Langurs (Leaf Eating Monkeys) of India
Langurs are leaf-eating primates with a unique multi-chambered stomach that enables them to digest tough plant material during their long resting periods, leading to their distinctive large belly. Their high-fiber diet includes leaves, unripe fruits, bark, and blossoms, all slowly processed by their specialized gut flora. One way to determine if their stomach is working is by listening for their burps. Also Read: All about the King Cobra: Habitat, Venom, Hunting, Diet.
Belonging to the family Cercopithecidae, or Old-World monkeys, langurs are part of a vast primate family comprising 159 species and 23 genera distributed across Africa, India, East, and Southeast Asia. This family is divided into two subfamilies: Cercopithecinae, which includes baboons, macaques, mangabeys, and guenons, and Colobinae, which encompasses leaf-eating monkeys like langurs. The Colobinae subfamily is further categorized into two tribes: Colobini, consisting of Colobus monkeys in Africa, and Presbytini, which includes the Asian langurs.
In India, there are 10 different species of langurs, all belonging to two genera: Semnopithecus and Trachypithecus. The Northern Plains Langur is the most common species, while the Golden Langur and Phayre’s Leaf Monkeys are the rarest among them. Out of these 10 species, four are endangered, three are near threatened, two are least concern, and one is vulnerable according to the IUCN Red List. Also read: Top 10 Most Elusive Wild Animals Found In India.
Initially, the Gray Langur (Semnopithecus entellus) was considered a single species in the subcontinent. However, subsequent taxonomic and molecular studies have led to its division into six different species.
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Northern Plains Grey Langur (Semnopithecus entellus.)
IUCN Status: Least Concern
Distribution: India & Bangladesh (Introduced)
The Hanuman langur, also known as the gray langur (Semnopithecus entellus), is the most widely distributed langur monkey species in India. These langurs are easily spotted in the forests of central and northern India. The male langurs lead a harem and are highly intolerant of other males, regardless of their age. Additionally, there exists a bachelor group comprising males of varying ages. These bachelors seize opportunities to take over the harem of a dominant male. Upon successfully taking over, they often eliminate the offspring of the previous dominant male, including the male babies. Interestingly, in jungle environments, Hanuman langurs are frequently observed in the company of spotted deer, showcasing a symbiotic relationship between the two species.
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South-Western Langur (Semnopithecus hypoleucos)
IUCN Status: Least Concern
Distribution: India
The South Indian version of the grey langur is characterized by the distinct trait of having tails bent backward, unlike the north Indian species where the tails are bent forward. This South Indian variety is further divided into three subspecies: the southern plains langur, Konkan langur, and Malabar langur. Despite being less studied, their behavior and social organization appear to be similar to that of the northern plains langur. One distinguishing feature of this species, besides their backward-bent tails, is their coat coloration, which appears as brownish-orange in the northern subspecies. Additionally, their forearms are notably darker than those of other langur species.
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Tufted Gray Langur (Semnopithecus priam)
IUCN Status: Near Threatened
Distribution: India & Sri Lanka
A different variety from South India exhibits a tail carriage similar to that of the southwestern langur. The scientific name of this species is derived from the resemblance between the Greek headgear worn by Priam, the king of Troy in Greek epics, and the crest of certain subspecies of the tufted grey langur or southeastern langur. In comparison to the aforementioned two species, this variety has less black on its paws. Its behavior is nearly identical to that of other grey langur species.
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Terai Gray Langur (Semnopithecus hector)
IUCN Status: Near Threatened
Distribution: India, Bhutan & Nepal
This medium-sized langur belongs to a crestless race and has a greyish-brown coloration on its back. Similar to all Himalayan langurs, it possesses a forward-looped tail. It features a distinctive grey moustache against a black face and uniformly pale grey hands. Like other grey langurs, this species exhibits associations with chital in the forest. They warn each other of approaching predators, and the langurs occasionally drop food from trees, which the deer then consume.
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Himalayan or Nepal Gray Langur (Semnopithecus schistaceus)
IUCN Status: Near Threatened
Distribution: India, Bhutan, China, Pakistan & Nepal
The Himalayan langur is a species characterized by its dark, mauvish-brown back and pale paws. It closely resembles the Terai langur in many aspects. However, it can be distinguished by its larger body size; it is heavier than both the Terai and Kashmir langur. These langurs inhabit a variety of environments, including subtropical to temperate broadleaf forests, coniferous forests, montane forests, and scrublands.
