The Javan langur is a diurnal and arboreal primate (5). It feeds mainly on leaves, fruit, flowers, flower buds, and insect larvae and, like other members of the Colobinae subfamily, has evolved a specialised stomach to digest plant material more efficiently (3). This species also has enlarged salivary glands to assist it in breaking down food (5). This langur lives in social groups of around seven individuals, with one or two adult males in the group (5). Adult females are aggressive towards females from other groups, and have been observed looking after the offspring of other mothers, as well as their own. It is thought that juveniles are brightly coloured because this alerts females to their presence and ensures that they will always be noticed and protected (3) (5). Mating occurs throughout the year and females produce one offspring at a time (5).

The name 'langur' means 'long tail' in Hindi (4), and this species' tail is indeed noticeably long, measuring up to 87 cm in length while the body is only around 55 cm long (2) (3). There are two subspecies of the Javan langur: the eastern Javan or spangled ebony langur (Trachypithecus auratus auratus) has two distinct colourations: the more common one being glossy black in colour with a slight brownish tinge on the sides of the body, 'sideburns', and legs (5). The skin of the face, palms and soles is also black. The rarer form of this subspecies is a deep orange colour with yellow tinges on the side of the body, limbs and hair around the ears, and black tinges on the back (5). The second subspecies, the western Javan or West Javan ebony langur (Trachypithecus auratus mauritius) is glossy black with a very slight brownish tinge on the sides of the body, sideburns and legs (5). Female Javan langurs can be distinguished from males by the pale, yellowish white patch around the pubic area. Juveniles are even more distinctive as they are orange in colour (6).

This species is endemic to Indonesia, where it occurs on Java and the smaller islands of Bali, Lombok, Palau Sempu and Nusa Barung. The Lombok population may have been introduced there by humans (Groves 2001). The boundary between the two subspecies runs from the south coast of Java at about 109°E, northwestward to the vicinity of Jakarta (Groves 2001).

Trachypithecus auratus auratus
Occurs in eastern Java, Bali, Lombok, Palau Sempu and Nusa Barung. This subspecies has two morphs, one of which, the red morph, has a restricted distribution between Blitar, Ijen, and Pugeran, Java (Groves 2001). The other morph is more common and found in eastern Java, west to Gunung Ujungtebu (Brandon-Jones 1995).

Trachypithecus auratus mauritius
This subspecies has a restricted distribution in west Java to the north coast from Jakarta, inland to Bogor, Cisalak, and Jasinga, southwest to Ujung Kulon, then along the south coast to Cikaso or Ciwangi (Groves 2001).

Trachypithecus auratus, commonly known as the Javan langur, is isolated to Java, Bali, and the Indonesian island of Lombok. They can be found in both the inland forests of western Indonesia as well as the southern coastline.

Biogeographic Regions: oriental (Native )

Other Geographic Terms: island endemic

This species is found on the island of Java and the smaller islands of Bali and Lombok, Indonesia, though the subspecies are geographically separated (5). The subspecies Trachypithecus auratus auratus is found between Blitar, Ijen, Pugeran, eastern Java and Gunung Ujungtebu, while the subspecies Trachypithecus auratus mauritius has a restricted distribution from west Java to Jakarta, as well as inland in Bogor, Cisalak, Jasinga and Ujung Kulon, then along the south coast to Cikaso or Ciwangi (5).

Two subspecies of Javan langurs are described: western Javan langur (or western Javan ebony langur (Trachypithecus auratus mauritius) and eastern Javan langurs (or spangled ebony langurs, Trachypithecus auratus auratus). However, several genetic studies dispute the validity of T. auratus subspecies. Both subspecies have glossy black coats with brown on the legs and belly. Sometimes, individual T. auratus auratus have orange coats. Orange color morphs are found in a restricted portion of the distribution of eastern Javan langurs. Javan langur infants are born with orange coats and the coats get darker as they age. Female coloration is slightly different, they have yellow pubic patches. Javan langur mass is approximately 7 kg. Head and body length is from 44 to 65 cm and tail length is 61 to 87 cm. They move quadrupedally and have enlarged salivary glands and a dental formula of 2:1:2:3. Javan langurs also have sacculated stomachs that assist in breaking down plant materials.

Average mass: 7 kg.

Range length: 44 to 65 cm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: sexes colored or patterned differently

Habitat and Ecology

Systems

• Terrestrial

Trachypithecus auratus inhabits both the interior and edges of rainforests, and has been observed in both primary and secondary forests in the Dieng Mountains of central Java. Trachypithecus auratus has been observed in a variety of forest types: mangrove, beach, freshwater swamp, lowland and hill forest, deciduous forest, and mountain forest up to 3500 meters.

Range elevation: 0 to 3500 m.

Habitat Regions: tropical ; terrestrial

Terrestrial Biomes: forest ; rainforest ; mountains

Aquatic Biomes: coastal

Wetlands: swamp

Inhabits the interior and peripheral areas of rainforests (5).

