Animal Diversity Web

Ge­o­graphic Range

Tra­chyp­ithe­cus johnii (Nil­giri lan­gurs) are en­demic to the south­ern por­tions of the West­ern Ghats, a moun­tain range in the south of India. They are found be­tween 8°N and 12°N lat­i­tude and 76°E and 77.5°E lon­gi­tude. (Malviya, et al., 2011; Ram, 2007)

• Biogeographic Regions
• oriental
  • native

Habi­tat

Tra­chyp­ithe­cus johnii typ­i­cally in­hab­its a wide range of for­est habi­tats in the West­ern Ghats. They are found pri­mar­ily in sec­ondary moist de­cid­u­ous forests and wet ever­green to semi ever­green forests. They pre­fer lo­ca­tions that are as close to water, and as far away from hu­mans, as pos­si­ble.

Nil­giri lan­gurs are an ar­bo­real species, sleep­ing in the mid­dle or lower canopy in trees of medium height. They re­side in the sholas of the West­ern Ghats. Sholas are nar­row stretches of for­est sur­rounded by grass­lands, nes­tled in val­leys at high el­e­va­tions. Nil­giri lan­gurs live at el­e­va­tions be­tween around 300 and 2,500 me­ters, and are most com­monly found at ap­prox­i­mately 1,400 me­ters. (Malviya, et al., 2011; Poirier, 1969; Ram, 2007; Richard­son, 2005)

• Habitat Regions
• tropical
• terrestrial

• Terrestrial Biomes
• forest
• mountains

• Range elevation

  300 to 2,500 m

  984.25 to ft

• Average elevation

  1,400 m

  ft

Phys­i­cal De­scrip­tion

Tra­chyp­ithe­cus johnii is a colobine mon­key. They share many of the char­ac­ter­is­tic colobine fea­tures, such as a com­plex stom­ach, a re­duced thumb, and a long tail. Nil­giri lan­gurs have a shiny black coat with a red­dish-brown to gold head. New­borns are red­dish-brown for up to ten weeks, when they gain the hue of the adults.

Sim­i­lar to pur­ple faced lan­gurs, Nil­giri lan­gurs have dark faces and white side­burns. Fe­males have white patches on their thighs that dis­tin­guish them from males.

Nil­giri lan­gurs are sex­u­ally di­mor­phic, with males slightly larger than fe­males. The males of this species have a total body length that ranges be­tween 78 to 80 cm, weigh­ing be­tween 9.1 and 14.8 kg. The fe­males’ lengths range from 58 to 60 cm, weigh­ing be­tween 10.9 and 12 kg. The tails of both males and fe­males vary in length be­tween 68.5 and 96.5 cm. (Flea­gle, 1999; Malviya, et al., 2011)

• Other Physical Features
• endothermic
• homoiothermic
• bilateral symmetry

• Sexual Dimorphism
• male larger
• sexes colored or patterned differently

• Range mass

  9.1 to 14.8 kg

  20.04 to 32.60 lb

• Range length

  58 to 80 cm

  22.83 to 31.50 in

Re­pro­duc­tion

Tra­chyp­ithe­cus johnii in­di­vid­u­als are sex­u­ally di­mor­phic, with a male to fe­male body size ratio of 1.2 to 1.0. This in­di­cates mod­est in­tra­sex­ual com­pe­ti­tion among males for fe­male mates.

Though there is lit­tle doc­u­mented in­for­ma­tion about the Nil­giri lan­gur mat­ing sys­tem, it is as­sumed to be sim­i­lar to that of the Hanu­man lan­gur, to which it is closely re­lated. Hanu­man lan­gurs exist in uni-male or multi-male groups. The fre­quency of uni-male groups is de­pen­dent on the abil­ity of in­di­vid­ual males to de­fend and re­tain groups of fe­males. There are small num­bers of fe­males in these uni-male groups be­cause larger num­bers of fe­males above a cer­tain thresh­old are able to exert con­trol over the num­ber of males in their groups. Dis­tance be­tween groups, or pop­u­la­tion den­sity, also has an ef­fect on the pro­por­tion of uni-male to multi-male groups. When groups are more spread out, it is more ad­van­ta­geous for a male to re­main in his cur­rent group than to risk pre­da­tion while trav­el­ing alone to an­other group.

