Douc Langur, Pygathrix nemaeus June 2003

Fact Summary Taxonomy and Nomenclature Distribution and Habitat Physical Characteristics Behavior and Ecology Diet and Feeding Reproduction and Development Diseases and Pathology Population and Conservation Status Managed Care Other Web Resources Bibliography

Kingdom: Animalia
   Phylum: Chordata
       Class: Mammalia 
            Order: Primates
                  Parvorder: Anthropoidea
                        Family: Cercopithecidae (Old World Monkeys)
                              Subfamily: Colobinae (Leaf-eating Monkeys)
                                    Genus: Pygathrix
                                          Species: Pygathrix nemaeus
                                               Subspecies: Pygathrix n. nemaeus (northern Vietnam, Laos)
                                                                        Pygathrix n. nigripes (southern Vietnam, Cambodia)
                                                                        Pygathrix n. cinereus (central Vietnam)

• Taxonomic History
  • E. Geoffroy 1812. Ann. Mus. Hist. Nat., Paris. XIX, 1812 p 90. Genus Pygathrix is created. Simia nemaeus renamed Pygathrix nemaeus
  • A. Milne-Edwards, 1871. Nouv. Archiv. Mus. Hist Nat., Paris, VI p 7. Pygathrix nigripes described as distinct species
  • Napier 1985 Catalogue of primates in the British Museum (Natural History) and elsewhere in the British Isles. Part III: Family Cercopithecidae, Subfamily Colobinae. Synonimizes P. moi (Kloss, 1926) and P. nemaeus nigripes
  • Nadler, Tilo, 1997 Der Zoologische Garten (Neue Folge) 67(4) pp 165-176 Pygathrix nemaeus cinereus described
• The two subfamilies of Cercopithecidae, the Cercopithecinae and Colobinae have distinctive morphological adaptations related to diet. Colobines have a specialized digestive tract and Cercopithecines have buccal pouches.
• In the subfamily Colobinae, the colobus monkeys are found in Africa while others are found in Asia
• From 4-8 genera of Asian colobines are recognized by different primatologists: Pygathrix (doucs), Rhinopithecus (snub-nosed monkeys), Nasalis (proboscis monkey), Simias (simakobu), Trachypithecus (langurs), Presbytis (leaf-monkeys) and Semnopithecus (Hanuman or gray langurs)
• Primate taxonomy remains under discussion. Three subspecies have been recognized. Elevation to species status for all three subspecies has been suggested.
• Two subspecies of doucs have been acknowledged for some time, the third subspecies was proposed by Nadler in 1997

• Common name:  Douc Langur
• Pygathrix nemaeus comes from the Greek words "puge" meaning rump or buttocks and "thrix" the term for hair, denoting the long rump hair. "Nemus" is Latin for grove or forest.
• The Hindi name Langur or Lungoor pertains specifically to the common Sacred Monkey of Bengal, Semnopithecus entellus, but the name now includes more than 35 related species. A better name for this group would be "leaf-eating monkeys"
• Douc (pronounced "duke") is a French Cochin-china name
• German name: Kleideraffe or clothes monkey
• Viet Namese name: Vooc va
• "nigripes" refers to black shank color, "cinereus" refers to grey shank color

• Mitochondrial analysis by Zhang and Ryder suggest that the African Colobus diverged first among the colobines
• The fossil record indicates that current colobines probably originated in Africa and then migrated to Asia in the late Miocene
• Doucs and snub-nosed monkeys are recognized in the Pleistocene fossil record
• The doucs appear to be more closely related to the proboscis monkey (Nasalis) than to the snub-nosed monkeys (Rhinopithecus)
• The separation of the Pygathrix-Mesopithecus and Nasalis clades probably occurred in northern southeast Asia very soon after the splitting off of the snub-nosed monkeys
• Pygathrix nemaeus has a diploid number of 2n=44. Generally, the karyotypes of cercopithecine species tend to be similar to one another.

• Thirteen primate species inhabit Vietnam. Seven are endangered. Pygathrix nemaeus one of the most endangered.
• The red-shanked Douc langur (P.n. nemaeus) is one of five colobine monkey species found only in Vietnam and Laos. The distribution of the Douc langur is from Nghe An Province in the north to Tay Ninh Province in the south (500-1000m altitude). Little information about status in Laos but estimated in the thousands (Duckworth, personal communication to Nadler). These numbers are much higher than those for Vietnam.
• The black-shanked douc (P.n. nigripes) is found in southern Vietnam and Cambodia. The Da Lat/Di Linh Plateau in South Vietnam is the center of distribution.
• The grey-shanked douc (P.n.cinereus) is found in the southern part of the Annam Highlands (an area isolated from the other 2 subspecies)
• Subspecies occur together (are sympatric) throughout Vietnam's Central Highlands.
• Range Map (Lippold and Thanh, 1999) by Stephen Nash.

