
Also known as the mitered surili or yellow-handed mitered langur, the black-crested Sumatran langur is endemic to (meaning only found in) southwestern Sumatra, south of the Wampu and Simpang Kiri Rivers, and on the island of Pini in the Batu Archipelago off the west coast of Sumatra. They are found in a variety of habitats, from wet rainforests to drier shrubland, on hillsides and in lowlands. Black-crested Sumatran langurs have been found in both primary forests that have not been impacted by human development, as well as secondary forests that have experienced human disturbance, and have even been known to live in rubber plantations. Much of the black-crested Sumatran langur’s habitat is patchy due to deforestation, putting separate groups at risk of isolation.
Langurs in the Presbytis genus have contributed to quite a few disagreements and headaches amongst taxonomists, and continue to do so. This, in part, has to do with the 50 described color variants across the genus, making it difficult to tell where the differences in fur color end in one species and begin in another without genetic insight. At first, Presbytis melalophos included the Raffles’ banded langur and the Bornean banded langur, but eventually researchers elevated the Raffles’ banded langur to species level and, until more recently, considered the Bornean banded langur a subspecies. P. melalophos was then assigned to most surilis across Sumatra with several subspecies. Now, with the help of genetic analysis, all former subspecies of P. melalophos have been elevated to their own species, with only the black-crested Sumatran langur still carrying the scientific name.
Size, Weight, and Lifespan
We don’t have the specific measurements for the black-crested Sumatran langur, but they likely are similar in size to other langurs and would be expected to have a head and body length within roughly 15.75 inches–23.62 inches (40 cm–60 cm), and weigh roughly between 11.02 pounds–17.63 pounds (5 kg–8 kg). Langurs do not tend to be sexually dimorphic, and males and females will typically be about the same size.
Likewise, their lifespan is unknown, but they can likely live up to around 20 years like other langurs.
Appearance
The black-crested Sumatran langur actually comes in a range of colors, leading to some of the confusion with their taxonomy. Their arms, legs, tail, and the top of their head may be anywhere from a light buttery yellow to bronze in color, fading into darker brownish fur on their back. The fur on their bellies and inner thighs is white, spreading up to their necks giving the appearance of a white collar. The fur on the very top of their head comes to a black point, giving them their name. The skin on their faces is also black, contrasted by pale pink eye rings.
Diet
Like all langurs, the black-crested Sumatran langur is primarily folivorous and has developed special adaptations for their leafy diet. These include a multi-chambered “ruminant-like” stomach full of special bacteria that break down cellulose, as well as sharp molars for shredding denser leaves, and large salivary glands that help start breaking down plant material before it even gets to the stomach, thanks to special enzymes in their saliva. While these specializations are particularly useful for feeding on leaves, they also help the langurs eat other things like flowers, fruits, and seeds, adding some variety to their favorite salads.
Behavior and Lifestyle
With the confusion around the taxonomy of the black-crested Sumatran langur, we have now come to realize that much of what we thought we knew about them actually came from studies of different langur species. While we now lack many specifics on what makes the black-crested Sumatran langur’s behavior different from other langurs, we do know how they’re similar. Like other langurs, the black-crested Sumatran langur is arboreal and makes full use of the forest canopy while rarely descending to the ground. Their lanky arms and legs are perfect for swinging, leaping, and running about the branches. They are diurnal and sleep at night in specific sleeping trees to prepare for a long day of foraging (and, likely, napping) ahead.
Black-crested Sumatran langurs are known as Simpai in the native Malay language.
While what we know about the day-in-the-life of a black-crested Sumatran langur is limited, we do know that they love to snack. A black-crested Sumatran langur troop will typically travel 0.19 miles–0.85 miles (300 m-1360 m) daily, either actively foraging in the forest canopy or searching for feeding trees. The troop’s home range will typically be about 3531 acres (1429 ha), and the group consists of about 2–8 individuals with a single adult male and multiple females (plus any infants, juveniles, and subadults). Because males will leave their home group once mature, the social system is mainly female-bonded. Males don’t typically involve themselves in grooming or otherwise socialising with the group, and spend most of their time keeping an eye out for any potential threats.