There is ev­i­dence that uni-male groups in­crease fe­male birth rates, in­di­cat­ing that less male-male com­pe­ti­tion is bet­ter for the re­pro­duc­tive suc­cess of fe­male lan­gurs. (Grueter and Van Schaik, 2009; Sri­vas­tava and Dun­bar, 1996)

• Mating System
• polygynous
• polygynandrous (promiscuous)

There is a surge in birth rate for Nil­giri lan­gurs at two points in the year: most no­tably in the months of May and June, and sec­on­dar­ily be­tween Sep­tem­ber and No­vem­ber. This sea­son­al­ity of breed­ing may re­flect a reg­u­lar sea­sonal de­ple­tion of re­sources, which would af­fect fe­males' abil­ity to ovu­late and there­fore con­ceive. This would in­di­cate that Nil­giri lan­gurs breed year-round, but only con­ceive when re­sources are plen­ti­ful. Nil­giri lan­gurs typ­i­cally have only one off­spring at a time.

The length of the ges­ta­tion pe­riod of Nil­giri lan­gurs in the wild is not known, but is as­sumed to be com­pa­ra­ble to the closely re­lated Hanu­man lan­gur, the ges­ta­tion pe­riod for which is 200 days. In cap­tiv­ity, the ges­ta­tion pe­riod for Nil­giri lan­gurs is be­tween 140 and 220 days. At birth, in­fant Nil­giri lan­gurs weigh on av­er­age 0.5 kg. ("Nil­giri lan­gur", 2011; Koenig, et al., 1997; Malviya, et al., 2011; Richard­son, 2005)

Al­though no data exist for Nil­giri lan­gurs specif­i­cally, a re­cent study on the erup­tion of mo­lars in Tra­chyp­ithe­cus spec­i­mens in­di­cated that the erup­tion of the third molar oc­curred be­tween 3 and 5 years of age, in­di­cat­ing an in­di­vid­ual had reached sex­ual ma­tu­rity. (In­g­icco, et al., 2012)

• Key Reproductive Features
• iteroparous
• year-round breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• viviparous

• Breeding interval

  Nilgiri langurs breed throughout the year, with two periods of increased breeding reflecting food availablity.

• Breeding season

  Although limited data are available on potential breeding seasons of Nilgiri langurs, evidence suggests that mating takes place year-round.

• Average number of offspring

  1

• Range gestation period

  140 to 220 days

• Average weaning age

  12 months

• Average age at sexual or reproductive maturity (female)

  3-5 years

• Average age at sexual or reproductive maturity (male)

  3-5 years

Tra­chyp­ithe­cus johnii does not dis­play strong bonds be­tween mother and young com­pared to sim­i­lar species, though nurs­ing lasts al­most a year. Oc­ca­sion­ally, when young in­fants are in dis­tress, their moth­ers will ig­nore the cries for help in an un­usual dis­play of ap­a­thy. One hy­poth­e­sis ex­plains this as a re­sult of the rel­a­tively low threat of preda­tors. In all other ways, how­ever, Nil­giri lan­gur moth­ers are at­ten­tive and nur­tur­ing. For ex­am­ple, off­spring cling to their moth­ers’ bel­lies while mov­ing and even jump­ing, and are also shel­tered by their moth­ers dur­ing rain­storms.

When new­borns are around 10 days old, their moth­ers will per­mit other fe­males to han­dle and care for their young. This oc­curs when the mother wants to feed. One non-ma­ter­nal fe­male could 'baby-sit' the off­spring of up to three moth­ers.

