On today’s show we learn about the Raffles’ Banded Langur, a critically endangered mammal, a primate, native to southeast Asia, to Singapore and southern Malaysia. Its scientific name is Presbytis femoralis and it was first described in 1838.
For more information about Raffles’ Banded Langur conservation please see Mandai Nature at https://www.mandainature.org/.
Rough Transcript
Intro 00:05
Welcome to Bad at Goodbyes.
On today’s show we consider the Raffles’ Banded Langur.
Species Information 02:05
The Raffles’ Banded Langur is a critically endangered mammal, a primate, native to southeast Asia; to Singapore and southern Malaysia. Its scientific name is Presbytis femoralis and it was first described in 1838.
Description
The Raffles’ Banded Langur is a small to medium sized Old World monkey whose body is roughly 2 feet long with an additional 2.5 foot long tail; so roughly 4-5 feet crown to tail tip with their tail often longer than their body itself. They have 4 long, slender limbs, their hindlimbs (their legs) a bit longer and more muscular than their forelimbs (their arms). They are pentadactyl, so five digits on each limb: four fingers and a pollex (that’s the thumb) on each forelimb, and four toes and a hallux (that’s the big toe) on each hindlimb. Their pollex and hallux, their thumbs and big toes are relatively shortened and their other digits are longer and slightly curved, in a kind-of hook-like grasp.
The Raffles’ Banded Langur is arboreal, tree-dwellers, spending nearly all of their lives high in the forest canopy, dozens and dozens of feet above the ground, rarely venturing down to the forest floor. Their limbs, digits and long tail are adaptations for traversing this tree-top habitat. They move, quadrupedally, using all four of their limbs, hands and feet both, running across branches, grasping trunks, quickly navigating the foliage with great agility. Their strong hindlimbs are used for airborne jumps from tree-to-tree, their forelimbs for catching and gripping the branches on the other side. Their tail aids in balance, serving as a counterweight, actively swinging and rotating to adjust their center of gravity, helping to course correct while scurrying or leaping and to help slow and stabilize once landed.
The Raffles’ Banded Langur has dark brown to black fur on its head, back, limbs, and tail. But with a vertical band of white or grayish fur on the chest, belly, and inner thighs; this stripe lends the Banded Langur its name. Their fur is long-ish and frizzy, covering their entire body but their hands, feet, and face.
Most of the bare skin on their face is a deep grey or black, but with rings of white around their dark eyes and patches of pale-pink or white-ish skin around their nose, mouth, and chin. There is great variation in banded langur facial colorations, so much so that researchers can recognize specific individuals at a distance in the wild on sight.
They have relatively large eyes. Their nose is wide and flat, with narrow vertical nostrils, and they have a thin, wide, very expressive mouth.
Our evolutionary branches forked roughly 25 million years ago but the Langur look… familiar, in their faces and expressions; like it is not hard to see our ancient kinship.
Behavior
Raffles’ Banded Langur are a highly social and generally cooperative species. They organize into troops of 5-10 individuals, a single reproductive adult male, several reproductive adult females, and their offspring. Conflict within a troop is rare. The dominant male is a protective guardian, but will also gently play with growing juveniles. Adult females will alloparent, meaning they will take care of one another’s offspring. And there is minimal internal resource or mating competition.
Social cohesion is maintained through an elaborate communication system of visual signals, touch, and vocalization. Visual communication involves small facial expressions, blinking/staring and gaze aversion, and also full-body physical displays, like branch shaking and vigorous jumping to warn off an encroaching troop.
Tactile communication centers on social grooming. The troop gathers on broad branches to groom one another’s fur, picking coats free of parasites and dirt. So serving a hygienic need but also using closeness and touch to strengthen bonds across the group. Researchers have even observed Raffles’ Banded Langurs engaging in mutual grooming with long-tailed macaques, creating peaceful bonds across primate species.