Few studies have been done on the black-crested Sumatran langur’s ways of communication, but we do know that they are mostly vocal. Vocalizations can be used to warn other langurs of threats, reinforce social bonds, or exert dominance. Males are known to give a series of loud calls during encounters with other groups.
Visual signals may also play an important role in the black-crested Sumatran langur’s communication, conveying threats, affection, dominance, or submission. This may be done through various gestures and facial expressions, similar to how we also communicate, but unfortunately, we don’t have descriptions of what this may look like for the black-crested Sumatran langur.
While we don’t know much specifically about the black-crested Sumatran langur’s reproduction, we do know some things about langurs generally that likely also apply to them. Gestation is likely 6-7 months, after which the mother will give birth to a single infant. The babies (also referred to as neonates) are whitish-gray in color, with a single dark stripe down the back. Researchers think that the striking difference in fur color of langur babies from adults helps the entire troop keep track of the baby since the bright white fur is easier to see. Allomothering (where females besides the mom help take care of an infant—typically the grandmother and/or aunts) is thought to be rare among black-crested Sumatran langurs, but is fairly common for other langur species. Males don’t take much of an active role in parenting, but are defensive of infants from potential threats.
Once mature, males will leave their natal group to find their own group, while females typically stay in their home group. Females are often responsible for initiating sexual interactions among langurs, and researchers think that female choice is important in influencing male dispersal.
While the black-crested Sumatran langur’s ecological role has not yet been specifically studied, we can make some guesses as to what makes them important in maintaining their ecosystem based on what we know about their biology. Because they do eat some fruit and seeds, they likely help the seeds they consume spread and grow into new trees, therefore helping to maintain the biodiversity of the forest.
Some researchers also think that leaf-eating monkeys, such as the black-crested Sumatran langur, may also play a role as “ecosystem engineers” by opening up the forest canopy while consuming leaves and allowing sunlight to enter lower canopy layers.
The black-crested Sumatran langur is classified as Endangered by the International Union for Conservation of Nature (IUCN, 2015), appearing on the IUCN Red List of Threatened Species. Their population levels are decreasing.
The main threat to black-crested Sumatran langurs is habitat loss. Between 2000 and 2012, black-crested Sumatran langurs lost 62% of their habitat. The leading cause is clearing forests for oil palm plantations, which is often done by first burning the forest away. Fires will sometimes get out of hand, especially when conditions are drier during El Niño, which is also exacerbated by climate change. Further, the carbon released by burned trees then enters the Earth’s atmosphere and continues to contribute to climate change. Logging (done both legally and illegally in protected areas) has also been found to be a huge contributor to deforestation throughout Sumatra. Black-crested Sumatran langurs are also targeted by hunters for bushmeat and are sold in the pet trade.
Black-crested Sumatran langurs are listed in Appendix II of the Convention on International Trade in Endangered Species (CITES), an international agreement between governments whose goal is to ensure that international trade in specimens of wild animals and plants does not threaten their survival.
The flexible diet of black-crested Sumatran langurs and their ability to live in secondary forests and even rubber tree plantations is a good sign for how the species will respond to conservation efforts. Because it is important in wildlife conservation to also uplift the local people who live with the wildlife, experts highlight the need for “wildlife-friendly” farming practices. For example, rubber trees have the potential to be grown in more of a forest setting (also referred to as “jungle rubber”) rather than the typical monocultures that are devoid of diversity, thus allowing farmers to continue their harvest without destroying habitat.
The Round Table of Sustainable Palm Oil (RSPO) has provided a set of criteria to ensure the sustainable production of palm oil, largely by maintaining existing plantations to reduce further destruction of forests. While palm oil plantations have less potential to be grown in the biodiverse setting that rubber trees can, they are an important crop for many farmers, and trying to replace them may lead to further deforestation. To help consumers make wildlife-friendly shopping decisions, the World Association of Zoos and Aquariums (WAZA) created the PalmOil Scan app to easily check the sustainability of their purchases.
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- https://www.waza.org/news/waza-palm-oil-scan-app/
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- Citation: [Douglas Brandon-Jones, Vincent Nijman].[Presbytis, melalophos, ]. © All the World’s Primates. N Rowe, M Myers, eds. (alltheworldsprimates.org) Downloaded 8/22/2025
Written by Lina Rademacher, Aug 2025