Pygathrix nemaeus (Linnaeus, 1771)
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publication ID |
https://doi.org/ 10.5281/zenodo.6867065 |
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https://doi.org/10.5281/zenodo.6863414 |
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persistent identifier |
https://treatment.plazi.org/id/CE199B17-FFA0-FFA5-FF21-64BEF596F9CD |
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Jonas |
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Pygathrix nemaeus |
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122. View Plate 49: Cercopithecidae
Red-shanked Douc
French: Douc a pattes rousses / German: Rotschenkel-Kleideraffe / Spanish: Duc de patas rojas
Other common names: Red-shanked Douc Langur, Red-shanked Douc Monkey
Taxonomy. Simia nemaeus Linnaeus, 1771 ,
Vietnam, “Cochin-China.”
There is a small area of sympatry between P. nemaeus and P. cinerea in northern Quang Nam Province, Vietnam, and in north-eastern Cambodia (Virachey National Park), with some hybridization. Monotypic.
Distribution. EC & SE Laos, N & C Vietnam (but very fragmented), and a small area in NE Cambodia (Voensei, Ratanakkiri Province). Old records from Hainan I appear to be erroneous. View Figure
Descriptive notes. Head-body 55-63 cm (males) and 49-57 cm (females), tail 52— 66 cm (males) and 42-59 cm (females); weight 811-6 kg (males) and 6-8 kg (females). Coloration of the Red-shanked Douc is variable. Males and females are the same and have the typical features found in the species of Pygathrix . Back, crown, and upper arms are dark gray-agouti. Chest, belly, and throat are very pale whitish-gray. Below the white throat, a broad orange collar is bordered by a black line underneath that joins black parts on shoulders. Back of hands and forearms, nearly to elbows, are white; hands and feet are black. Upper legs are black, lower legs are chestnut from knees to ankles, and maroon hairs cover feet. Face is surrounded by white whiskers as long as 12 cm in adult males. A wide forehead band is black. Above base of tail is a triangular patch of white fur , which in males is further adorned by a pair of tufts at each anterior angle. Facial skin is orange to yellow-brown, except around mouth and chin, where it is white. Tail is white and has a thin tassel. Penis is pink, and scrotum is white. In a small area in north-eastern Cambodia and in the southernmost part of Laos, coloration of the Red-shanked Douc resembles that of the Gray-shanked Doucs ( P. cinerea ). White color on forearms is highly variable and in some individuals is reduced to small patches on wrists or completely missing. Forearms are gray-agouti. Maroon color on lower legs is also reduced to a reddish shine on gray-agouti legs. Natal coloration of the Red-shanked Douc is characterized by a light gray-agouti stripe on the back along the spine and white on the belly that extends over sides of the body to the back and to arms. Legs are light chestnut. From the forehead up to the crown, hairs are light chestnut; back of head is gray-agouti. Tail is whitish to grayish-white and has a thin tassel. There is a considerable variation in facial coloration, from a complete dark slate-gray face to more or less extended yellow patches under and over eyes, and to wider yellow eye-rings with only restricted gray parts around mouth, nose, and forehead. During the first five months oflife, forearms change to white, upper legs change to dark gray, and lower legs change to darker maroon. Chestnut color on head changes to gray, with a darker gray or blackish band over the forehead. Tail color changes to white. Slategray parts on face become paler over a long period of time, c.3 years, changing to the yellow-orange facial skin of adults.
Habitat. Subtropical and tropical evergreen or semi-deciduous broadleaf forest, (classified as lowland and montane forest), karst formations, and occasionally mixed bamboo forest. Red-shanked Doucs are observed from sea level up to an elevation of 1600 m. They prefer high forest canopies but occasionally go to the ground for water or to eat minerals.
Food and Feeding. The Red-shanked Douc is largely folivorous but also eats fruits and seeds. Its diet consists of ¢.80% leaves. Stomachs of 13 individuals contained 63% leaves and buds, along with flowers, fruits, and seeds. In Vietnam, 125 species of plants have been identified in the diet. Leaves are eaten from 83 species, fruits from 79, bark from five, and roots from one species. Young leaves that are high in crude protein and low in fiber are preferred. On average, leaf intake per individual is 1700 g/day.
