Trachypithecus pileatus (Blyth, 1843)

Russell A. Mittermeier, Anthony B. Rylands & Don E. Wilson, 2013, Cercopithecidae, Handbook of the Mammals of the World – Volume 3 Primates, Barcelona: Lynx Edicions, pp. 550-755 : 741-742

141.

Capped Langur

Trachypithecus pileatus

French: Langur a capuchon / German: Kappenlangur / Spanish: Langur encapuchado

Other common names: Bonneted Langur, Capped Leaf Monkey, Capped Monkey; Blond-bellied Capped Langur / Blond-bellied Langur (pileatus), Buff-bellied Capped Langur / Buff-bellied Langur (brahma), Orange-bellied Capped Langur / Orange-bellied Capped Leaf Monkey / Orange-bellied Langur (durga), Tenebrous Capped Langur / Tenebrous Capped Leaf Monkey (tenebricus)

Taxonomy. Semnopithecus pileatus Blyth, 1843 ,

type received from Barrackpore (menagerie), stated to be Malayan. Restricted by C. P. Groves in 2005 to India, Assam.

T. pileatus forms, together with T. shortridgei and T: geei , the pileatus species group. The phylogenetic position of this group remains unresolved, and the species might have evolved through hybridization of ancestors (3-4=7-1 million years ago) of today’s genera Trachypithecus and Semnopithecus . It is thought that seasonal variation in fur color may accountfor at least some of the subspecies recognized. More fieldwork is needed to verify their validity. The subspecies tenebricus hybridizes with 7. gee: in Bhutan. Four subspecies recognized.

Subspecies and Distribution.

1. p. pileatus Blyth, 1843 — NE India highlands S and E of the Brahmaputra River, in the states of Arunachal Pradesh, Assam, Meghalaya, and Nagaland (Karbi Anglong Plateau, Barail Range, and Khasi, Garo, Naga, and Jaintia Hills), and in NW Myanmar (W of the Chindwin River, S to Chin Hills Mts and Mt Victoria); the elevational range is 600-3000 m.

1. p. brahma Wroughton, 1916 — NE India, known only from the Dafla Hills, N of the Brahmaputra River, in Arunachal Pradesh State.

1: p. durga Wroughton, 1916 — E Bangladesh and NE India in the states of Assam, Mizoram, and Tripura (Naga Hills, Lakhimpur, Golaghat, Cachar Hills, Samaguting, and Sibsagar), adjoining the distribution of 7. p. pileatus to the N, but at lower elevations (i.e. from nearly sea level up to 600 m).

1. p. tenebricus Hinton, 1923 — NE India (Assam State) and Bhutan, in the Manas region N of the Brahmaputra River, with an elevational range of 100-2000 m.

Descriptive notes. Head-body 53-72 cm (males) and 47-66 cm (females), tail 83— 104 cm (males) and 72-102 cm (females); weight 11.5-14 kg (males) and 9.5-11.5 kg (females). The Capped Languris a large and highly variable form, noted forits short, upright crown hair. Coat is contrastingly colored, with a gray-to-brown dorsum and white-to-red underparts (belly often redder than chest and throat). Long, backwardswept cheek whiskers are buffy-white to red; crown cap is normally dark. External scrotum is absent. The “Blond-bellied Capped Langur” (1. p. pileatus ) is iron-gray to pale brown above, with a yellowy-gray-white belly. Its chest and throat are whitish tinged with buff, and cheek whiskers are buffy-whitish, sharply contrasting with dark tone of dorsum. Its upper arms and entire legs are lighter, and hands,feet, and tail-tip are dark. Its crown cap is like the dorsum. The “Orange-bellied Capped Langur” (7. p. durga) 1s pale slaty-gray above, with underparts (including inner surfaces of limbs), throat, and cheek whiskers orange to gingery, this tone extending further up flanks than in the Blond-bellied Capped Langur. Its head is not dark. The real existence of this subspecies is in question; its color tone perhaps merely the result of variations in temperature or humidity. The “Buff-bellied Capped Langur” (7. p. brahma) is less contrastingly colored than other subspecies, being generally dark gray above and becoming fawn-gray on lower flanks, rump, and legs. Its belly is white tinged with buff, chest and throat are white, and insides of limbs are pale gray. Its tail, hands, and feet are black. Its crown is not dark. The “Tenebrous Capped Langur” (7. p. tenebricus) is smaller and darker than the other subspecies, being generally ashy-black above, with a gray collar and legs. Belly is whitish in males and pale red in females, with remainder of underparts yellowish-orange. Its whiskers are grayish-yellow, and its black crown cap is defined behind a gray collar.

