Gray langurs, also called Hanuman langurs and Hanuman monkeys, are
Old World monkey
Old World monkey is the common English name for a family of primates known taxonomically as the Cercopithecidae (). Twenty-four genera and 138 species are recognized, making it the largest primate family. Old World monkey genera include baboons ...
s native to the
Indian subcontinent
The Indian subcontinent is a list of the physiographic regions of the world, physiographical region in United Nations geoscheme for Asia#Southern Asia, Southern Asia. It is situated on the Indian Plate, projecting southwards into the Indian O ...
constituting the genus ''Semnopithecus''. Traditionally only one species ''Semnopithecus entellus'' was recognized, but since about 2001, additional species have been recognized. The taxonomy has been in flux, but currently eight species are recognized.
Gray langurs are fairly
terrestrial
Terrestrial refers to things related to land or the planet Earth.
Terrestrial may also refer to:
* Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...
, inhabiting forest, open lightly wooded habitats, and urban areas on the Indian subcontinent. Most species are found at low to moderate altitudes, but the
Nepal gray langur
The Nepal gray langur (''Semnopithecus schistaceus'') is a gray langur endemic to the Himalayas in Nepal, far southwestern Tibet, northern India, northern Pakistan, Bhutan and possibly Afghanistan. It is found in forests at an elevation of . Its ...
and
Kashmir gray langur
The Kashmir gray langur (''Semnopithecus ajax'') is an Old World monkey, one of the langur species. It is a leaf-eating monkey.
It has been reported from Jammu and Kashmir and Himachal Pradesh in northwestern India but evidence indicates it only ...
occur up to in the
Himalaya
The Himalayas, or Himalaya (; ; ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the planet's highest peaks, including the very highest, Mount Everest. Over 100 ...
s.
Characteristics
These langurs are largely gray (some more yellowish), with a black face and ears. Externally, the various species mainly differ in the darkness of the hands and feet, the overall color and the presence or absence of a crest. Typically all north Indian gray langurs have their tail tips looping towards their head during a casual walk whereas all south Indian and Sri Lankan gray langurs have an inverted "U" shape or a "S" tail carriage pattern. There are also significant variations in the size depending on the sex, with the male always larger than the female. The head-and-body length is from . Their tails, at are always longer than their bodies. Langurs from the southern part of their range are smaller than those from the north. At , the heaviest langur ever recorded was a male
Nepal gray langur
The Nepal gray langur (''Semnopithecus schistaceus'') is a gray langur endemic to the Himalayas in Nepal, far southwestern Tibet, northern India, northern Pakistan, Bhutan and possibly Afghanistan. It is found in forests at an elevation of . Its ...
. The larger gray langurs are rivals for the largest species of monkey found in Asia. The average weight of gray langurs is in the males and in the females.
Langurs mostly walk quadrupedally and spend half of their time on the ground and the other half in trees. They will also make bipedal hops, climbing and descending supports with the body upright, and leaps. Langurs can leap horizontally and in descending.
Taxonomy
Traditionally, only ''Semnopithecus entellus'' was recognized as a species, the remainder all being treated as
subspecies
In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...
. In 2001, it was proposed that seven species should be recognized. This was followed in ''
Mammal Species of the World
''Mammal Species of the World: A Taxonomic and Geographic Reference'' is a standard reference work in mammalogy giving descriptions and bibliographic data for the known species of mammals. It is now in its third edition, published in late 2005, ...
'' in 2005, though several of the seven species
intergrade
In zoology, intergradation is the way in which two distinct subspecies are connected via areas where populations are found that have the characteristics of both. There are two types of intergradation: primary and secondary intergradation.
Primar ...
, and alternative treatments exist where only two species (a northern and a southern) are recognized.
Phylogenetic
In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...
evidence supports at least three species: a north Indian, a south Indian and a Sri Lankan one.
