Langurs, part of the Colobinae subfamily, represent Old World monkeys recognized for their elongated bodies, extended tails, and remarkable facial features. They are primarily tree-dwelling, spending most of their lives amid the canopy of diverse forest environments. Langurs are notable for their intricate social structures, unique means of communication, and crucial ecological roles, especially in seed dispersion and forest rejuvenation.
Numerous langur species exist, each boasting distinct traits and behaviors. However, a common characteristic they share is an herbivorous diet (folivorous) consisting mainly of leaves, fruits, and blossoms. This preference in food consumption significantly shapes their habitat, affecting plant communities and the overall structure of the forest.
Primarily, all langur species are grouped under the tribe Presbytini with 3 genera, namely Trachypithecus (Lutungs), Presbytis (Surilis), and Semnopithecus (Gray Langurs). Langurs inhabit an extensive geographic range, mainly in Asia.
Their habitats stretch from Southeast Asia’s lush rainforests to the Himalayas’ lofty altitudes. Some species have also adapted to landscapes dominated by humans, living near urban zones and places of religious significance.
Despite their adaptability and ecological importance, langurs face multiple threats. The loss of habitat, hunting, and conflicts with humans have decreased populations in many regions. Therefore, efforts for conservation are vital to ensure the survival of these intriguing creatures.
On this page, we dive into the world of langurs, exploring their physical attributes, their classifications, eating habits, different types of langurs, and the challenges they encounter today. By understanding these facets, we can more fully appreciate their role in our ecosystems and the pressing need for their preservation.
Langur Physical Characteristics
- Langurs are primates of medium to large size, sporting body lengths that span from 40 to 80 centimeters, not including their tails, which can stretch to an impressive 1 meter. They are characterized by a slender physique, long limbs, and a tail that assists in maintaining balance. These physical features make them skilled climbers and leapers – a vital adaptation for their tree-dwelling way of life.
- The fur coloration of langurs varies greatly among different species, spanning shades from silvery grey and golden to black and brown. Some species, like the Silvered Langur, are recognized for their eye-catching silvery-grey coat, while others, such as the Golden Langur, are notable for their bright golden fur. Certain species also have distinctive facial markings. For example, the Black-faced Langur presents a striking contrast between its black face and light-colored body.
- Langurs possess several adaptations to excel in tree canopies. Their elongated, robust tails offer balance and stability when navigating the branches. Their hands and feet are built for gripping, with opposable thumbs that enable them to hold onto branches securely. They also have a specialized stomach, akin to a cow, facilitating the efficient digestion of leaves and other tough plant materials.
- Unlike other Old-world monkeys, langurs do not have cheek pouches.
- The average lifespan of langurs is about 20 years, and the gestation period is about 6 to 7 months for langurs.
- Generally, male langurs are larger and weightier than their female counterparts, a phenomenon known as sexual dimorphism. They also sport more pronounced canine teeth, which come in handy during fights for dominance within the troop. In certain species, males also have distinctive fur colorations or markings that differentiate them from females.
Langur Feeding Habits and Diet
Langurs are primarily herbivores, with a diet that consists largely of leaves, fruits, flowers, and occasionally, insects and tree bark. Their food preferences and foraging behavior are closely tied to their environment and the availability of food sources.
- Leaves, particularly young leaves, form the staple of a langur’s diet due to their availability throughout the year. However, langurs consume many fruits and flowers, especially during their seasons. This varied diet provides essential nutrients and plays a crucial role in seed dispersal, contributing to the biodiversity and health of their habitats.
- Langurs exhibit a unique foraging behavior known as ‘browse line‘, where they feed on leaves and fruits at a particular height on a tree before moving to another. This behavior is thought to minimize competition for food resources within the troop and promote efficient foraging.
- The impact of langurs’ feeding habits extends beyond their immediate survival needs. By feeding on various plant species, they help control the growth of certain plants, thereby influencing the composition and structure of plant communities. Their role as seed dispersers also aids in the propagation of many tree species, contributing to forest regeneration and diversity.
- Interestingly, langurs have a specialized digestive system, similar to ruminants, that allows them to break down leaf cellulose. This multi-chambered stomach hosts a community of microorganisms that ferment the plant material, enabling the extraction of nutrients that would otherwise be inaccessible.
- Despite their adaptability, changes in food availability due to habitat loss and human encroachment pose significant challenges to langurs. These changes can impact their feeding habits, nutritional intake, and ultimately, their survival and reproductive success. As such, understanding and preserving the natural habitats of langurs is crucial for their continued survival.