Raffles’ Banded Langurs also vocalize. A troop’s male will produce a rapid “kuh-kuh-kuh” to declare his troop’s presence and warn others off. Alarm calls are a series of sharp barks. And quiet close communication are soft grunts. We have a recording of Raffles’ Banded Langurs vocalizing from Ding Li Yong, recorded in 2015 in Malaysia. Let’s listen:
[sound recording]
The Raffles’ Banded Langur is diurnal, active during the day and resting at night. A typical day is spent traveling together across the tree-tops to canopy and mid-canopy forage sites, feeding, then digesting and napping and grooming together, across the hottest parts of the afternoon, and then foraging again before sunset. As night falls, the troop returns to their shared sleeping perches, a hundred feet above the forest floor, to rest.
Diet
The Raffles’ Banded Langur is folivorous and frugivorous, they eat leaves and fruit. Fecal studies and observation show they’ll consume a large variety of plant species, but selectively targeting specific parts of specific plants, eating only new growth leaves from one tree while seeking out the ripe fruits and seeds of another; feeding on Rubber Tree, Rambutan, Jackfruit, Malayan Banyan, Durian, Mango, Langsat and dozens more.
They have sharp molars to slice and grind tough plant matter, and have a multi-chambered stomach to break down fibrous vegetation. Their gut microbiome ferments plant material, neutralizing harmful toxins and breaking down complex carbohydrates to extract nutrients.
Reproduction
The Raffles’ Banded Langur is polygynous, one male mates with multiple females within the troop. Pregnancy lasts roughly five to six months before the mother births a single infant. Young are born altricial, helpless, totally dependent for food, warmth, and protection. The mother carries the infant clung to her belly and breast, and provides milk for 12 to 18 months. Other females in the troop, both juveniles and adults, will contribute to caregiving: carrying, minding, and grooming one another’s young while a mother feeds. New langurs begin to learn to climb and traverse for themselves at six to eight months of age. But remain within the communal care of their troop until they reach reproductive maturity at roughly 4-5 years old and set off: males to establish their own troops, females to join another.
Raffles’ Banded Langur live to about 20 years old.
In The Dream
————
In the dream,
Less cars, more trees
More green, less grey
More breath, less smoke
Less death, more life
More quiet, less of the everpresent grind of rubber on concrete
Less individualist, more generous
Less hardened, more soft
More leaves who drink sunlight, less metal that drinks fossils
Less litter, more flowers
More birdsong, less car horn,
More branches for swinging, less highways for fleeing
Less cars, more trees
A tree is a long promise
And I am a simple monkey
Less cars, more trees
In the dream.
————
Habitat
The Raffles’ Banded Langur is native to a small geographic range in Southeast Asia, to the southern states of Pahang and Johor in Malaysia, and to the small island nation of Singapore, between the Indian Ocean and the South China Sea. About two-thirds of the remaining population are scattered in a dozen forest fragments across the southern tip of the Malay Peninsula. The other third of the population is found just over the narrow Straits of Johor in Singapore, mostly in the Central Catchment Nature Reserve.
These are tropical moist broadleaf forest biomes: rainforests and freshwater swamp-forest ecosystems, dense with vegetation and biodiversity. Tall dipterocarp trees, with massive trunks reach 200 feet into the air to form the crest of the forest. Then below at around 100 feet up, is an interlocking canopy of woody lianas, rattan palms, and climbing ferns. Then below a deeply shaded understory of saplings, wild ginger, and fan palms. The forest floor is a thin, decaying mat of leaf litter, surface roots, and damp clays.
The Raffles’ Banded Langur stay primarily within the middle-to-upper parts of the canopy, roughly 80 feet above the forest floor, for forage and travel. When targeting fruit they may climb as low as 30 feet, but rarely lower. They avoid the understory, and do not forage at ground level. They descend to the forest floor only to cross paved roads, or traverse gaps in the canopy where the forest has been fragmented.
The terrain itself is flat; these are lowland plains, cut by some shallow ravines, creekbeds, and swamplands, all less than 700 feet above sea-level.