Habitat. Subtropical, broadleaf, evergreen, deciduous, submontane and bamboo forests and teak plantations. Depending on the region, the Capped Langur is sympatric with Phayre’s Langur (71. phayrei ) and the Nepal Sacred Langur ( Semnopithecus schistaceus ).

Food and Feeding. The Capped Langur is largely folivorous and eats young and mature leaves, supplemented with fruits, bark, seeds, flowers, and caterpillars. Gums and termite soil trails are also eaten on occasion. Water is obtained from tree cavities. The composition of the diet varies between seasons. Diets of the Orange-bellied Capped Langur have been studied at Madhupur in north-central Bangladesh. Leaves and leaf parts constituted 53% of their overall diet (based on feeding records), followed by seeds and fruit (34%), flowers (7%), and other items such as buds and bark (6%) and one caterpillar. Mature leaves accounted for 42% of the diet and young leaves 11%. Over a 15month study, 35 species of trees, lianas, and vines were identified as food sources. Twenty-two species provided leaves, eleven fruits, seven flowers, and six seeds. The mature leaf component of the diet varied from 5-1% in March-April when new leaves and fruits were abundant at the beginning of the monsoon to 65-1% in late winter in January-February when about two-thirds of the trees had lost their leaves. In May-September, fruits accounted for nearly 50% of the diet. Important species providing fruits were Ficus benghalensis and F. religiosa ( Moraceae ), Spondias mangifera ( Anacardiaceae ), and Terminalia bellirica ( Combretaceae ). Two species provided seeds, Mallotus philippensis (Euphorbiaceae) and Litsea polyantha ( Lauraceae ). At Pakhui Wildlife Sanctuary, the Tenebrous Capped Langur spent 67% ofits annual feeding time eating leaves: 57% young leaves, 6% mature leaves, and 4% petioles. They also ate fruits and seeds (16%) and flowers and buds (16%). Fifty-two plant species in 30 families were included in their diets. The most important species during the year were Gmelina arborea (Verbenacae; leaves), Albizia lucida ( Fabaceae ; leaves and fruits), Ficus glomerata ( Moraceae ; leaves), Mikania micrantha ( Asteraceae ; leaves), and Morus laevigata ( Moraceae ; leaves). Together, they accounted for nearly 60% of the feeding records. Most of their feeding (68%) was in the upper canopy. At Pakhui, they also fed, for some hours at a time, on water lilies.

Breeding. At Pakhui Wildlife Sanctuary in Arunachal Pradesh, the Tenebrous Capped Langur has two breeding seasons: September—January and April-May. At Madhupur, breeding occurs in October—February and later in April. At both sites, breeding occurred in the dry season. Females show proceptive behavior by head shaking, presenting their hindquarters to males, and raising an arm in a distinct fashion. This behavior sometimes leads to aggression, and males are aggressive to females or chase them before mating with them. Females give birth to a single young from late December through April; ¢.50% of births occur in February-March. The gestation period averages 200 days (196-205 days). The interbirth interval is c.2 years. Infants up to five months of age are creamy-white, with a golden tinge and pink skin. Allomothering takes place among adult females but is restricted to parous females; nulliparous females are rarely allowed to take infants. Allomothering is also restricted to particular female dyads; newborn infants are transferred to another female, but a single one during the first three months. This behavior is seen as altruistic, allowing lactating females to feed.

Activity patterns. Capped Langurs are diurnal and mainly arboreal. They occasionally feed and play on the ground. They feed early (06:00-10:00 h) and late (15:00-19:00 h) in the day, and rest at midday (11:00-15:00 h). Resting takes up 40% of their activity budget, feeding 35%, traveling 18%, and playing, grooming, and engaging in other activities 6:8%. Time spent feeding changes seasonally and is dependent on the contribution of fruit in the diet (which can be harvested more rapidly). In some months, feeding can be as low as 26% oftheir daily activities, and in others as high as 41%.