It has been suggested that the ''
Semnopithecus priam
The tufted gray langur (''Semnopithecus priam''), also known as Madras gray langur, and Coromandel sacred langur, is an Old World monkey, one of the species of langurs. This, like other gray langurs, is mainly a leaf-eating monkey. It is found i ...
thersites'' is worthy of treatment as a species rather than a subspecies, but at present this is based on limited evidence. During a study based on external
morphology
Morphology, from the Greek and meaning "study of shape", may refer to:
Disciplines
*Morphology (archaeology), study of the shapes or forms of artifacts
*Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...
and
ecological niche modelling
Species distribution modelling (SDM), also known as environmental (or ecological) niche modelling (ENM), habitat modelling, predictive habitat distribution modelling, and range mapping uses computer algorithms to predict the distribution of a spec ...
in
Peninsular India
South India, also known as Dakshina Bharata or Peninsular India, consists of the peninsular southern part of India. It encompasses the Indian states of Andhra Pradesh, Karnataka, Kerala, Tamil Nadu, and Telangana, as well as the union territo ...
six main types were found, but continued to label all as subspecies. Coat color is highly variable, possible due to
phenotypic plasticity
Phenotypic plasticity refers to some of the changes in an organism's behavior, morphology and physiology in response to a unique environment. Fundamental to the way in which organisms cope with environmental variation, phenotypic plasticity encompa ...
and therefore of questionable value in species delimitation.
It has been suggested that ''
Trachypithecus
The lutungs, langurs, or leaf monkeys are a group of Old World monkeys in the genus ''Trachypithecus'' (derived from Greek , meaning "rough" and , meaning "monkey"). Their range is much of Southeast Asia (northeast India, Vietnam, southern Chin ...
'' should be considered only a subgenus of ''Semnopithecus''. If maintaining the two as separate
monophyletic
In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...
genera, the
purple-faced langur
The purple-faced langur (''Semnopithecus vetulus''), also known as the purple-faced leaf monkey, is a species of Old World monkey that is endemic to Sri Lanka. The animal is a long-tailed arboreal species, identified by a mostly brown appearance, ...
and
Nilgiri langur
The Nilgiri langur (''Semnopithecus johnii'') is a langur (a type of Old World monkey) . This primate has glossy black fur on its body and golden brown fur on its head. It is similar in size and long-tailed like the gray langurs. Females have a ...
belong in ''Semnopithecus'' instead of their former genus ''Trachypithecus''. At present it is unclear where the ''T. pileatus'' species group (consisting of the
capped langur
The capped langur (''Trachypithecus pileatus'') is a species of primate in the family Cercopithecidae. It is native to Bangladesh, Bhutan, India, and Myanmar. Its natural habitat is subtropical or tropical dry forests. It is threatened by habita ...
,
Shortridge's langur
The Shortridge's langur (''Trachypithecus shortridgei'') is a lutung native to Burma and China.
References
External links
Shortridge's langur
Primates of Southeast Asia
Mammals of Myanmar
Mammals of China
Fauna of Yunnan
Endangered f ...
and
Gee's golden langur
Gee's golden langur (''Trachypithecus geei''), also known as simply the golden langur, is an Old World monkey found in a small region of Western Assam, India and in the neighboring foothills of the Black Mountains of Bhutan. Long considered sac ...
) belongs, as available
mtDNA
Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial DNA ...
data place it in ''Semnopithecus'', while
Y chromosome
The Y chromosome is one of two sex chromosomes (allosomes) in therian mammals, including humans, and many other animals. The other is the X chromosome. Y is normally the sex-determining chromosome in many species, since it is the presence or abse ...
data place it in ''Trachypithecus''. A possible explanation for this is that the ''T. pileatus'' species group is the result of fairly recent
hybridization
Hybridization (or hybridisation) may refer to:
*Hybridization (biology), the process of combining different varieties of organisms to create a hybrid
*Orbital hybridization, in chemistry, the mixing of atomic orbitals into new hybrid orbitals
*Nu ...
between ''Semnopithecus'' and ''Trachypithecus''.
As of 2005, the authors of ''
Mammal Species of the World
''Mammal Species of the World: A Taxonomic and Geographic Reference'' is a standard reference work in mammalogy giving descriptions and bibliographic data for the known species of mammals. It is now in its third edition, published in late 2005, ...
'' recognized the following seven ''Semnopithecus'' species
*
Nepal gray langur
The Nepal gray langur (''Semnopithecus schistaceus'') is a gray langur endemic to the Himalayas in Nepal, far southwestern Tibet, northern India, northern Pakistan, Bhutan and possibly Afghanistan. It is found in forests at an elevation of . Its ...
''Semnopithecus schistaceus''
*
Kashmir gray langur
The Kashmir gray langur (''Semnopithecus ajax'') is an Old World monkey, one of the langur species. It is a leaf-eating monkey.
It has been reported from Jammu and Kashmir and Himachal Pradesh in northwestern India but evidence indicates it only ...
''Semnopithecus ajax''
*
Tarai gray langur
The Tarai gray langur (''Semnopithecus hector'') is an Old World monkey, and was formerly considered a subspecies of the northern plains gray langur. The species is listed as near threatened, as there are probably not many more than 10,000 matur ...