- Anatomically, their digestion system is more sophisticated to digest complex wild leaves using a foregut fermentation process that detoxifies the complex plant compounds by bacteria before entering into the intestine. A similar digestion system can be witnessed in other herbivores such as deer, antelopes, and sloths.
Types of Langurs
Note: Although some odd-nosed monkeys are called langurs, such as Doucs langurs (Pygathrix) or Pig-tailed langurs (Simias), they are also listed under langurs here.
Annamese Silvered Langur
Species Name: Trachypithecus margarita
The Annamese langur is another Old-World monkey in the subfamily Colobinae. Annamese langurs are covered in thick, gray fur. They have dark faces, and the space around the eyes is pale and forms a ring, often in the flesh. Trachypithecus margarita is a monotypic species as it has no subspecies.
Banded Langur
Species Name: Presbytis femoralis
The Banded langur, also known as the Raffles' banded langur or banded leaf monkey, is a primate species in the Cercopithecidae family. Like other Colobin monkeys, whose young typically have lighter-colored fur than adults, Banded langur infants have white or tan fur until it darkens around 6 months.
Bengal Sacred Langur
Species Name: Semnopithecus entellus
The Bengal sacred langur, also known as Hanuman's langur and the northern plains gray langur, is a primate species in the Cercopithecidae family. The Bengal sacred langurs are often referred to as "Hanuman's langurs", named after Lord Hanuman - the Hindu god.
Black and White Langur
Species Name: Presbytis bicolor
The black-and-white langur is a primate species in the Cercopithecidae family. It was formerly thought to be a subspecies of the Presbytis melalophos (black-crested Sumatran langur). Still, the genetic analysis indicated they were separate species.
Black Sumatran Langur
Species Name: Presbytis sumatrana
The black Sumatran langur is a species of monkey in the Cercopithecidae family that is endemic to Indonesia's Sumatra Island. Presbytis sumatrana was once considered a subspecies of Sumatran Surili. Still, genetic analysis has shown it to be a distinct species.
Black-Crested Sumatran Langur
Species Name: Presbytis melalophos
The black-crested Sumatran langur (Presbytis melalophos), also called the Mitred leaf monkey, is a primate species in the Cercopithecidae family. The black-crested Sumatran langur, Raffles' banded langur, Sarawak surili, and black-and-white langur were formerly considered subspecies of Presbytis melalophos.
Black-footed Gray Langur
Species Name: Semnopithecus hypoleucos
The black-footed gray langur is an Old-World monkey, one of the langur species. Like other gray langurs, this species is a leaf-eating monkey in southern India. The black-footed gray langur is distributed throughout southwestern India (Kerala, Karnataka, and Goa) but is concentrated in the Western Ghats.
Black-shanked Douc Langur
Species Name: Pygathrix nigripes
One of three species of Douc langur (the gray-footed and the red-footed are the other two), the black-shanked douc langur is only found in southwestern Vietnam and eastern Cambodia, inhabiting primary monsoon forests as well as secondary and tropical forests.
Capped Langur
Species Name: Trachypithecus pileatus
The capped langur is a type of monkey in the Cercopithecidae family. These langurs can vary in appearance. This Asian primate gets its name from the thick hairs on the top of the head, typically gray or black.
Cat Ba Langur
Species Name: Trachypithecus poliocephalus
The white-headed langur, also called the Cat Ba langur, is an endangered species of langur native to Guangxi, China. Cat Ba langurs are comfortable in trees or ground but prefer steep cliffs where humans can't set foot.
Cross Marked Langur
Species Name: Presbytis chrysomelas
The Sarawak surili, also known as Cross-marked Langur, is a monkey species in the Cercopithecidae family. The Sarawak surili was once considered widespread but has declined significantly due to habitat and loss persecution.
Delacour’s Langur
Species Name: Trachypithecus delacouri
The Delacour's langur, also known as Delacour's Lutung, is an endangered Lutung native to northern Vietnam. The species is named after Jean Théodore Delacour, a French-American ornithologist.
Dusky Langur
Species Name: Trachypithecus obscurus
Dusky langurs also known as spectacled langurs, spectacled leaf monkeys, and dusky leaf monkeys, are primarily found in the Malay Peninsula in Asia. White rings surrounding the deep, dark eyes give the species its alternative name, the spectacled monkey or spectacled langur, for a "bespectacled" look.
