S. entellus was previously known as Presbytis entellus. They received their common name, Hanuman langur, from Hanuman who is the monkey-god.
Hanuman langurs have about 19 different types of calls. In the morning, mature males make a loud whooping call when leaving their sleeping trees. They may also make cacophonous barks if they are surprised by a predator. Adult and sub-adult males often grunt or cough during group movements. Isolation peeps can be heard from members who get lost or separated from their group. They often groom each other, which is performed according to local dominance hierarchies. Dominant Hanuman langurs groom one another and receive grooming more often than subordinate langurs. They use their vision to find food and move around their environment and females display estrous via head shaking.
Communication Channels: visual ; tactile ; acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
Hanuman langurs are listed as a species of "least concern" on the IUCN Red List of Threatened Species. It was previously listed as near threatened in 2004.
US Federal List: no special status
CITES: appendix i
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
Hanuman langurs are known to raid crops and steal food from people’s homes.
Negative Impacts: crop pest
Hanuman langurs are sacred animals in many parts of India. Various body parts are sometimes kept as amulets, which are thought to have a positive effect on the bearer (Gron, 2008).
Positive Impacts: pet trade ; body parts are source of valuable material
Hanuman langurs live sympatrically with Bonnet macaques (Macaca radiata), toque macaque (Macaca sinica), and hooded leaf monkeys (Trachypithecus johnii). Each species occupies a distinct niche, therefore, they are able to live with one another with little to no resource competition. Soapberry bug nymphs (Leptocoris augur) rely on Hanuman langurs to remove fruit casings, enabling them to eat.
Ecosystem Impact: disperses seeds
Commensal/Parasitic Species:
Hanuman langurs are primarily herbivores. Their diet is composed of leaves (52-61%), fruits (15-25%), flowers (4-13%), insects (0.4-3%), and other foods such as bark, gum, and soil (9-16%) (Gron, 2008). More developed leaves are preferred over young leaves. They are not highly selective foragers, and consume human food when available. In times of food shortage, they are known to consume bark.
Animal Foods: insects
Plant Foods: leaves; wood, bark, or stems; seeds, grains, and nuts; fruit; flowers; lichens
Primary Diet: herbivore (Folivore )
The geographic range of Semnopithecus entellus (Hanuman langur) spans from Kashmir in north India and the Himalayas in Nepal, Bhutan, and Tibet south to Sri Lanka, east to Bangladesh and west to the Indus valley in Pakistan (Gron, 2008). It is thought that a single breeding pair resulted in the population found in southeast Bangladesh.
Biogeographic Regions: oriental (Introduced , Native )
Hanuman langurs are found in a wide variety of habitats, ranging from arid to tropical evergreen rainforests. They are also known to live in close proximity to humans, including the city of Jodhpur, India, which has over a million inhabitants (Gron, 2008). They are forest dwelling primates in India but are found only in forest openings in Bangladesh (Farid Ahsan and Reza Khan, 2006). The amount of rainfall varies greatly throughout their range (10 to 200 cm). Hanuman langurs are able to withstand a wide range of temperatures, from -7˚C to 46˚C, and spend about 80% of their time on the ground.
Habitat Regions: temperate ; tropical ; terrestrial
Terrestrial Biomes: savanna or grassland ; forest ; rainforest ; scrub forest
Other Habitat Features: urban ; suburban
In captivity Hanuman langurs often live into their early thirties. In the wild, males can live to 18 years old, and females can live to 30 years old.
Typical lifespan
Status: wild: 18 to 30 years.
Typical lifespan
Status: captivity: >30 (high) years.
Hanuman langurs have brownish gray fur, with a tinge of red on their dorsal surface and white fur on their ventral surface. Their feet, hands, face, and ears are black, and their face is framed with white fur. Their tail is usually longer than the body, with a white tip. Infants are born with fine, dark brown or black fur. Their skin is pale, but darkens to black by three months old. They are sexually dimorphic, with males being slightly larger than females. Males weigh about 13 kg and females weigh about 9.9 kg. Excluding their tail, males are about 64 cm long, and females are about 58.5 cm long. Male Hanuman langur tails average 91.0 cm and those of females average 86 cm. They have 32 teeth and their dental formula is 2/2 1/1 2/2 3/3.
Range mass: 9.9 to 13 kg.
Range length: 58.5 to 64 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
Hanuman langurs are preyed upon by leopards (Panthera pardus), dholes (Cuon alpinus), tigers (Panthera tigris), wolves (Canis lupus), and golden jackals (Canis aureus). They sleep in the upper forest canopy to avoid predators while resting; however, deforestation has reduced the number of roosting trees, giving predators easier access to langurs, potentially increasing predator induced mortality (Gron, 2008).
Known Predators:
Hanuman langurs live in both polygynous and polygynandrous groups, and unpaired males form bachelor groups. Male dominance is usually determined through fighting, whereas younger, sexually mature females are higher ranking, and decrease in rank with age. Females advertise estrous via head shaking and presenting the anogenital region to potential mates. Females continue mating during gestation to prevent infanticide by dominant males.
Mating System: polygynous ; polygynandrous (promiscuous)
Females typically reach sexual maturity by 2.9 years of age, with males reaching sexual maturity by 5 years of age. Hanuman langurs breed between July and October, and parturition occurs between February and April. Gestation lasts for 200 to 212 days, after which a single infant is usually born. Although rare, females may also give birth to twins.