Javan langurs eat mostly leaves and flowers. Their enlarged salivary glands and sacculated stomachs are well adapted for this plant diet. They also eat fruit, ripe and unripe, and insect larvae. The diet consists of 15 to 27% unripe fruit and 10 to 12% ripe fruit. They may eat fruits mainly to get at the seeds. Javan langurs prefer leaves rich in protein content and low in fiber. Different groups will feed at the same food source without significant aggression. Adult males do not proportionally feed as often as other group members, females and the young.

Animal Foods: insects

Plant Foods: leaves; seeds, grains, and nuts; fruit; flowers

Primary Diet: herbivore (Folivore , Frugivore )

Javan langurs impact forest vegetation through their diet, they eat leaves and may help to disperse seeds through their frugivory. No studies have been conducted on the parasites that infect Trachypithecus auratus.

Ecosystem Impact: disperses seeds

The only known predators of Javan langurs are humans. Humans illegally hunt them for food and the pet trade. Anti-predator adaptations of T. auratus include a shrill alarm call when a human is sighted. Likely natural predators include the now extinct, Javan tiger (Panthera tigris sondaica) and Javan leopards (Panthera pardus melas).

Known Predators:

• humans (Homo sapiens)
• Javan leopards (Panthera pardus melas)
• Javan tiger (Panthera tigris sondaica)

Javan langurs communicate acoustically. They use alarm calls that sound like "ghek-ghok-ghek-ghok." They also communicate through visual cues and touch. Infants are brightly colored and females will look after and protect infants of other females. It has been hypothesized that females behave in this manner because the bright orange color of the infants signals that they need to be cared for. Allogrooming is an important way to cement social bonds. Aggression is communicated with physical interactions, vocalizations, and visual cues, all of which establish social rank. Research on chemical communication by Trachypithecus auratus has been lacking.

Communication Channels: visual ; tactile ; acoustic

Perception Channels: visual ; acoustic

The lifespan of Trachypithecus auratus is approximately 20 years, like many other species of Old World monkeys.

Average lifespan

Status: wild: 20 years.

Maximum longevity: 31.1 years (captivity) Observations: A hybrid between a silvered and a Southern Java langur lived 31.2 years in captivity (Richard Weigl 2005).

Javan langurs have 1 to 2 males in each group, which has a large effect on the group's mating behavior. There is virtually no within-group competition among males, ensuring that they are successful in mating. Males in the group father all offspring. Females in social groups cooperate to care for all young in the group.

Mating System: polygynous ; cooperative breeder

Female Javan langurs typically begin to breed around 3 to 4 years of age, and give birth once a year, one offspring at a time. Breeding and births can occur throughout the year. The infants develop quickly and are often independent within their first year of life. Mothers in the group all care for each others' young, otherwise known as "allomothering." Other aspects of reproduction are not reported in the literature.

Breeding interval: Javan Langurs breed once yearly.

Breeding season: Javan langurs breed throughout the year.

Average number of offspring: 1.

Average time to independence: 12 months.

Range age at sexual or reproductive maturity (female): 3 to 4 years.

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

Females are the primary caregivers for the infants and are known to care for infants from other females within the group. The vibrant color of young Javan langurs may make it easier for mothers to keep track of their offspring, and to ensure that they are protected and cared for.

Parental Investment: precocial ; female parental care ; pre-independence (Provisioning: Female)

Year Assessed

Assessor/s

Reviewer/s

Justification

History

• 2000
  Endangered
• 1996
  Vulnerable

Javan langurs are listed as vulnerable on the IUCN Red List. Populations are decreasing due to human activities, such as habitat loss resulting from agricultural expansion, hunting, and the illegal pet trade. Laws protecting Trachypithecus auratus in Indonesia were passed in 1999. Javan langurs are found in 3 Indonesian national parks: Gunung Halimun, Pangandaran, and Ujung Kulon.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: vulnerable

Classified as Endangered (EN B1+2ab) on the IUCN Red List 2004 (1). Two subspecies are recognised: Trachypithecus auratus auratus is classified as Endangered (EN A1c, B1+2cd), and Trachypithecus auratus mauritius as Endangered (EN B1+2ab) on the IUCN Red List 2004 (1).

Population

Population Trend

Major Threats

This primate is threatened by the destruction of its habitat for timber and cultivation (1). In Indonesia there have been cases of local people deliberately setting fire to forest to clear it for agriculture, which has had devastating consequences for this arboreal monkey (3). Hunting is also a major threat in Indonesia, and the increased availability of firearms has made the problem worse (3).

Conservation Actions

The species is currently found in 3 protected areas – Gunung Halimun NP, Pangandaran NR and Ujung Kulon NP (2). In addition to protecting the remaining forest habitat, it is essential that more is done to stop hunting and the bush meat trade in this part of the world (7). Without human intervention and protection, the endangered Javan langur will face extinction in the future (3).

There are no studies that document decreased health of people or agricultural plants because of Trachypithecus auratus.

Javan langurs are important members of native ecosystems and may form the basis of ecotourism activities. Javan langurs are sometimes hunted for food or captured for trade, but these are illegal activities.

Positive Impacts: pet trade ; food