East Javan Langur
Species Name: Trachypithecus auratus
The East Javan langur, also called the Javan lutung, Javan langur, or ebony langur is an Old-World primate in the subfamily Colobinae. As with all langurs, the East Javan langur is a social animal, living in groups of about 7 individuals, with 1 or 2 adult males in the group.
East Sumatran Banded Langur
Species Name: Presbytis percura
The East Sumatran banded langur also called the East Sumatran banded surili are primarily found in the fragmented landscape of pulp and rubber plantations. These surilis are shy and alert creatures, rarely leaving the comfort of their canopies.
François’ Langur
Species Name: Trachypithecus francoisi
The François langur, also called the white side-burned black langur, François leaf monkey, or Tonkin leaf monkey is a species of Lutung and the type species of its species group. The François langur is among the least studied langur species.
Gee’s Golden Langur
Species Name: Trachypithecus geei
Gee's golden langur, also known simply as the golden langur, is an Old-World primate found in a small area of western Assam, India, and in the nearby foothills of the Black Mountains of Bhutan. Gee's golden langur was officially discovered in 1953 by Edward Pritchard Gee, an amateur naturalist and tea planter in Assam, India.
Germain’s Langur
Species Name: Trachypithecus germaini
Germain's Langur is a lutung species endemic to Thailand, Vietnam, Laos, Cambodia, and Burma. Germain's langur is a terrestrial tree-dwelling species occasionally found in lowlands.
Gray-Shanked Douc Langur
Species Name: Pygathrix cinerea
The gray-shanked douc langur (Pygathrix cinerea) is a species of douc endemic to the Vietnamese provinces of Gia Lai, Quảng Ngãi, Kon Tum, Bình Định, and Quảng Nam. Genetically, Gray-shanked douc langurs are similar to Red-shanked douc langurs (Pygathrix nemaeus).
Hatinh Langur
Species Name: Trachypithecus hatinhensis
The Hatinh langur (Trachypithecus hatinhensis) is a critically endangered Old World monkey found in the limestone forests of Vietnam, particularly in Quảng Bình province. Contrary to their common name, the Hatinh langur is not known from the province of Hà Tĩnh.
Hose’s Langur
Species Name: Presbytis hosei
The Hose's langur (Presbytis hosei) is a primate species in the Cercopithecidae family native to the island of Borneo, which includes Brunei, Kalimantan (Indonesia), and eastern Malaysia. The species was first identified in 1985 in Sangkulirang Peninsula and Kutai National Park in East Kalimantan, Indonesia.
Indochinese Black Langur
Species Name: Trachypithecus ebenus
The Indochinese black langur (Trachypithecus selbstus) is a little-known Lutung endemic to Laos and neighboring Vietnam. Because they live in dense forests and rarely venture outside, observing them in the wild can be difficult.
Indochinese Grey Langur
Species Name: Trachypithecus crepusculus
The Indochinese gray langur (Trachypithecus crepusculus) is a species of Lutung native to Southeast and East Asia. This species was once thought to be conspecific with the Phayre's leaf monkey (Trachypithecus phayrei).
Javan Surili
Species Name: Presbytis comata
The grizzled surili (Presbytis comata) is a threatened species of Old World monkey native to the western half of Java, Indonesia, a biodiversity hotspot. The grizzled surili engages in 3 to 4 foraging and feeding fights throughout the day.
Kashmir Gray Langur
Species Name: Semnopithecus ajax
The Kashmir gray langur is an Old-World monkey, one of the species of langurs. The Kashmiri gray langur derives its scientific name, Semnopithecus ajax, from a character in the ancient Greek poem - The Iliad - set during the Trojan War.
Laotian Langur
Species Name: Trachypithecus laotum
The Laotian langur (Trachypithecus laotum), also known as white-browed black langur, is another primate species that nest in small limestone caves and holes that shelter from predators, rain, and cold.
Maroon Langur
Species Name: Presbytis rubicunda
Endemic to the jungles of Borneo in Indonesia and Malaysia, red leaf monkeys get their name from their shaggy reddish-maroon fur. They are also known as maroon-leaf monkeys and maroon langurs.
Mentawai Langur
Species Name: Presbytis potenziani
Mentawai Langur is also called the Long-Tailed Langur, and it is native to the Mentawai Islands in Indonesia. The pelage of Mentawai langur is medium length, longer on the back of the shoulders and anterior of the flanks and shorter on the face, neck, abdomen, and under the thighs.
