Thomas's langur [1] | |
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Adult at the Bukit Lawang sanctuary. | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Primates |
Suborder: | Haplorhini |
Infraorder: | Simiiformes |
Family: | Cercopithecidae |
Genus: | Presbytis |
Species: | P. thomasi |
Binomial name | |
Presbytis thomasi (Collett, 1893) | |
Thomas's langur range |
Thomas's langur (Presbytis thomasi), also known as the North Sumatran leaf monkey or Thomas's leaf monkey, is a species of primate in the family Cercopithecidae. It is endemic to northern Sumatra, Indonesia, [3] not living to the south and east of Lake Toba and the Alas and Wampu rivers. [4] Its natural habitat is subtropical or tropical dry forests. It is threatened by habitat loss. [2] Its native names are reungkah in Acehnese and kedih in Alas. [5] It can be found in Gunung Leuser National Park, where substantial populations exist in Ketambe and Bukit Lawang. [3]
Although primarily folivorous, Thomas's langur also eats fruit, flowers, and occasionally toadstools and snails. Like other members of the genus Presbytis , this species has evolved to digest cellulose, and microbes in the gut extract nutrients from leaves. [6] Reflected in this diet of leaves is the extent to which they do consume fruit, which is usually unripe and with high pH levels to avoid killing the microbes they need to digest leaves. Thomas's langur also drinks from holes in trees where water collects or from small pools. [3] [6]
The hair on the top of the head rises in a crown, resembling a mohawk; this crown is white at the front with a dark grey stripe running down.[ citation needed ] Two tufts of fur extend on either side of its face.[ citation needed ] The belly is cream colored and the back of the animal is grey.[ citation needed ] It has amber eyes with grey outlines around the eyes.[ citation needed ] Juveniles have creamy white fur.[ citation needed ]
Thomas's langur is preyed upon by clouded leopards, Sumatran tigers, bay cats and reticulated pythons, which are particularly dangerous to this species when they[ clarification needed ] are on the ground. Thomas's langur disperses seeds and pollinates flowers of plants that they eat. [7]
Due to the ongoing deforestation of the Leuser and Ulu Massen Ecosystems in Northern Sumatra, Thomas's langur is threatened with extinction. It is protected by Indonesian Law under Cites Appendix II and as Vulnerable by the IUCN. [3] Although not as endangered as the charismatic megafauna it shares its habitat with, such as the critically endangered Sumatran orangutan and Sumatran elephant, the population of Thomas's langur has declined by thirty percent in the last few decades. As its habitat continues to erode due to human activity, it comes into conflict with people, moving into croplands where it becomes victim of the illegal pet trade and is seen as a pest by farmers, who cull them in large numbers with firearms. Like many other animals in SE Asia, Thomas's langur is also dismembered and its parts sold for medicine.
Although protected by Indonesian Law, Thomas's langur is becoming habituated to tourists who visit Gunung Leuser National Park. Though discouraged and prohibited, humans feed Thomas's langurs and other primates in the park causing negative consequences for wildlife and people. [6] Thomas's langur lives twenty years in the wild, but twenty nine years in captivity. It is possible the lack of stress and predators found in their environment is responsible for the extended lifespan in captivity. [7]
Semnopithecus is a genus of Old World monkeys native to the Indian subcontinent, with all species with the exception of two being commonly known as gray langurs. Traditionally only the species Semnopithecus entellus was recognized, but since about 2001 additional species have been recognized. The taxonomy has been in flux, but currently eight species are recognized.
Presbytis is a genus of Old World monkeys also known as langurs, leaf monkeys, or surilis. Members of the genus live in the Thai-Malay Peninsula, on Sumatra, Borneo, Java and smaller nearby islands.
The Sumatran orangutan is one of the three species of orangutans. Critically endangered, and found only in the north of the Indonesian island of Sumatra, it is rarer than the Bornean orangutan but more common than the recently identified Tapanuli orangutan, also found in Sumatra. Its common name is based on two separate local words, "orang" and "hutan" ("forest"), derived from Malay, and translates as 'person of the forest'.
The silvery lutung, also known as the silvered leaf monkey or the silvery langur, is an Old World monkey. It is arboreal, living in coastal, mangrove, and riverine forests in Peninsular Malaysia, Sumatra, Borneo, Java, and other nearby islands. It is the type species of its species group.
The Sumatran striped rabbit, also known as the Sumatra short-eared rabbit or Sumatran rabbit, is a rabbit found only in forests in the Barisan Mountains in western Sumatra, Indonesia, and surrounding areas. It is threatened by habitat loss.