In­fants are weened by the end of one year, and at that point are al­most com­pletely in­de­pen­dent of their moth­ers. Until the end of their first year, Nil­giri lan­gur in­fants spend the ma­jor­ity of their time with their moth­ers or with other close fe­males, only rarely com­ing into con­tact with adult males. (Malviya, et al., 2011; Poirier, 1968)

• Parental Investment
• female parental care
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • provisioning
    • female
  • protecting
    • male
    • female
• post-independence association with parents

Lifes­pan/Longevity

There is no doc­u­mented in­for­ma­tion on the lifes­pan of Nil­giri lan­gurs in the wild, but they can live up to 29 years in cap­tiv­ity. ("Nil­giri lan­gur", 2011)

• Range lifespan
  Status: captivity

  29 (high) years

Be­hav­ior

Tra­chyp­ithe­cus johnii is an ar­bo­real and di­ur­nal species. Dur­ing peak ac­tiv­ity, it en­gages al­ter­na­tively in feed­ing and rest­ing pe­ri­ods. There are a host of other so­cial ac­tiv­i­ties that are vis­i­ble, pri­mar­ily dur­ing rest­ing pe­ri­ods. Ex­am­ples of these are groom­ing, play­ing, chas­ing, watch­ing, fight­ing, mount­ing, ag­gres­sion, and dom­i­nance as­ser­tion.

Nil­giri lan­gurs gen­er­ally live in small fe­male-cen­tric groups. These groups can con­sist of one male and sev­eral fe­males, sev­eral males and sev­eral fe­males, or one or more soli­tary males. Typ­i­cally, the uni-male, multi-fe­male model is the most com­mon. Group sizes have been doc­u­mented be­tween 1 and 27 mem­bers, with an av­er­age of 14 or 15 in­di­vid­u­als. (Malviya, et al., 2011; Oates, et al., 1994; Poirier, 1970a)

Tra­chyp­ithe­cus johnii ex­hibits sub­tle dom­i­nance hi­er­ar­chies. There are two dom­i­nance struc­tures within each group, one for males and one for fe­males. Dom­i­nance struc­tures are not com­pletely rigid, in that dom­i­nance is ex­pressed in the num­ber of times a spe­cific in­di­vid­ual is forced to act sub­or­di­nately to an­other. For ex­am­ple, an alpha fe­male with higher sta­tus may act dom­i­nantly to­wards a beta fe­male the large ma­jor­ity of the time, but would be­have sub­or­di­nately on rare oc­ca­sions. How­ever, a gamma fe­male would usu­ally be­have sub­or­di­nately to­wards a beta fe­male, ex­press­ing dom­i­nance very in­fre­quently.

So­cial sta­tus is more im­por­tant for males than for fe­males. The alpha fe­male dis­plays dom­i­nance mainly in choos­ing pre­ferred feed­ing and sleep­ing sites. The alpha male dis­plays dom­i­nance most no­tice­ably in de­ter­min­ing the trav­el­ing di­rec­tion and tim­ing of the en­tire group, but also in free­dom of choice over daily life. The alpha male can eat with or so­cial­ize with any other mem­ber of the group.

Nil­giri lan­gur males are typ­i­cally more in­volved in dom­i­nance than fe­males, though dom­i­nance be­hav­iors in gen­eral are not par­tic­u­larly fre­quent. In ad­di­tion, ag­gres­sion dur­ing these en­coun­ters is avoided. There is lit­tle com­pe­ti­tion for food or mates, and sub­or­di­nate in­di­vid­u­als are care­ful to avoid po­ten­tially harm­ful sit­u­a­tions. Nil­giri lan­gurs there­fore have a rel­a­tively re­laxed daily life. (Poirier, 1970a)

Nil­giri lan­gurs ex­hibit ter­ri­to­r­ial be­hav­iors when con­fronted by other groups of their species. This de­fense of ter­ri­tory di­rectly in­volves only one adult male of each group. Males de­fend their home areas through phys­i­cal dis­plays, vo­cal­iza­tions, and chases. Con­fronta­tions some­times es­ca­late to phys­i­cal vi­o­lence, leav­ing both de­fend­ing males and non-group males with scars on their faces and bod­ies. In ex­treme cases, male take-overs and in­fan­ti­cide are known to occur. Such ter­ri­to­r­ial in­ter­ac­tions usu­ally take place in the areas where the home ranges of two or more groups over­lap, though Nil­giri lan­gurs usu­ally avoid these over­lap areas when the mem­bers of other groups are pre­sent. (Flea­gle, 1999; Malviya, et al., 2011)