Miller’s Langur
Species Name: Presbytis canicrus
Miller's Langur (Presbytis canicrus), also called the Kutai Gray Langur, is the rarest of the four Hosei subspecies, all of which are native to the island of Borneo. One of the world's most endangered primates, Miller's langur, was once considered extinct until it was rediscovered in 2013.
Mitered Langur
Species Name: Presbytis mitrata
The mitered langur has brown or gray fur on its back, darker, while it is even darker on its belly and the arms, legs, and tail. These Indonesian primates live in groups of 1 male with 5 to 17 females.
Nepal Gray Langur
The Nepal gray langur (Semnopithecus schistaceus) is a gray langur native to the Himalayas of Nepal, extreme southwestern Tibet, northern Pakistan, northern India, Bhutan, and possibly Afghanistan. The Nepal gray langur is both terrestrial and arboreal.
Nilgiri Langur
Species Name: Semnopithecus johnii
The Nilgiri langur (Semnopithecus johnii), also called the black-leaf monkey, John's langur, and Indian hooded leaf monkey is a langur (a species of Old-World monkey) found in the Nilgiri foothills of the Western Ghats in southern India.
North Sumatran Leaf Monkey
Species Name: Presbytis thomasi
The North Sumatran leaf monkey (Presbytis thomasi), also called Thomas's langur, is a primate species in the Cercopithecidae family. The North Sumatran leaf monkeys spend most of the day in groups resting, moving, or feeding.
Pale-Thighed Langur
Species Name: Presbytis siamensis
The pale-thighed surili (Presbytis siamensis), also called the white-thighed langur, is a primate species in the Old World monkey family (Cercopithecidae). Pale-thighed langurs are savvy herbivores; it's fun to say they only eat plants and have a fussy palate, with a preference for young leaves, seeds, and fruits.
Phayre’s Langur
Species Name: Trachypithecus phayrei
Phayre's leaf monkey (Trachypithecus phayrei), also called the Phayre's langur, is a species of Lutung endemic to South and Southeast Asia. The name commemorates the late Sir Arthur Purves Phayre, a lieutenant general in the British Indian Army and commissioner of the entire province of former British Burma.
Pig-tailed Langur
Species Name: Simias concolor
The pig-tailed langur (Simias concolor), monotypic in the Simias genus, is a great Old-World monkey native to several small islands off Sumatra, Indonesia. Adult pig-tailed langurs have black faces and small, turned-up noses.
Popa Langur
Species Name: Trachypithecus popa
Popa langur (Trachypithecus popa) is a primate species in the Cercopithecidae family. It occurs exclusively in Myanmar. The species is named after Mount Popa, where a population of 100 monkeys lives.
Proboscis Monkey
Species Name: Nasalis larvatus
The proboscis monkey (Nasalis larvatus) is an Old World arboreal species with an unusually large nose, reddish-brown skin color, and a long tail. The proboscis monkey is a large species and one of the largest old-world monkey species native to Asia.
Purple-faced Langur
Species Name: Semnopithecus vetulus
The purple-faced langur (Semnopithecus vetulus), also called the purple-faced leaf monkey, is an Old World species native to Sri Lanka. The purple-faced langur is found in the closed forests of Sri Lanka's mountains and in the southwestern part of the country known as the 'wetland'.
Red-Shanked Douc Langur
Species Name: Pygathrix nemaeus
The red-shanked douc langur is an Old-World monkey species that is one of the most colorful primates. Red-shanked douc langurs are genetically similar to gray-shanked douc langurs; however, they are considered a different species due to their different biological characteristics.
Robinson’s Banded Langur
Species Name: Presbytis robinsoni
Robinson's banded langur (Presbytis robinsoni), also known as Robinson's banded surili, is a monkey species in the Cercopithecidae family. Robinson Banded Langurs are generally shy and alert creatures, rarely leaving the comfort of the canopy.
Saban Grizzled Langur
Species Name: Presbytis sabana
Saban Grizzled Langur was once thought to be a subspecies of the Hose's langur, Presbytis hosei (as Presbytis hosei sabana). The Saban grizzled langur is endemic to the island of Borneo in the Malaysian province of Sabah, with part of its range in Indonesia.
Selangor Silvered Langur
Species Name: Trachypithecus selangorensis
The Selangor silvered langur (Trachypithecus selangorensis) is a leaf monkey living on the west coast of the Malay Peninsula. Like most leaf monkeys, the Selangor silvered langur usually lives in groups of a single adult male and several adult females and their young offspring.