''Semnopithecus hector''
*
Northern plains gray langur
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.
Taxonomy
The northern plains gray langur belongs to th ...
''Semnopithecus entellus''
*
Black-footed gray langur
The black-footed gray langur (''Semnopithecus hypoleucos'') is an Old World monkey, one of the species of langurs. Found in southern India, this, like other gray langurs, is a leaf-eating monkey.
Taxonomy
The black-footed gray langur was prev ...
''Semnopithecus hypoleucos''
*
Southern plains gray langur
Southern plains gray langur was the common name ascribed to ''Semnopithecus dussumieri'' by ''Mammal Species of the World'' (3rd edition) in 2005. Along with several other ''Semnopithecus'', it had been previously considered a subspecies of the ...
''Semnopithecus dussumieri''
*
Tufted gray langur
The tufted gray langur (''Semnopithecus priam''), also known as Madras gray langur, and Coromandel sacred langur, is an Old World monkey, one of the species of langurs. This, like other gray langurs, is mainly a leaf-eating monkey. It is found i ...
''Semnopithecus priam''
Results of analysis of mitochondrial
cytochrome b
Cytochrome b within both molecular and cell biology, is a protein found in the mitochondria of eukaryotic cells. It functions as part of the electron transport chain and is the main subunit of transmembrane cytochrome bc1 and b6f complexes.
F ...
gene and two
nuclear DNA
Nuclear DNA (nDNA), or nuclear deoxyribonucleic acid, is the DNA contained within each cell nucleus of a eukaryotic organism. It encodes for the majority of the genome in eukaryotes, with mitochondrial DNA and plastid DNA coding for the rest. It ...
-encoded genes of several colobine species revealed that Nilgiri and purple-faced langurs cluster with gray langur, while ''Trachypithecus'' species form a distinct clade.
Since then, two other species have been moved from ''Trachypithecus'' to ''Semnopithecus'':
*
Purple-faced langur
The purple-faced langur (''Semnopithecus vetulus''), also known as the purple-faced leaf monkey, is a species of Old World monkey that is endemic to Sri Lanka. The animal is a long-tailed arboreal species, identified by a mostly brown appearance, ...
''Semnopithecus vetulus''
*
Nilgiri langur
The Nilgiri langur (''Semnopithecus johnii'') is a langur (a type of Old World monkey) . This primate has glossy black fur on its body and golden brown fur on its head. It is similar in size and long-tailed like the gray langurs. Females have a ...
''Semnopithecus johnii''
In addition, ''Semnopithecus dussumieri'' has been determined to be invalid. Most of the range that had been considered ''S. dussumieri'' is now considered ''S. entellus''.
Thus the current generally accepted species within the genus ''Semnopithecus'' are:
*
Northern plains gray langur
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.
Taxonomy
The northern plains gray langur belongs to th ...
(also known as the Hanuman langur or Bengal gray langur) ''Semnopithecus entellus''
*
Kashmir gray langur
The Kashmir gray langur (''Semnopithecus ajax'') is an Old World monkey, one of the langur species. It is a leaf-eating monkey.
It has been reported from Jammu and Kashmir and Himachal Pradesh in northwestern India but evidence indicates it only ...
''Semnopithecus ajax''
*
Tarai gray langur
The Tarai gray langur (''Semnopithecus hector'') is an Old World monkey, and was formerly considered a subspecies of the northern plains gray langur. The species is listed as near threatened, as there are probably not many more than 10,000 matur ...
''Semnopithecus hector''
*
Black-footed gray langur
The black-footed gray langur (''Semnopithecus hypoleucos'') is an Old World monkey, one of the species of langurs. Found in southern India, this, like other gray langurs, is a leaf-eating monkey.
Taxonomy
The black-footed gray langur was prev ...
''Semnopithecus hypoleucos''
*
Tufted gray langur
The tufted gray langur (''Semnopithecus priam''), also known as Madras gray langur, and Coromandel sacred langur, is an Old World monkey, one of the species of langurs. This, like other gray langurs, is mainly a leaf-eating monkey. It is found i ...
''Semnopithecus priam''
*
Nepal gray langur
The Nepal gray langur (''Semnopithecus schistaceus'') is a gray langur endemic to the Himalayas in Nepal, far southwestern Tibet, northern India, northern Pakistan, Bhutan and possibly Afghanistan. It is found in forests at an elevation of . Its ...