• Recent surveys have found them to be widespread and occupying a variety of habitats
• Multiple types of primary and secondary forest habitats: Semi evergreen hill forests, submontane evergreen forests, mixed deciduous forests, mixed evergreen podocarp forests, mosaics of primary evergreen forests, and closed broadleaved tropical forests.
• Medium and high altitudes.

• Modification of the growth pattern of nose cartilage to form a nasal flap
• Eyes almond-shaped and set at an angle. Color is dark brown, ringed in black
• Pygathrix nemaeus nemaeus (Red-shanked douc) (northern Vietnam and Laos)
  • Face pale yellow-orange with white muzzle (darkens with sun exposure). White whiskers are very long
  • Even-length coat. No cape
  • Sharply defined multi-colored coat.
  • Gray back and underparts. Upper part of legs is black as well as hands, feet, brow and shoulders
  • White tail, throat, sides of face, forearms and genital region
  • Prominent white rump patch. Males (unlike females) have circular white spot on either side and superior to the corners of the rump patch
  • Knee and below is rust-colored
  • Penis is red, scrotum white
  • Infants gray with black face and two pale stripes beneath eyes. Red tail patch
  • Tail ends in a thick tassel
• Pygathrix nemaeus nigripes (Black-shanked douc)(southern Vietnam and Cambodia)
  • Like the red-shanked but face is blue-gray with yellow-orange eye rings. Black wedge of color between ear and cheek. Shorter whiskers
  • Black area on forehead continues behind ears and onto shoulders
  • Hind limbs entirely black
  • Fore limbs and body gray, belly is paler gray. Hands are black
  • Scrotum and inside of thighs are blue
  • Penis is pink
  • White rump patch surrounds tail. Males (unlike females) have circular white spot on either side and superior to the corners of the rump patch. Tail ends in a thin tassel
• Pygathrix nemaeus cinereus (Grey-shanked douc) (south eastern part of Central Highlands)
  • Face coloration like red-shanked douc. Whiskers intermediate between P. nemaeus and P. nigripes
  • Lighter than the two other subspecies
  • Black band on forehead is narrower than other subspecies and not connected to the black shoulders
  • White throat has a thick band of orange.
  • Belly is light grey (lighter than P. nemaeus nigripes)
  • Scrotum is white, penis pink
  • Patch above root of tail and tail itself is white
  • White rump patch surrounds tail. Males (unlike females) have circular white spot on either side and superior to the corners of the rump patch. Tail ends in a thin tassel
• Known hybrids between P. n.nemaeus and P.n. nigripes have different coloration

• Diurnal and Arboreal. Never seen on the ground in the wild.
• In the wild, colobids spend at least 50% of the day feeding. In captivity they are offered food several times a day.
• There is considerable play within a family group. Animals of the same age tend to play together
• Social grooming in the wild occurs most frequently in the afternoon, before napping. Episodes last a few seconds to 1 hour
• Sleep in elevated positions; pairs sleep together and females sleep with their offspring

• Group size is variable depending on habitat and human disturbance. Sightings range from 3-50. Solitary animals have also been observed
• Groups are overwhelmingly multi-male and multi-female with a sex ratio of 2.5 females to each male.
• Both male and female dispersal occurs. Females probably leave as a result of female- female aggression. Juvenile males disperse and join all-male or non-reproductive groups of both sexes.
• Female association attributed to kinship and spatial distribution of preferred food resources. (Unripe Fruit/seeds)
• Colobine aggression increases with group size
• Alloparental care as with most Asian colobine species (gives mother time to forage, ensures social integration of new infants and improved parenting skills)
• Allogrooming somewhat more frequent than solitary auto grooming. Seen frequently among females. Males invited grooming but infrequently reciprocated.