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Kashmir or Chamba Gray Langur (Semnopithecus ajax)
IUCN Status: Endangered
Distribution: India
This langur species, found in moist temperate mixed deciduous and coniferous forests, is a large hill langur. It shares similarities with the Himalayan langur, characterized by its blunt head, mane, and mauve-brown back. Like the Himalayan langur, it also has a whitish venter and a forward-looping tail. However, it can be distinguished by its dark hands and forearms.
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Nilgiri Langur (Semnopithecus johnii)
IUCN Status: Vulnerable
Distribution: Western ghats (India)
This species also belongs to the Semnopithecus genus and was identified and classified a long time ago. It is a slender, black monkey native to the rainforests of the Western Ghats. This monkey is distinguished by its yellow-tinted coiffure and long, glossy black coat. Langurs found north of the Palghat gap in the Western Ghats reportedly have more grizzled white hair on their hindquarters compared to those located south of it. Female individuals of this species feature a white patch on the inside of their thighs. When born, they are pinkish-white with reddish hair that gradually turns black within two to three months.
Endemic to India, these monkeys are highly vocal. Their characteristic ‘hoo-hoo’ calls can be predominantly heard at dawn and sometimes at dusk, making them the most vocal among southern forest monkeys.
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Golden Langur (Trachypithecus geei)
IUCN Status: Endangered
Distribution: Assam (India) & Bhutan
The golden langur, considered one of the most beautiful Indian langurs, exhibits deep cream to off-white fur during the non-breeding season (from April to September) and transitions to a striking golden-orange hue during the breeding season (from October to March). This langur is distinguished by its long, tasselled tail. Female golden langurs have a more pronounced golden coloration and display additional orange on their hindquarters. In their infancy, these langurs are orange-brown with pink faces, palms, and soles, which gradually transform into the adult coloration within three months.
First identified by the renowned naturalist E.P. Gee in 1956, the golden langur has been a symbol of langur conservation efforts in India ever since. These langurs are primarily found in the region between the Manas and Sankosh rivers, spanning across Kokrajhar, Bongaigaon, and Dhubri districts of Assam.
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Phayre’s leaf monkey (Trachypithecus phayrei)
IUCN Status: Endangered
Distribution: Bangladesh, India (Assam, Mizoram, Tripura), Myanmar
Phayre’s leaf monkey, also known as the spectacled monkey, is named for its distinctive white eye patches that contrast sharply with its black face. Adding to its striking appearance is a white lip guard, giving it the look of a cricketer wearing sunscreen while playing in the sun. Its body is slate-grey, darkening towards the limbs, and it has a lighter underside. The tail is longer than its body and lightly tasselled, and both males and females have a peaked crest on their heads. While the sexes are similar, females have yellowish pubic callosities, whereas males have flesh-colored ones. Additionally, males have circular white eye rings, while females have roughly triangular ones.These monkeys are primarily found in mixed moist deciduous and semi-evergreen forests, bamboo patches, and forest fringes, including tea gardens.
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Capped Langur (Trachypithecus pileatus)
IUCN Status: Endangered
Distribution: Bhutan, India (Assam, Arunachal Pradesh),
These monkeys serve as the North-eastern counterparts to the grey langur and are the predominant forest primates in North-east India. They are strictly arboreal, rarely venturing onto the ground. One distinctive feature for identifying this species is the conspicuous cap of differently colored hair. Additionally, they have a greyish dorsal side and a long tail that darkens towards its tip.
In conclusion, langurs, commonly known as leaf-eating monkeys, are a diverse and fascinating group of primates found across India.
India’s langurs play a vital role in the country’s biodiversity, residing in various habitats such as moist deciduous and semi-evergreen forests, bamboo patches, and even human-made environments like tea gardens. Their conservation status, as determined by the IUCN Red List, highlights the need for focused efforts to protect these species, with four of them classified as endangered. Also read: Tiger Safari in India: A Safe and Thrilling Adventure.
Langurs not only serve as biological indicators of the health of their habitats but also enrich the cultural and ecological tapestry of India. As efforts continue to conserve their populations and preserve their habitats, langurs remain an integral part of India’s natural heritage, embodying the country’s rich biodiversity and evolutionary history.