Movements, Home range and Social organization. Capped Langurs live in unimale— multifemale groups, with an average 7-5 individuals (range 2-14). All-male groups and solitary males are also observed. Home ranges vary among localities (c.21-64 ha). Daily movements are 320-800 m. Capped Langurs are territorial, and the adult male dedicates much of his day to vigilance. While a group rests, the male goes up into the canopy and calls and spreads his legs on either side of a branch to expose his lighter bare skin and give a penile display. Groups within 50 m of each other cause tension, and a male may chase his own group members away. Males display to each other by moving rapidly through trees and emitting a “hak” call. Agitated females scream and hug each other. A female group member approaching an opposing group might be chased and attacked by her group’s male; he will slap, bite, and pull at her if he catches her. Sometimes females transfer to other groups. Solitary males follow bisexual groups and try to gain access to the females. The resident male is less aggressive to males with whom he is familiar; he responds to the approach of unfamiliar males with more displaying than he does with familiar males. The pattern of male competition appears to involve successfully keeping females in the group, rather than aggressive confrontation with males. Golden Jackals (Canis aureus) will attack Capped Langurs when they are on the ground.

Status and Conservation. CITES Appendix I. Classified as Vulnerable on The IUCN Red List. The subspecies pileatus , durga, and tenebricus are classified as Endangered, and brahma as Data Deficient. Capped Langurs are nationally protected in all the countries where they occur. Itis the most common langur in north-eastern India, but habitat loss and hunting are major threats throughout its range. Habitat loss and fragmentation are caused mainly by expanding agriculture and timber and firewood collection; however, Capped Langurs are more adaptable to this situation than the sympatric Western Hoolock Gibbon (Hoolock hoolock). They are captured for the pet trade and widely hunted for their meat and body parts. The Orange-bellied Capped Langur is found in Madhupur National Park and Chunati, Kalenga and Rema wildlife sanctuaries in Bangladesh and Dampa Tiger Reserve, Murlen and Kaziranga national parks and Sepahijala, Trishna, Gumti Wildlife, Nengpui, Pabitora and Gibbon wildlife sanctuaries in India. The Tenebrous Capped Langur is found in Royal Manas National Park in Bhutan and Manas and Nameri national parks and Eagle Nest and Pakhui wildlife sanctuaries in India. The Blond-bellied Capped Langur is found in Namdapha, Balphakram, and Nokrek national parks and Siju Wildlife Sanctuary in India. A population estimate for the Capped Langur suggests less than 5600 mature individuals. For Blond-bellied and Orange-bellied capped langurs, fewer than 2500 mature individuals are estimated, with subpopulations having less than 250 mature individuals. The population of Tenebrous Capped Langurs is thought to be less than 600 mature individuals, and the Buff-bellied Capped Langur is only known from the holotype that was collected in 1911. Survey work to determine the population and conservation status is needed, particularly for the Buff-bellied Capped Langur.

Bibliography. Bennett & Davies (1994), Chetry et al. (2002/2003), Choudhury (1989, 2008b), Das et al. (2008), Green (1981), Groves (2005b), Islam & Husain (1982), Karanth (2008, 2010), Karanth et al. (2008), Kumar & Solanki (2004, 2008), Kumar, A. et al. (2005), Molur et al. (2003), Mukherjee (1978), Napier (1985), Osterholz et al. (2008), Solanki et al. (2007, 2008), Stanford (1988, 1989, 1991a, 1991b, 1991c, 1992).

Figures

140. Golden Langur (Trachypithecus gee), 141. Capped Langur (Trachypithecus pileatus), 142. Shortridge’s Langur (Trachypithecus shortridgei), 143. East Javan Langur (Trachypithecus auratus), 144. West Javan Langur (Trachypithecus mauritius), 145. Silvered Langur (Trachypithecus cristatus), 146. Selangor Silvery Langur (Trachypithecus selangorensis), 147. Germain’s Langur (Trachypithecus germaini), 148. Annamese Langur (Trachypithecus margarita)

Subspecies and Distribution. 1. p. pileatus Blyth, 1843 — NE India highlands S and E of the Brahmaputra River, in the states of Arunachal Pradesh, Assam, Meghalaya, and Nagaland (Karbi Anglong Plateau, Barail Range, and Khasi, Garo, Naga, and Jaintia Hills), and in NW Myanmar (W of the Chindwin River, S to Chin Hills Mts and Mt Victoria); the elevational range is 600-3000 m. 1. p. brahma Wroughton, 1916 — NE India, known only from the Dafla Hills, N of the Brahmaputra River, in Arunachal Pradesh State. 1: p. durga Wroughton, 1916 — E Bangladesh and NE India in the states of Assam, Mizoram, and Tripura (Naga Hills, Lakhimpur, Golaghat, Cachar Hills, Samaguting, and Sibsagar), adjoining the distribution of 7. p. pileatus to the N, but at lower elevations (i.e. from nearly sea level up to 600 m). 1. p. tenebricus Hinton, 1923 — NE India (Assam State) and Bhutan, in the Manas region N of the Brahmaputra River, with an elevational range of 100-2000 m.