The climate here is tropical, equatorial, with temperatures relatively steady year-round and the seasons marked instead by monsoon patterns: from November to March: the wet Northeast Monsoon; from June to September: the slightly drier Southwest Monsoon, and with brief transitional inter-monsoon months inbetween.
Throughout the year high temperatures average in the low 90s°F, with lows in the mid 70s. Rain comes in short, intense daily afternoon thunderstorms, and in multi-day downpours during the monsoon seasons. Precipitation averages roughly 120 inches per year.
The Raffles’ Banded Langur shares its tropical forest with:
Flat-leaved Vanilla, Red-breasted Parakeet, Mangrove Marshal, Singapore Predatory Bush-Cricket, Foxtail Palm, Big-leaf Mahogany, Rainbow Gum, Black-backed Dwarf Kingfisher, Spotted Wood-Owl, Malesian Frog, Bombay Rosewood, Southeast Asian Softshell Turtle, Mangrove Pitta, Spotted Black Crow Butterfly, Manila Palm, Smooth-coated Otter, Javan Myna, Reticulated Swamp Crab, Jambu Fruit Dove, Red-crowned Barbet, Burmese-Rosewood, Singapore Shadowdamsel, Red-tailed Sprite, Long-tailed Macaque, Malaysian Plover, and many, many more.
Threats
Historically, the Raffles’ Banded Langur experienced extensive habitat loss in the 19th and 20th centuries. First to land cleared for plantations and mining, during British colonial rule; and later for expanding urbanization. Less than 1% of the primary forest that once stretched across much of Singapore’s main island remains today.
Additionally in the 1900s, small primates across the region, including our Raffles’ Banded Langur were poached, taken from the wild, to be sold as pets.
Today, habitat destruction and fragmentation continue to be major threats to the species. Urban development and infrastructure expansive in Singapore clears forests and cuts roadways through the Langur’s habitat. In Malaysia, agricultural expansion, specifically for oil palm plantations is reducing and fragmenting the Langur’s forests. This though, is a global issue, for example a third of the palm oil imported by the United States originates in Malaysia.
Forest fragmentation presents an additional threat as Raffles’ Banded Langur automobile casualties have been recorded in both Singapore and Malaysia as Langurs leave the forest canopy to attempt travel between fragmented habitats using roads and are struck by cars.
Human-induced climate change, resulting from persistent over-reliance on fossil fuels, is, using moderate models, projected to increase average temperatures in this region by 4.5°F by the end of this century. This will have a profound effect on the dipterocarp trees of the Langur’s habitat. Dipterocarp respond to low-temperature cues for flowering. Warming temperatures make these thermal triggers less frequent leading to decreased flowering and fruit production. Reducing the availability of a key food source for the Langur, and affecting the general reproduction of these tall canopy trees that the monkey relies on for sleeping perches and forest traversal.
Conservation
Fortunately, the Raffles’ Banded Langur is legally protected internationally, and locally protected in both Malaysia and Singapore.
Most populations of the Langur are found on protected land. In Malaysia at the Endau Rompin National Park, the Gunung Arong Recreational Forest, the Rompin State Park, and the Gunung Belumut Recreational Forest. And in Singapore at the Thomson Nature Park, the Central Catchment Nature Reserve, and recently at the Bukit Timah Nature Reserve.
In 2013, the Singapore government built the Eco-Link@BKE, this is an ecological bridge planted with native vegetation, that connects the forests of the Central Catchment Reserve to Bukit Timah over the Bukit Timah Expressway. And earlier this year an adult male Raffles’ Banded Langur was photographed in the Bukit Timah Reserve, the first evidence of the species there in nearly 40 years, who presumably arrived via the Eco-Link bridge.
In 2016, the Raffles’ Banded Langur Working Group (RBLWG), was formed by Mandai Nature with the Jane Goodall Institute, the Singapore National Parks Board, the National University of Singapore, the Malaysian Nature Society, and others to generate a Species Action Plan and implement conservation measures.
As part of that work a citizen science program was run from 2016 to 2019 during which members of the public helped locate, track, and take field observations of the remaining Langur population.