''Semnopithecus schistaceus''
*
Purple-faced langur
The purple-faced langur (''Semnopithecus vetulus''), also known as the purple-faced leaf monkey, is a species of Old World monkey that is endemic to Sri Lanka. The animal is a long-tailed arboreal species, identified by a mostly brown appearance, ...
''Semnopithecus vetulus''
*
Nilgiri langur
The Nilgiri langur (''Semnopithecus johnii'') is a langur (a type of Old World monkey) . This primate has glossy black fur on its body and golden brown fur on its head. It is similar in size and long-tailed like the gray langurs. Females have a ...
''Semnopithecus johnii''
A 2013 genetic study indicated that while ''S. entellus'', ''S. hypoleucos'', ''S. priam'' and ''S. johnii'' are all valid taxa, there has been
hybridization
Hybridization (or hybridisation) may refer to:
*Hybridization (biology), the process of combining different varieties of organisms to create a hybrid
*Orbital hybridization, in chemistry, the mixing of atomic orbitals into new hybrid orbitals
*Nu ...
between ''S. priam'' and ''S. johnii''.
It also indicated that there has been some hybridization between ''S. entellus'' and ''S. hypoleucos'' where their ranges overlap, and a small amount of hybridization between ''S. hypoleucos'' and ''S. priam''. It also suggested that ''S. priam'' and ''S. johnii'' diverged from each other fairly recently.
Distribution and habitat
The entire distribution of all gray langur species stretches from the
Himalayas
The Himalayas, or Himalaya (; ; ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the planet's highest peaks, including the very highest, Mount Everest. Over 100 ...
in the north to Sri Lanka in the south, and from
Bangladesh
Bangladesh (}, ), officially the People's Republic of Bangladesh, is a country in South Asia. It is the eighth-most populous country in the world, with a population exceeding 165 million people in an area of . Bangladesh is among the mos ...
in the east to Pakistan in the west. They possibly occur in Afghanistan. The bulk of the gray langur distribution is within India, and all seven currently recognized species have at least a part of their range in this country.
Gray langurs can adapt to a variety of habitats. They inhabit
arid
A region is arid when it severely lacks available water, to the extent of hindering or preventing the growth and development of plant and animal life. Regions with arid climates tend to lack vegetation and are called xeric or desertic. Most ar ...
habitats like deserts, tropical habitats like tropical rainforests and temperate habitats like coniferous forests, deciduous habitats and mountains habitats. They are found at sea level to altitudes up to . They can adapt well to human settlements, and are found in villages, towns and areas with housing or agriculture. They live in densely populated cities like
Jodhpur
Jodhpur (; ) is the second-largest city in the Indian state of Rajasthan and officially the second metropolitan city of the state. It was formerly the seat of the princely state of Jodhpur State. Jodhpur was historically the capital of the Ki ...
, which has a population numbering up to a million.
Ecology and behavior
Gray langurs are diurnal. They sleep during the night in trees but also on man-made structures like towers and electric poles when in human settlements. When resting in trees, they generally prefer the highest branches.
Ungulate
Ungulates ( ) are members of the diverse clade Ungulata which primarily consists of large mammals with hooves. These include odd-toed ungulates such as horses, rhinoceroses, and tapirs; and even-toed ungulates such as cattle, pigs, giraffes, cam ...
s like
bovine
Bovines (subfamily Bovinae) comprise a diverse group of 10 genera of medium to large-sized ungulates, including cattle, bison, African buffalo, water buffalos, and the four-horned and spiral-horned antelopes. The evolutionary relationship betwee ...
and
deer
Deer or true deer are hoofed ruminant mammals forming the family Cervidae. The two main groups of deer are the Cervinae, including the muntjac, the elk (wapiti), the red deer, and the fallow deer; and the Capreolinae, including the reindeer ...
will eat food dropped by foraging langurs. Langurs are preyed upon by
leopards
The leopard (''Panthera pardus'') is one of the five extant species in the genus '' Panthera'', a member of the cat family, Felidae. It occurs in a wide range in sub-Saharan Africa, in some parts of Western and Central Asia, Southern Russia, ...
,
dhole
The dhole (''Cuon alpinus''; ) is a canid native to Central, South, East and Southeast Asia. Other English names for the species include Asian wild dog, Asiatic wild dog, Indian wild dog, whistling dog, red dog, red wolf, and mountain wolf. It ...
s and
tigers
The tiger (''Panthera tigris'') is the largest living cat species and a member of the genus ''Panthera''. It is most recognisable for its dark vertical stripes on orange fur with a white underside. An apex predator, it primarily preys on un ...