• Group ranges overlap considerably
• Ability to exploit mature foliage which is available year round may explain why colobines appear to be less aggressive than non-colobines

• Considerable play in a family group. During first few months, infants engage in hopping, running, jumping and climbing.
• Usually directed at social partner or animal of same age
• To initiate play an animal throws back its head and opens its mouth

• Male observed to "threaten" intruders by brachiating back and forth. May leap toward an intruder. Then quickly retreat
• Rapid jumping from branch to branch combined with hand slapping
• Panic diarrhea common
• Threatening behavior toward others by males after the birth of a new born: flattening ears against the head, stretching the neck forward and making threatening growls

• Make few vocalizations. Most are very soft.
• Threat elicits a loud call or bark
• Low pitched growl given as a threat to others
• Loss of a long-time mate elicited several days of mournful howling in one male

• Quadrupedal movement though established arboreal pathways
• Little brachiation or bipedal locomotion
• Horizontal jumps begin like a dive, arms held above the head and legs thrust forward. Able to Land on rear feet 5-6 m away 
• Traveling:
  • Travel through the rainforest in single file.
  • Movement less organized in dense areas 

• Dominance hierarchies among captive groups
• Female-female allogrooming
• Intragroup relationships in wild poorly documented presumably because of poor visibility of arboreal species

• Folivore/frugivores. Unripe fruit and young leaves are less frequently available but preferred. Young leaves have less fiber and higher quantities of nutrients than mature leaves. Ripe fruit and its seed are usually not eaten. (Unripe fruit is lower in simple sugars. Ripe fruit can cause gastric distress)
• Not true ruminants, but large, morphologically complex 4-chambered stomachs requires lots of roughage.
• Process plant material from a wide variety of trees (Nhat documented 50 species) by fermentation. Plant cell walls are composed of cellulose that cannot be digested by vertebrates. Doucs maintain colonies of cellulolytic microorganisms (bacteria) in the Fore stomach which is used to ferment the polysaccharides making up cellulose
• Glands secrete enzymes into the lumen of the GI tract to digest proteins, lipids and simpler carbohydrates.
• Doucs are able to exploit mature foliage during food shortages (Nutritional value and protein of mature leaves are low, fiber is high).
• Up to 20% of the body weight may be eaten as foliage and the animals often appear to have bloated stomachs
• 82% of intake is leaves and petioles (at least 75% are young leaves), 14% is fruits and seeds (mainly unripe), 4% flowers,
• A recent study of food from five stomachs (Nhat) showed that (1) The quantity of food consumed every day varied from 450 grams to 650 (2) The diet consisted primarily of leaves, buds, fruit and flowers

• Most water comes from foods consumed.
• Observed to lick dew off leaves
• In zoos, water is consumed after dry food pellets are eaten. Doucs at the San Diego Zoo dip their nutritionally-enhanced biscuits in water before eating.

• Both males and females solicit copulation before and after ovulation.
• Female solicits copulation by intently staring at the male with mouth closed, chin thrust out. She moves her head from side to side. She then presents her Anogenital region and crouches down in front of him.
• Male responds with a vocal grunt. He then looks to a copulation site. The female moves to the site indicated and is followed by the male and copulation occurs.

• Female menstrual cycle is 28-30 days
• Cycling females exhibit a reddened inguinal/perineum area. If impregnated the area remains red throughout pregnancy. Color returns to white when estrogen level falls prior to delivery.
• During pregnancy females become increasingly calm and quiet; don't participate in social activities. Sit at the side of the enclosure close to a protective female
• Pregnant females exhibit care-taking behavior of all infants in the group until approximately 2 weeks before delivery when such behavior abruptly ceases (there may be a correlation with drop in estrogen level)
• Female becomes extremely restless just before birth, touching vagina and whipping tail back and forth
• Births occur year round; peak occurs between February and June
• Females from established groups often give birth in the same month, even same week
• In Cologne most births occur between 1900 and 2000 hours

• Birth weight: around 460 grams
• Eyes open at birth
• Natal coat - light chestnut with wide black stripe from shoulders to rump
• Black face. Eyes underlined with light stripes
• Clings to mother in first months - brief exploratory trips
• Day 7 - leaves mother
• Day 18 - takes food from other animals
• Day 60 - milk teeth fully developed. Leaves and fruit eaten in small quantities.

• Adult coat - Infant face black
• Male develops white spots on either side of rump patch
• Testicles descend. Scrotum fully developed. Brown penis becomes pink
• Weaning begun by 12-13 months. Still some non-nutritive suckling
• Greater independence from mother
• Solid food important
• Males spend time in rough play. Females spend time grooming

• Adult coat - infant face fades to color of adult
• Weaning tantrums frequent in both sexes

• Body size and facial color clearly distinguishable from infant.