In 2014, the Malaysian Nature Society constructed an experimental rope bridge within the Panti Forest Reserve to facilitate safe crossing of the langurs over Route 3, a major trucking site. In 2019, in Singapore, two similar rope bridges were installed by the National Parks Board, over roadways in the Thomson Nature Park, and we have camera trap evidence of Langurs, Macaques, and Plantain Squirrels using the ropes to safely cross over the roads, bridging fragmented forest patches. And recently the Thomson Nature Park is piloting a trial using roadside cameras and video analysis to provide motorists with rapid real-time alerts when wildlife is crossing roadways.
Nevertheless the Raffles’ Banded Langur has been considered critically endangered on the IUCN Red List since 2022 and their population is in decline.
Our most recent counts estimate that less than 370 Raffles’ Banded Langur remain in the wild.
Citations 31:03
Information for today’s show about the Raffles’ Banded Langur was compiled from:
Ang, A., Boonratana, R. & Nijman, V. 2022. Presbytis femoralis. The IUCN Red List of Threatened Species 2022: e.T39801A215090780. – https://dx.doi.org/10.2305/IUCN.UK.2022-1.RLTS.T39801A215090780.en
Ang, A., D’Rozario, V., Jayasri, S. L., Lees, C. M., Li, T. J., & Luz, S. (2016). Species action plan for the conservation of Raffles’ banded langur (Presbytis femoralis femoralis) in Malaysia and Singapore. IUCN SSC Conservation Breeding Specialist Group. – https://portals.iucn.org/library/node/47506
Ang, A., Jabbar, S., D’Rozario, V., & Lakshminarayanan, J. (2021). Citizen science program for critically endangered primates: A case study from Singapore. Primate Conservation, 35, 179–188. – http://www.primate-sg.org/storage/pdf/PC35_Ang_et_al_Citizen_science.pdf
Ang, A., Roesma, D. I., Nijman, V., Meier, R., Srivathsan, A., & Rizaldi (2020). Faecal DNA to the rescue: Shotgun sequencing of non-invasive samples reveals two subspecies of Southeast Asian primates to be Critically Endangered species. Scientific Reports, 10(1), 9396. https://doi.org/10.1038/s41598-020-66007-8
Cherian, A. (2023, February). Raffles’ banded langur. New England Primate Conservancy. – https://neprimateconservancy.org/raffles-banded-langur/
Ding Li Yong. (2025). Sound recording. Xeno-Canto. XC961056. – https://www.xeno-canto.org/961056
Er, J. (n.d.). Introducing our elusive wild neighbours. National Parks Board. Retrieved October 3, 2026. – https://www.nparks.gov.sg/publications-resources/articles/introducing-our-elusive-wild-neighbours
Haris, H., Othman, N., Kaviarasu, M., Najmuddin, M. F., Abdullah-Fauzi, N. A. F., Ramli, F. F., Sariyati, N. H., Ilham-Norhakim, M. L., Md-Zain, B. M., & Abdul-Latiff, M. A. B. (2024). Ethnoprimatology reveals new extended distribution of critically endangered banded langur Presbytis femoralis (Martin, 1838) in Pahang, Malaysia: Insights from indigenous traditional knowledge and molecular analysis. American Journal of Primatology, 86, e23631. – https://doi.org/10.1002/ajp.23631
Haris, N. (2021). DNA metabarcoding and phytochemical analysis of plants consumed by banded langur (Presbytis femoralis) in Johor. Master’s thesis, Universiti Tun Hussein Onn Malaysia. UTHM Institutional Repository. – https://eprints.uthm.edu.my/6435/
iNaturalist - Singapore
Lai, D. (2026, August 3). Critically endangered Raffles’ banded langur spotted at Bukit Timah Nature Reserve after 39 years. The Straits Times. – https://www.straitstimes.com/singapore/critically-endangered-raffles-banded-langur-spotted-at-bukit-timah-nature-reserve-after-39-years