Breeding interval: Hanuman langurs breed once annually.
Breeding season: Varies by locations, but often falls between July to October.
Range number of offspring: 1 to 2.
Range gestation period: 200 to 212 days.
Range weaning age: 8.6 to 13 months.
Range time to independence: 1 to 2 years.
Average age at sexual or reproductive maturity (female): 2.9 years.
Average age at sexual or reproductive maturity (male): 5 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous
Infant Hanuman langurs spend the first week of life with their mothers. After that, infants are also cared for by other females that have recently given birth to young; however, the mother still provides most of the care. By six weeks old, infants begin eating on their own. Weaning doesn’t begin until 8 months old and is complete by 13 months old. Between the ages of 9 to 12 months, infants are only around their mother 20% of the time. Males are forced to disperse before they become sexually mature, while females stay with their natal group. Hanuman langurs are independent by 2 years old.
Mothers are very protective of their infants, which often remain at the center of the group for increased protection. Females from surrounding groups sometimes kidnap infants, however, mothers often risk their lives to retrieve their offspring.
Parental Investment: altricial ; female parental care ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female); post-independence association with parents
The northern plains gray langur (Semnopithecus entellus), also known as the sacred langur, Bengal sacred langur and Hanuman langur, is a species of primate in the family Cercopithecidae.
The northern plains gray langur belongs to the genus Semnopithecus along with the other Indian langurs. The southern plains gray langur was once classified as a subspecies of S. entellus, i.e., S. entellus dussumieri and later regarded as a separate species, i.e., S. dussumieri, but is now regarded as an invalid taxon.[3][4][5] Most of the specimens that had been regarded as Semnopithecus dussumieri fall within the revised range of Semnopithecus entellus.[6]
The fur of adults is mostly light colored, with darker fur on the back and limbs, and the face, ears, hands and feet are all black. Infants are brown.[7] Body size excluding tail ranges from 45.1 cm (17.8 in) to 78.4 cm (30.9 in) long, and the tail length is between 80.3 cm (31.6 in) and 111.8 cm (44.0 in).[7][6] Adult males weigh between 16.9 kg (37 lb) and 19.5 kg (43 lb) while adult females weigh between 9.5 kg (21 lb) and 16.1 kg (35 lb).[6][7]
The range of the northern plains gray langur covers a large portion of India south of the Himalayas south to the Tapti River and the Krishna River.[6][7] It is thought to have been introduced to western Bangladesh by Hindu pilgrims on the bank of the Jalangi River.[2]
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The northern plains gray langur is diurnal, and is both terrestrial and arboreal.[7] Its natural habitats are subtropical or tropical dry forests and subtropical or tropical dry shrubland.[2] Females groom members of both sexes but males do not groom others.[7]
The northern plains gray langur can live in several different types of groups. It can live in groups of multiple males and females, one male and multiple females or multiple males with no females, and males can also live alone without a group.[7] Single male groups are most common.[7] Group size can exceed 100 monkeys.[7] Upon reaching maturity, males typically emigrate from their natal group while females typically remain.[6][7] Young adult females are typically dominant over older females.[6] When a new male takes over a group it may engage in infanticide of young fathered by the previous male or males, but this is less common when the takeover occurs slowly over several months.[6][7]
The northern plains gray langur eats primarily fruits and leaves.[7] It is able to survive on mature leaves, which is a key to its ability to survive throughout the dry season.[6] It also eats seeds, flowers, buds, bark and insects, including caterpillars.[6] It is also fed fruits and vegetables by humans, and some groups get a substantial portion of their diets from food provided by temples and from raiding crops.[7]
Groups that have access to abundant food year-round, for example those that are provisioned by temples or are able to raid crops year-round, also breed throughout the year.[6] Other groups, such as those living in forests, typically give birth between December and May.[6] The gestation period is about 200 days.[6] Females other than the mother alloparent the infant for the first month of its life.[6] Weaning occurs at about 1 year and males reach maturity at about 6 to 7 year old.[6]
The northern plains gray langur often associates with chital deer. Both species respond to each other's alarm calls.[7] The chital seem to benefit from the vigilance of male langurs watching for predators in the trees, while the langurs seem to benefit from the chital's better senses of smell and hearing.[6] It also has been observed engaging in grooming sessions with rhesus macaques.[8]
The northern plains gray langur is listed as least concern on the IUCN Red List, it is threatened by habitat loss.[2] The northern plains gray langur adapts to many habitats and the Hindu religion considers the northern plains gray langur to be sacred.[7] Hence it has large population within India, including within towns and cities.[7] It is subject to some threats, including road kill, attacks by dogs, forest fires and diseases caught from domestic animals.[2][7] It is sometimes hunted for food, especially within the states of Odisha and Andhra Pradesh and is sometimes killed by humans to prevent it from raiding crops.[2]
Captive gray langurs are used in Delhi to scare off rhesus macaques, which steal from and sometimes attack people.[9][10]
The northern plains gray langur (Semnopithecus entellus), also known as the sacred langur, Bengal sacred langur and Hanuman langur, is a species of primate in the family Cercopithecidae.
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