Shan State Langur
Species Name: Trachypithecus melamerus
Shan State Langur was generally considered a subspecies or a synonym of Phayre's leaf monkey (Trachypithecus phayrei) until Roos et al. elevated it to species status in 2020.
Shortridge’s Capped Langur
Species Name: Trachypithecus shortridgei
The Shortridge's capped langur (Trachypithecus shortridgei) is a colobine primate inhabiting low to medium evergreen and semi-evergreen forests east of the Chindwin River in northeastern Myanmar and southwestern Myanmar, China, in the Nu and Dulong valleys.
Siberut Langur
Species Name: Presbytis siberu
Siberut langurs are native to the islands of North Pagai, South Pagai, and Sipora. Siberut langurs spend over 80 percent of their time resting and foraging and only a tiny portion traveling and socializing.
Silvered Langur
Species Name: Trachypithecus cristatus
The silvery Lutung (Trachypithecus cristatus), also called the silvery langur or silvered leaf monkey is an Old-World monkey. Silvery Lutungs primarily live in trees.
Tarai Gray Langur
Species Name: Semnopithecus hector
The Tarai gray langur (Semnopithecus hector) is an Old-World monkey and was once thought to be a subspecies of the northern plains gray langur. The Latin name for Tarai gray langurs is inspired by Hector, the prince of Troy.
Tenasserim Langur
Species Name: Trachypithecus barbei
Tenasserim lutung (Trachypithecus barbei) is a species of lutung. It occurs in Thailand and Myanmar. The species derived its common name from the Tenasserim Hills.
Tufted Gray Langur
Species Name: Semnopithecus priam
The tufted gray langur (Semnopithecus priam), also called the Coromandel sacred langur and the Madras gray langur, is an Old-World monkey, one of the langur species. These langurs are generally shy and only descend when there is no visible danger.
West Javan Langur
Species Name: Trachypithecus mauritius
The West Javan langur (Trachypithecus mauritius) is an Old-World monkey of the Colobinae subfamily. It was previously considered a subspecies of Trachypithecus auratus until Roos and Groves raised it to its own species.
White-fronted Langur
Species Name: Presbytis frontata
The white-fronted surili (Presbytis frontata) is a primate species in the Cercopithecidae family, the Old World monkeys. This species prefers to eat immature leaves than more mature leaves.
White-headed Langur
Species Name: Trachypithecus leucocephalus
The white-headed langur (Trachypithecus leucocephalus) is an endangered species of langur native to Guangxi, China. As the common name suggests, a tuft of white fur covers this primate's head.
Langur Conservation Status and Threats
Langurs, like many wildlife species, face a range of threats that have led to declining populations and, in some cases, pushed them toward the brink of extinction. The conservation status of langurs varies among species, with some listed as ‘Least Concern’ while others are classified as ‘Endangered’ or ‘Critically Endangered’ on the International Union for Conservation of Nature (IUCN) Red List.
- Habitat loss is one of the most significant threats to langurs. Rapid deforestation and land conversion for agriculture, infrastructure development, and urbanization have resulted in the fragmentation and loss of their natural habitats. This reduces the availability of food and shelter and increases their vulnerability to predators and human-wildlife conflict.
- Hunting and poaching pose another major threat to langurs. They are hunted for their meat and fur, and in some regions, for traditional medicine. The pet trade has also contributed to the decline in langur populations, with young langurs often being captured and sold as pets.
- Human-wildlife conflict is an increasing concern, particularly for langur species that have adapted to live near human settlements. These conflicts often arise when langurs raid crops or venture into residential areas for food, leading to retaliatory killings.
- Despite these challenges, various conservation efforts and initiatives are underway to protect and conserve langur populations. These include habitat protection and restoration, anti-poaching measures, and community-based conservation programs. Additionally, several captive breeding programs and reintroduction initiatives have successfully bolstered populations of critically endangered langur species.
However, the long-term survival of langurs hinges on integrating conservation efforts with sustainable development practices. It is crucial to balance the needs of human communities with the preservation of natural habitats to ensure a future where both people and langurs can thrive.
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BioExplorer.net. (2024, April 19). Langurs. Bio Explorer. https://www.bioexplorer.net/animals/mammals/monkeys/langurs/.
BioExplorer.net. "Langurs" Bio Explorer, 19 April 2024, https://www.bioexplorer.net/animals/mammals/monkeys/langurs/.
BioExplorer.net. "Langurs" Bio Explorer, April 19 2024. https://www.bioexplorer.net/animals/mammals/monkeys/langurs/.