Malaysian Palm Oil Council. (2021, September 1). Will Malaysia be able to weather the decline in palm oil exports to the United States? MPOC Market Insight. – https://www.mpoc.org.my/will-malaysia-be-able-to-weather-the-decline-in-palm-oil-exports-to-the-united-states/
Mittermeier, R. A., Reuter, K. E., Rylands, A. B., Jerusalinsky, L., Schwitzer, C., Strier, K. B., Ratsimbazafy, J., & Humle, T. (Eds.). (2022). Primates in peril: The world’s 25 most endangered primates 2022–2023. IUCN SSC Primate Specialist Group, International Primatological Society, & Re:wild. – https://static1.1.sqspcdn.com/static/f/1200343/28551465/1665759930773/Top-25-Primates-2022-2023.pdf
Najmuddin, M. F., Haris, H., Norazlimi, N., Md-Zain, B. M., Abd Rahman, M.-R., Shahrool-Anuar, R., Hassan, A. H., & Abdul-Latiff, M. A. B. (2020). Daily activity budget of banded langur (Presbytis femoralis) in Malaysia. Journal of Sustainability Science and Management, 15(5), 84–97. – https://doi.org/10.46754/jssm.2020.07.009
Numata, S., Yamaguchi, K., Shimizu, M., Sakurai, G., Morimoto, A., Alias, N., Noor Azman, N. Z., Hosaka, T., & Satake, A. (2022). Impacts of climate change on reproductive phenology in tropical rainforests of Southeast Asia. Communications Biology, 5(1), Article 311. – https://doi.org/10.1038/s42003-022-03245-8
Najmuddin, M. F., Haris, H., Norazlimi, N., Ruslin, F., Matsuda, I., Md-Zain, B. M., & Abdul-Latiff, M. A. B. (2021). Dietary habits of free-ranging banded langur (Presbytis femoralis) in a secondary-human modified forest in Johor, Malaysia. Zoological Studies, 60, Article 67. – https://doi.org/10.6620/ZS.2021.60-67
Rizaldi, Ilham, K., Prasetio, I., Lee, Z. H., Jabbar, S., & Ang, A. (2019). Preliminary study on the distribution and conservation status of the East Sumatran banded langur Presbytis femoralis percura in Riau Province, Sumatra, Indonesia. Asian Primates Journal, 8(1), 25–36. – http://static1.1.sqspcdn.com/static/f/1200343/28234574/1577091893337/2019Dec23_Article_3.pdf
Tay, L. S., Choo, R., Khoo, M. D. Y., Kong, E., Chan, Y. X., Neo, W. H. Y., Ow, S., Toh, Y. H., Ling, H., Soh, M. C. K., Lee, B. P. Y.-H., Loo, A. H. B., & Er, K. B. H. (2024). A suite of wildlife crossing structures facilitates mammal movement across tropical forest fragments in a city. Ecosphere, 15(12), Article e70114. https://doi.org/10.1002/ecs2.70114
Woolloff, A., Svensson, M. S., Jabbar, S., Ang, A., & Nijman, V. (2023). Population viability analysis of the population of Raffles’ banded langurs Presbytis femoralis in Singapore. Raffles Bulletin of Zoology, 71, 542–552. – https://doi.org/10.26107/RBZ-2023-0041
Wikipedia – https://en.wikipedia.org/wiki/Raffles%27_banded_langur
For more information about Raffles’ Banded Langur conservation please see Mandai Nature at https://www.mandainature.org/
Music 33:20
Pledge 41:20
I honor the lives of all Raffles’ Banded Langur. I will commit their name to my record. I am grateful to have shared time on our planet with this being. I lament the ways in which I and my species have harmed and diminished this species. I grieve.
And so, in the name of the Raffles’ Banded Langur I pledge to reduce my consumption. And my carbon footprint. And curb my wastefulness. I pledge to acknowledge and attempt to address the costs of my actions and inactions. And I pledge to resist the harm of plant and animal kin and their habitat, by individuals, corporations, and governments.
I forever pledge my song to the witness and memory of all life, to a broad celebration of biodiversity, and to the total liberation of all beings.