The Tropical Rainforest Heritage of Sumatra site was inscribed as a UNESCO World Heritage Site in 2004. It comprises three Indonesian national parks on the island of Sumatra: Gunung Leuser National Park, Kerinci Seblat National Park and the Bukit Barisan Selatan National Park. The site is listed under Criteria vii - outstanding scenic beauty; ix- an outstanding example representing significant on-going ecological and biological processes; and x- contains the most important and significant natural habitats for in-situ conservation. The Tropical Rainforest Heritage of Sumatra has been placed on the Danger List since 2011 to help overcome threats posed by poaching, illegal logging, agricultural encroachment, and plans to build roads through the site.
The Javan surili is a vulnerable species of Old World monkey endemic to the western half of Java, Indonesia, a biodiversity hotspot. Other common names by which it is known by include gray, grizzled or Sunda Island surili; grizzled or stripe-crested langur; Javan grizzled langur; grizzled, Java or Javan leaf monkey; langur gris.
The Raffles' banded langur, also known as the banded leaf monkey or banded surili, is a species of primate in the family Cercopithecidae. It is endemic to Singapore and southern Peninsular Malaysia. The species underwent taxonomic revisions in 2019 and 2020, in which two former subspecies were elevated to separate species. As a result, the Raffles' banded langur meets the criteria for being listed as critically endangered by the IUCN. It is mainly threatened by habitat loss.
Hose's langur is a species of primate in the family Cercopithecidae endemic to the island of Borneo, including Brunei, Kalimantan (Indonesia), and East Malaysia. Its natural habitat is subtropical or tropical dry forests. It is threatened by habitat loss. It was first identified in Kutai National Park and Sangkulirang Peninsula, East Kalimantan, Indonesia, in 1985.
The black-crested Sumatran langur is a species of primate in the family Cercopithecidae. It is endemic to Sumatra in Indonesia. Its natural habitat is subtropical or tropical dry forests. It is threatened by habitat loss.
The Mentawai langur is a species of primate in the family Cercopithecidae. It is endemic to the Mentawai Islands in Indonesia. Its natural habitat is subtropical or tropical dry forests. The Siberut langur was formerly considered a subspecies of the Mentawai langur.
The white-thighed surili is a species of primate from the family of old world monkeys (Cercopithecidae). This species lives arboreal amongst the sub-montane forests. It is endemic to the Thai-Malay Peninsula, the Riau Archipelago and Sumatra. In addition, the white-thighed surili contain four subspecies: siamensis (nominate), cana, paenulata and rhionis, are recognized here. Furthermore, they are characterized by the white patches located on the outside of their legs, which is what gives them their name. Additionally, they can be referred to as pale-thighed langur/surili. These primates are an important species for the diversity of forest environments in the Malaysian area.
The dusky leaf monkey, also known as the spectacled langur or the spectacled leaf monkey, is a species of primate in the family Cercopithecidae. It is found in Peninsular Malaysia, Myanmar and Thailand, and can occasionally be found in Singapore. During the day, these small, folivorous primates divide in sub-groups and forage for vegetation and fruit throughout the tropical forests. According to the IUCN, the dusky leaf monkey's population is declining due to habitat loss, poaching, and anthropogenic land use, which prompted the IUCN to classify the species as endangered in 2015.
The East Sumatran banded langur, also known as the East Sumatran banded surili, is a species of monkey in the family Cercopithecidae. It was formerly considered a subspecies of the Raffles' banded langur Presbytis femoralis, but genetic analysis revealed it to be a separate species. Its range is restricted to the Riau Province of east-central Sumatra. Due to its declining population and restricted range in small, isolated forests subject to high rates of deforestation, the IUCN declared it to be a critically endangered species in 2020.
The mitered langur is a species of monkey in the family Cercopithecidae. It was formerly considered a subspecies of the Sumatran surili, Presbytis melalophos but genetic analysis revealed that these are separate species. The mitered langur is native to the island of Sumatra in Indonesia. It is listed as endangered by the IUCN due primarily to deforestation, and also due to animals taken for pets.
The black-and-white langur is a species of monkey in the family Cercopithecidae. It was formerly considered a subspecies of the Black-crested Sumatran langur, Presbytis melalophos but genetic analysis revealed that these are separate species.
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The Sabah grizzled langur, also known as the Saban grizzled langur, is a species of monkey in the family Cercopithecidae. It was formerly considered a subspecies of Hose's langur, Presbytis hosei. The Sabah grizzled langur is native to the island of Borneo in the province of Sabah in Malaysia, with part of its range in Indonesia. It is listed as endangered by the IUCN due primarily to habitat loss, fragmentation and hunting.
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