• Key Behaviors
• arboreal
• scansorial
• diurnal
• motile
• nomadic
• territorial
• social
• dominance hierarchies

• Average territory size

  10,000 m^2

Home Range

Tra­chyp­ithe­cus johnii has an av­er­age home range of around 10,000 square me­ters. The size of the home range fluc­tu­ates with qual­ity of habi­tat dur­ing the sea­sons: when pre­ferred food is read­ily avail­able, the range is smaller; when it is more scarce, the home range in­creases. The core area of this species in­cludes feed­ing sites and rest­ing or sleep­ing sites. These sites are cho­sen as close to water and as far away from hu­mans as pos­si­ble.

An ob­ser­va­tional study found that the ter­ri­tory size is es­sen­tially equiv­a­lent to the home range. (Hor­wich, 1972; Malviya, et al., 2011)

Com­mu­ni­ca­tion and Per­cep­tion

Nil­giri lan­gurs com­mu­ni­cate mainly through vo­cal­iza­tion. Vo­cal­iza­tions have many dif­fer­ent func­tions, with var­i­ous calls re­lated to dif­fer­ent so­cial sit­u­a­tions. Vocal com­mu­ni­ca­tions are ob­served dur­ing the main­te­nance of the so­cial hi­er­ar­chy, dur­ing ter­ri­to­r­ial dis­putes, as a part of within-group fe­male-fe­male con­flicts, and fi­nally for male in­ter­ven­tion into such con­flicts.

Nil­giri lan­gurs also com­mu­ni­cate with ol­fac­tory, tac­tile, and vi­sual sig­nals. They are known to en­gage in mouth sniff­ing as a part of feed­ing. This species also ex­hibits nu­mer­ous ex­pres­sions to sig­nal to other species mem­bers. Some ex­am­ples of ex­pres­sions in­clude a threat­en­ing open mouth ges­ture, a sub­mis­sive head shak­ing ges­ture, a friendly play in­vi­ta­tion, and a com­fort­ing out­stretched hand ges­ture di­rected from moth­ers to­wards in­fants. In­stances of tac­tile com­mu­ni­ca­tion in­volve bit­ing, lick­ing, em­brac­ing, stroking, and slap­ping. (Malviya, et al., 2011)

• Communication Channels
• visual
• tactile
• acoustic
• chemical

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

A fo­liv­o­rous species, Nil­giri lan­gurs eat many kinds of leaves, which make up the ma­jor­ity of their diet. They also take in nu­tri­ents from fruits, seeds, nuts, stems, bark, flow­ers, and soil. The only car­niv­o­rous as­pect of their diet is the oc­ca­sional con­sump­tion of in­sects.

Nil­giri lan­gurs pre­fer the leaves of teak trees, Tec­tona gran­dis, and con­sume these larger leaves more fre­quently than oth­ers that oc­ca­sion­ally make up their diet.

Nil­giri lan­gurs are re­ported to choose foods based on di­gestibil­ity; they have a diet that is low in both fiber and veg­etable tan­nin. It is hy­poth­e­sized that they use the soil they con­sume as an antacid, which sta­bi­lizes the pH level of the stom­ach. (Hor­wich, 1972; Malviya, et al., 2011; Oates, et al., 1980)

Nil­giri lan­gurs spend al­most half of their wak­ing hours feed­ing. When eat­ing leaves, they first eat the tips, then they rip off the sides to ex­pose the midrib, which they also con­sume. This is a del­i­cate and de­lib­er­ate process, with one side of each leaf pealed back at a time to ex­pose the midrib of the leaf. Each leaf takes ap­prox­i­mately 30 sec­onds to eat. Dur­ing eat­ing pe­ri­ods, in which Nil­giri lan­gurs take and con­sume leaves al­most con­tin­u­ously, about 5-10 sec­onds are taken be­tween leaves. (Hor­wich, 1972; Malviya, et al., 2011)