.
Wolves
The wolf (''Canis lupus''; plural, : wolves), also known as the gray wolf or grey wolf, is a large Canis, canine native to Eurasia and North America. More than thirty subspecies of Canis lupus, subspecies of ''Canis lupus'' have been reco ...
,
jackal
Jackals are medium-sized canids native to Africa and Eurasia. While the word "jackal" has historically been used for many canines of the subtribe canina, in modern use it most commonly refers to three species: the closely related black-backed ...
s,
Asian black bear
The Asian black bear (''Ursus thibetanus''), also known as the Asiatic black bear, moon bear and white-chested bear, is a medium-sized bear species native to Asia that is largely adapted to an arboreal lifestyle. It lives in the Himalayas, sout ...
s and
pythons
The Pythonidae, commonly known as pythons, are a family of nonvenomous snakes found in Africa, Asia, and Australia. Among its members are some of the largest snakes in the world. Ten genera and 42 species are currently recognized.
Distribution ...
may also prey on langurs.
Diet
Gray langurs are primarily
herbivore
A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...
s. However, unlike some other colobines they do not depend on leaves and leaf buds of herbs, but will also eat
conifer
Conifers are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single ...
ous needles and cones, fruits and fruit buds, evergreen petioles, shoots and roots, seeds, grass,
bamboo
Bamboos are a diverse group of evergreen perennial flowering plants making up the subfamily Bambusoideae of the grass family Poaceae. Giant bamboos are the largest members of the grass family. The origin of the word "bamboo" is uncertain, bu ...
,
fern
A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes except t ...
rhizomes,
moss
Mosses are small, non-vascular flowerless plants in the taxonomic division Bryophyta (, ) '' sensu stricto''. Bryophyta (''sensu lato'', Schimp. 1879) may also refer to the parent group bryophytes, which comprise liverworts, mosses, and hor ...
es, and
lichen
A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship. Although they occasionally drink, langurs get most of their water from the moisture in their food.
Social structure
Gray langurs exist in three types of groups:
* one-male groups, comprising one adult male, several females and offspring;
* multiple-male groups, comprising males and females of all ages;
* all-male groups.
All-male groups tend to be the smallest of the groups and can consist of adults, subadults, and juveniles. Some populations have only multiple-male groups as mixed sex groups, while others have only one-male groups as mixed sexed groups.
Some evidence suggests multiple-male groups are temporary and exist only after a takeover, and subsequently split into one-male and all-male groups.
Social hierarchies exist for all group types. In all-male groups, dominance is attained through aggression and mating success. With sexually mature females, rank is based on physical condition and age. The younger the female, the higher the rank. Dominance rituals are most common among high-ranking langurs. Most changes in social rank in males take place during changes in group members. An adult male may remain in a one-male group for 45 months. The rate of male replacement can occur quickly or slowly depending on the group.
Females within a group are matrilineally related. Female memberships are also stable, but less so in larger groups. Relationships between the females tend to be friendly. They will do various activities with each together, such as foraging, traveling and resting. They will also groom each other regardless of their rank. However, higher-ranking females give out and receive grooming the most. In addition, females groom males more often than the other way around. Male and female relationships are usually positive. Relationships between males can range from peaceful to violent. While females remain in their natal groups, males will leave when they reach adulthood. Relationships between groups tend to be hostile. High-ranking males from different groups will display, vocalize, and fight among themselves.
Reproduction and parenting
In one-male groups, the resident male is usually the sole breeder of the females and sires all the young. In multiple-male groups, the highest-ranking male fathers most of the offspring, followed by the next-ranking males and even outside males will father young. Higher-ranking females are more reproductively successful than lower-ranking ones.
Female gray langurs do not make it obvious that they are in
estrous
The estrous cycle (, originally ) is the set of recurring physiological changes that are induced by reproductive hormones in most mammalian therian females. Estrous cycles start after sexual maturity in females and are interrupted by anestrous p ...
. However, males are still somehow able to deduce the reproduction state of females. Females signal that they are ready to mate by shuddering the head, lowering the tail, and presenting their anogenital regions. Such solicitations do not always lead to copulation. When langurs mate, they are sometimes disrupted by other group members. Females have even been recorded mounting other females.
The
gestation
Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregna ...
period of gray langur lasts around 200 days, at least at Jodhpur, India. In some areas, reproduction is year-around. Year-round reproduction appears to occur in populations that capitalize on human-made foods. Other populations have seasonal reproduction.