• Puberty at 4-6 years in female, 4-9 years in male
• Lengthening of white hairs around face of male

• First successful captive births - June 1969 Memphis Zoo, August 1969 San Diego and May 1970 Cologne Zoo
• Interval between arrival of animal and reproduction has always been 2-4 years. Adults acquired as a group appear to acclimatize better and reproduce sooner than animals introduced from several sources
• Studbook Keeper: Lois Lippold

• Digestive problems have been the primary cause of mortality. Gastric distress (vomiting and diarrhea) Gastric amebiasis
• Phytobezoars formed by the long-fibred parts of plants or undigested Acacia leaves
• Abortions and stillbirths. Preclampsia, Placental chorioamnionitis.
• Cardiovascular disease (dissecting aortic aneurysm, aortic valvular thrombosis and heart failure and necrotizing myocarditis
• Glomerular disease
• Pneumonia
• Lung mites (Pneumonyssus simicola) resulting in pulmonary acariasis is now effectively treated
• Of the 28 offspring born in San Diego (1969-1998) 8 have died between 1.5-3.5 years. (Half of these were females who suddenly became weakened and lethargic) Data suggests that onset of puberty may be a sensitive time for females.

• In 1937 a Douc langur survived 4 months at the London Zoo
• Between 1967 and 1971 96 animals were imported into 20 collections. 7% were long term survivors.
• No wild-caught animals have been imported since 1981. (Marvin Jones)
• Beginning in the late ‘60s they were widely imported into US and European zoos. Exhibited in 8 zoos in 1968, 15 zoos by 1973. Currently successful colonies exist only in Cologne (2.8), San Diego (3.8) and Singapore (2.3)
• Difficult to maintain in captivity because of their highly specialized nutrition and habitat requirements. Gastric distress is the most common digestive disorder.
• Cologne offers only one kind of foliage at a time (leaves are removed from branches) When several different kinds are offered simultaneously, only the preferred leaves are eaten and the total amount consumed is lower. Diet augmented with vegetables, fruit and grains. No bananas, rice, bread, nuts or primate pellets
• San Diego provides an excess of browse (leaves are left on branches) Animals are also fed vegetables (broccoli, carrots, corn, cucumber, green beans, sweet potato, tomato, turnip and yam), leafy greens (collard, dandelion, mustard, bok choy, kale, romaine, and spinach). In addition, a specially formulated high-fiber biscuit is provided (Marion Zoological, Inc)
• Food is spread throughout the cage to avoid quarreling
• Temperature 77 degrees F and relative humidity 70% maintained at Cologne Zoo. Temperature is 80 at San Diego.
• Young animals are particularly susceptible to cold. Do not acclimatize well
• Must have sufficient shade - Doucs avoid direct sunlight
• Enclosures should be large enough to allow for jumping and running. Swinging elements, sitting perches, and play objects (use of natural fibers should be avoided because they may cause bezoars if ingested)
• Areas where animals can escape from visitor view desirable.
• Aggressive interactions-brief sparring without resultant injury. Low-pitched growl may be given as a threat
• May banish a single individual from the group
• Ruempler provides extensive data on hand-rearing

• USFWS Endangered
• IUCN Redlist of Threatened Species database.
  
• CITES Listed Species Database
• Estimated wild population (Primate Conservation Assessment Management Plan 1992)
  • Pygathrix nemaeus nigripes <2,500
• ISIS captive population

• Vietnam Government inaugurated first national park at Cuc Phuong in 1962
• In 1986 additional national parks and reserves were established. Currently there are 87 areas totaling approximately 3% of Vietnam
• A National Conservation Strategy was prepared in 1985 The National Plan for Environment and Sustainable Development was created in 1991
• At least 11 laws protect wildlife and CITES membership is in effect but law enforcement is weak, guards are underpaid, and punishments minimal (Without a set value on an endangered species it becomes impossible to set a fine for illegal hunting.)

• Vietnam has now lost over 80% of its historical forest cover. Only 10-20% of closed tropical forest remains.
• During the Vietnam War (1963-1975) over 72 million liters of herbicide were sprayed and approximately 22,000 sq acres of agricultural land and forests destroyed
• Rapid population growth. More than 70 million people in 1990 - 80% of the population practices subsistence agriculture. Remaining forests are subject to commercial logging, hunting and clearance.
• Government policy of relocating landless northerners to central highlands is decimating forests and wildlife
• Large-scale Logging operations in most of major forests
• Hunting for bush meat and medicinal purposes is a major activity. Many firearms in the country after years of warfare
• Illegal trade with China
• Subjects for taxidermy
• Protected wildlife is for sale in markets throughout the country
• Outside protected areas, remaining primate populations will become more fragmented

• Paul Massicot's Animal Info
• Primate Conservation in Vietnam
• Lois Lippold's Douc Langur Project
• International Directory of Primatology
• Langur information, WI Primate Research Center
• Illustrated identification guide, Endangered Primate Rescue Center

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