• Primary Diet
• herbivore
  • folivore
  • frugivore
  • granivore
  • lignivore

• Animal Foods
• insects

• Plant Foods
• leaves
• wood, bark, or stems
• seeds, grains, and nuts
• fruit
• flowers

• Other Foods
• detritus

Pre­da­tion

Nil­giri lan­gurs have vo­cal­iza­tions for dis­tress, warn­ing, and alarm, each with its own sound and sig­nif­i­cance. They emit high-pitched barks as alarm calls to nearby in­di­vid­u­als, which can be ei­ther short in quick in­ter­vals or longer and con­tin­u­ous. The con­tin­u­ous alarm call usu­ally rep­re­sents a more press­ing haz­ard. In re­sponse to hear­ing ei­ther of the bark­ing alarm calls, Nil­giri lan­gurs will dis­play signs of fear often ac­com­pa­nied by flight.

Nil­giri lan­gurs are rel­a­tively free from pre­da­tion, al­though one doc­u­mented preda­tor is the In­dian wild dog. Hu­mans also hunt these lan­gurs. (Poirier, 1968; Poirier, 1970b; Singh, et al., 2008)

• Known Predators

  • Indian wild dog, Cuon alpinus
  • Humans, Homo sapiens

Ecosys­tem Roles

Of all the pri­mates en­demic to the West­ern Ghats in India, Nil­giri lan­gurs feed on the largest num­ber of plant species. They con­sume over 115 dif­fer­ent species, in­clud­ing at least 58 tree species, 6 shrubs, 13 non-woody plants, 32 vines, and 6 par­a­sitic plants. Fruits, nuts, and seeds are also parts of their di­verse diets, and they func­tion in their ecosys­tem as seed dis­persers. (Malviya, et al., 2011)

• Ecosystem Impact
• disperses seeds

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Tra­chyp­ithe­cus johnii in­di­vid­u­als are poached for var­i­ous pur­poses. Their body parts are sold for use in tra­di­tional med­i­cine and are even ad­ver­tised as com­po­nents of recipes for aphro­disi­acs. In ad­di­tion, they are hunted for their skins, which are used as drum heads. Nil­giri lan­gurs are also cap­tured and sold as pets. While these may be pos­i­tive eco­nomic ef­fects for hu­mans, they have dev­as­tat­ing neg­a­tive con­se­quences for the pop­u­la­tions of Nil­giri lan­gurs that re­main in de­cline. (Malviya, et al., 2011; Singh, et al., 2008)

• Positive Impacts
• pet trade
• food
• body parts are source of valuable material
• source of medicine or drug

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Nil­giri lan­gurs are known as crop pests to cau­li­flower, potato, car­damom, and gar­den poppy farm­ers. How­ever, this neg­a­tive ef­fect on hu­mans may be ex­ac­er­bated by the fact that peo­ple are con­stantly en­croach­ing on the nat­ural habi­tat of Nil­giri lan­gurs by plant­ing crops, min­ing, and build­ing homes. (Malviya, et al., 2011; Singh, et al., 2008)

• Negative Impacts
• crop pest

Con­ser­va­tion Sta­tus

Only 50% of this species’ ter­ri­tory is within the pro­tected area in the West­ern Ghats. Their pop­u­la­tion is es­ti­mated be­tween 5,000 and 15,000 in­di­vid­u­als and less than 10,000 ma­ture in­di­vid­u­als. The two main threats to Nil­giri lan­gurs in­clude the de­struc­tion of their nat­ural habi­tat and poach­ing for var­i­ous pur­poses.