Infanticide
Infanticide (or infant homicide) is the intentional killing of infants or offspring. Infanticide was a widespread practice throughout human history that was mainly used to dispose of unwanted children, its main purpose is the prevention of reso ...
is common among gray langurs. Most infanticidal langurs are males that have recently immigrated to a group and driven out the prior male. These males only kill infants that are not their own. Infanticide is more commonly reported in one-male groups, perhaps because one male monopolizing matings drives the evolution of this trait. In multiple-male groups, the costs for infanticidal males are likely to be high as the other males may protect the infants and they can't ensure that they'll sire young with other males around. Nevertheless, infanticide does occur in these groups, and is suggested that such practices serve to return a female to estrous and gain the opportunity to mate.
Females usually give birth to a single infant, although twins do occur. Most births occur during the night. Infants are born with thin, dark brown or black hair and pale skin. Infants spend their first week attached to their mothers' chests and mostly just suckle or sleep. They do not move much in terms of locomotion for the first two weeks of their life. As they approach their sixth week of life, infants vocalize more. They use squeaks and shrieks to communicate stress. In the following months, the infants are capable of quadrupedal locomotion and can walk, run and jump by the second and third months.
Alloparenting
Alloparenting (also referred to as alloparental care) is a term used to classify any form of parental care provided by an individual towards young that aren't its own direct offspring. These are often referred to as "non-descendant" young, even th ...
occurs among langurs, starting when the infants reach two years of age. The infant will be given to the other females of the group. However, if the mother dies, the infant usually follows. Langurs are weaned by 13 months.
Vocalizations
Gray langurs are recorded to make a number of vocalizations:
*loud calls or whoops made only by adult males during displays;
*harsh barks made by adult and subadult males when surprised by a predator;
*cough barks made by adults and subadults during group movements;
*grunt barks made mostly by adult males during group movements and agonistic interactions;
*rumble screams made in agonistic interactions;
*pant barks made with loud calls when groups are interacting;
*grunts made in many different situations, usually in agonistic ones;
*honks made by adult males when groups are interacting;
*rumbles made during approaches, embraces, and mounts;
*hiccups made by most members of a group when they find another group.
Status and conservation
Gray langurs have stable populations in some areas and declining ones in others. Both the
black-footed gray langur
The black-footed gray langur (''Semnopithecus hypoleucos'') is an Old World monkey, one of the species of langurs. Found in southern India, this, like other gray langurs, is a leaf-eating monkey.
Taxonomy
The black-footed gray langur was prev ...
and
Kashmir gray langur
The Kashmir gray langur (''Semnopithecus ajax'') is an Old World monkey, one of the langur species. It is a leaf-eating monkey.
It has been reported from Jammu and Kashmir and Himachal Pradesh in northwestern India but evidence indicates it only ...
are considered
threatened
Threatened species are any species (including animals, plants and fungi) which are vulnerable to endangerment in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of ''critical depensat ...
. The latter is the rarest species of gray langur, with less than 250 mature individuals remaining.
In India, gray langurs number at around 300,000. India has laws prohibiting the capturing or killing of langurs, but they are still hunted in some parts of the country. Enforcement of these laws has proven to be difficult and it seems most people are unaware of their protection. Populations are also threatened by mining, forest fires and deforestation for wood.
Langurs can be found near roads and can become victims of automobile accidents. This happens even in protected areas, with deaths by automobile collisions making nearly a quarter of mortality in Kumbhalgarh Wildlife Sanctuary in Rajasthan, India. Langurs are considered sacred in the Hindu religion and are sometimes kept for religious purposes by Hindu priests and for roadside performances. However, some religious groups use langurs as food and medicine, and parts of gray langurs are sometimes kept as amulets for good luck.
Because of their sacred status and their less aggressive behavior compared to other primates, langurs are generally not considered pests in many parts of India. Despite this, research in some areas show high levels of support for the removal of langurs from villages, their sacred status no longer important. Langurs will raid crops and steal food from houses, and this causes people to persecute them. While people may feed them in temples, they do not extend such care to monkeys at their homes. Langurs stealing and biting people to get food in urban areas may also contribute to more persecutions.
See also
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Lion-tailed macaque
The lion-tailed macaque (''Macaca silenus''), also known as the wanderoo, is an Old World monkey endemic to the Western Ghats of South India.
Characteristics
Lion-tailed macaques are covered in black fur, and have a striking gray or silver ...