Breeding. Male Red-shanked Doucs reach sexual maturity at 5-6 years old and females at 3-5-5 years. Females have 28-30day reproductive cycles, and their normally white genital area becomes suffused with red when sexually receptive and during pregnancy. A single young is born after a gestation of 180-190 days. Young are weaned at 9-16 months old, varying depending on whether or not the female has a new pregnancy. Interbirth intervals are 9-26 months. Infants are gray and ginger, with a mostly black face (mottled with pale pink). Allomothering appears to be common. Individuals have lived up to 25 years in captivity.
Activity patterns. Red-shanked Doucs are diurnal and arboreal. There are feeding peaks in the morning and afternoon, with a long rest at midday. They spend ¢.44% of their day feeding (30% on leaves and 14% on fruits), 15% engaging in social activities including grooming and playing, 14% inactive, 12% resting, 10% traveling, and 5% engaging in other activities. The time budget of daily activities varies among groups with and without human disturbance. A disturbed group rests less (c.5% less) and travels more. Leaping and jumping are the most common form of locomotion; brachiating may also be used when traveling in the forest canopy, particularly if individuals are fleeing or immediately before they begin leaping. Arboreal quadrupedalism is another mode of travel, which is often used where trees have open branches.
Movements, Home range and Social organization. Group structure of the Red-shanked Douc is either unimale—multifemale or multimale—multifemale, with 3-20 individuals/group (5-10 most common). The male-female ratio averages 1:2-4. Group composition estimated from several populations is 21% adult males, 51% adult females, 18% subadults, and 10% infants. Several groups sometimes travel and forage together for a while, forming bands of 50 or more individuals. A low-pitched growl is given as a threat, and there is also a short, harsh distress squeal. There is a specific “play face,” in which eyes are closed (exposing very blue eyelids). The characteristic fixed stare is actually a threat display, with an open-mouthed grimace being the corresponding gesture of submission, which is also used to initiate grooming. There is a pre-mating sexual signal given by both sexes, which consists of placing the jaw forward, raising eyebrows and then lowering them, and then shaking the head.
Status and Conservation. CITES Appendix I. Classified as Endangered on The IUCN Red List. The Red-shanked Douc is protected in all the three countries where it occurs. The population in Laos is probably quite large and is, as such, the most important for Red-shanked Doucs. The largest populations occur in Nakai-Nam Theun and Hin Namno national biodiversity conservation areas. In Vietnam, it has declined significantly in recent decades because of hunting, logging, and the conversion ofits forests for coffee, rubber, and cashew plantations. Hunting is the major threat to Redshanked Douc, most often for subsistence and traditional Asian medicine. The population is highly fragmented. The largest population in Vietnam exists most probably in Phong Nha-Ke Bang National Park, with an estimated 1300 individuals. Smaller populations in Vietnam exist in Pu Mat Nature Reserve and Bach Ma National Park (Nghe An and Thua Thien Hue provinces) and Son Tra Nature Reserve (Danang Province).
Bibliography. Ademmer (2002, 2003), Brockman (1976), Brockman & Lippold (1975), Byron & Covert (2004), Covert et al. (2004), Duckworth et al. (1999), Fooden (1996), Groves (2001), Haus (2008), Hick (1972), Jablonski (1995), Kavanagh (1972), Klumpe (2001), Kulcharoen & Utara (2010), Liedigk et al. (2012), Lippold (1977, 1981, 1998), Lippold & Vu Ngoc Thanh (1995, 2008), Mey (2010), Nadler & Streicher (2004), Nadler, Momberg et al. (2003), Nadler, Vu Ngoc Thanh & Streicher (2007), O'Brien (2006), Otto (2005), Pham Nhat (1993, 2002), Pham Nhat et al. (2000), Phiapalath & Suwanwaree (2010), Rawson & Roos (2008), Roos (2004), Roos & Nadler (2001), Roos et al. (2007), Ruempler (1998), Timmins & Duckworth (1999), Ulibarri (2006), Yeong et al. (2010).
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