Be­cause of the rel­a­tively small num­ber of ma­ture adult Nil­giri lan­gurs in the world, and be­cause of the de­clin­ing trend in pop­u­la­tion size, they are placed on the IUCN Red List as Vul­ner­a­ble. In ad­di­tion, they have been pro­tected under the In­dian Wildlife Pro­tec­tion Act since 1972. (Malviya, et al., 2011; Singh, et al., 2008)

There is ev­i­dence that the level of human dis­tur­bance, or habi­tat sat­u­ra­tion, cor­re­lates pos­i­tively with in­stances of in­fan­ti­cide in lan­gurs. In ef­fect, human dis­tur­bance low­ers in­stances of fe­male dis­per­sal rel­a­tive to male takeover. When males in­vade and take over a group, lev­els of in­fan­ti­cide are much higher than if fe­males are able to more peace­fully leave their pre­vi­ous groups, which only hap­pens when lan­gurs have not reached the hold­ing ca­pac­ity of their en­vi­ron­ment. This shows the neg­a­tive ef­fects of hu­mans en­croach­ing on the lan­gurs' ter­ri­tory. (Sterck, 1998)

• IUCN Red List

  Vulnerable

• CITES

  Appendix II

Other Com­ments

There is some de­bate over the clas­si­fi­ca­tion of this species, giv­ing rise to con­flict­ing views on its tax­o­nomic place­ment. Some tax­on­o­mists place Nil­giri lan­gurs with Hanu­man lan­gurs, while oth­ers con­sider them a species of Tra­chyp­ithe­cus. Still oth­ers place them in their own genus known as Kasi. Nil­giri lan­gurs are there­fore named Tra­chyp­ithe­cus johnii, Semno­p­ithe­cus johnii, Pres­bytis johnii, and Kasi johnii in var­i­ous sci­en­tific lit­er­a­ture.

This species' var­i­ous com­mon names in­clude: black leaf mon­key, hooded leaf mon­key, In­dian hooded leaf mon­key, John's lan­gur, Nil­giri black lan­gur, and Nil­giri leaf mon­key. (Flea­gle, 1999; Richard­son, 2005)

Con­trib­u­tors

Claire Solomon (au­thor), Yale Uni­ver­sity, Eric Sar­gis (ed­i­tor), Yale Uni­ver­sity.

Ref­er­ences

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Flea­gle, J. 1999. Pri­mate Adap­ta­tion and Evo­lu­tion. San Diego: Aca­d­e­mic Press; An Im­print of El­se­vier.

Grueter, C., C. Van Schaik. 2009. Sex­ual Size Di­mor­phism in Asian Colobines Re­vis­ited. Amer­i­can Jour­nal of Pri­ma­tol­ogy, Vol­ume 71, Issue 7: 609-616. Ac­cessed April 23, 2013 at http://​onlinelibrary.​wiley.​com/​doi/​10.​1002/​ajp.​20695/​abstract.

Hor­wich, R. 1972. Home Range and Food Habits of the Nil­giri Lan­gur, Pres­bytis johnii. Jour­nal of the Bom­bay Nat­ural His­tory So­ci­ety, Vol­ume 69, Issue 2: 255-267. Ac­cessed April 06, 2013 at https://​docs.​google.​com/​viewer?​a=v&​q=cache:​4czjuOlrqTEJ:​www.​communityconservation.​org/​publications/​jbnhs69.​2..​pdf+Presbytis+johnii&​hl=en&​gl=us&​pid=bl&​srcid=ADGEESjbZUp-U6S8ISn6YU2jbcx340kuQ3WYMCPJWuyP4oGOX1-unBo-hl1qCZYLBsFk1tcaYDoUittWxqeLzPTIlsSZFQI4FnsacDtnf6Y270HuL1iXJvWI9ijLORviYz3V8w3SlUbn&​sig=AHIEtbQK4SakPGiB_​lxSRWT7HPgAesiTkw.

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Malviya, M., A. Sri­vas­tav, P. Nigam, P. Tyagi. 2011. "Na­tional Stud­book of Nil­giri Lan­gur (Tra­chyp­ithe­cus johnii)" (On-line pdf). Ac­cessed April 05, 2013 at http://​www.​cza.​nic.​in/​Nilgiri%20Langur%20studbook.​pdf.

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