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.
In zoology, a folivore is a herbivore that specializes in eating leaves. Mature leaves contain a high proportion of hard-to-digest cellulose, less energy than other types of foods, and often toxic compounds. For this reason, folivorous animals tend to have long digestive tracts and slow metabolisms. Many enlist the help of symbiotic bacteria to release the nutrients in their diet. Additionally, as has been observed in folivorous primates, they exhibit a strong preference for immature leaves which tend to be easier to masticate, are higher in energy and protein, and lower in fibre and poisons than more mature fibrous leaves.
Trachypithecus is a genus of Old World monkeys containing species known as lutungs, langurs, or leaf monkeys. Their range is much of Southeast Asia.
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.
Phayre's leaf monkey, also known as Phayre's langur, is a species of Old World monkey native to South Asia and Southeast Asia, namely India, Bangladesh, and Myanmar. Populations from further east are now thought to belong to other species. It is listed as Endangered on the IUCN Red List and is threatened by hunting and loss of habitat. The species epithet commemorates Arthur Purves Phayre.
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 maroon langur, maroon leaf monkey, or red leaf monkey is a member of the family Cercopithecidae. It is found on the southeast Asian island of Borneo and the nearby smaller Karimata. P. rubicunda mostly live in forests at altitudes below 2,000 m. They feed on leaves, seeds, and fruits.
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 Sarawak surili, Bornean banded langur, or cross-marked langur is a species of primate in the family Cercopithecidae. It is endemic to the southeast Asian island of Borneo, where it is distributed north of the Kapuas River in Kalimantan, Indonesia, the Malaysia states of Sarawak and Sabah, and in Brunei. Its taxonomy is complex and disputed, and it has been considered a subspecies of P. femoralis or P. melalophos. The Sarawak surili was formerly considered common, but has declined drastically due to persecution and habitat loss, and as of 2015 is only known from five sites with a combined population of 200–500 individuals. Consequently, it is believed to be one of the rarest primates in the world, and has been rated as critically endangered by IUCN.
The tufted gray langur, also known as Madras gray langur, and Coromandel sacred langur, is an Old World monkey, one of the species of langurs. This, like other gray langurs, is mainly a leaf-eating monkey. It is found in southeast India and Sri Lanka. It is one of three Semnopithecus species named after characters from The Iliad, S. hector and S. ajax being the others. In Sinhala it is known as හැලි වදුරා.
The western purple-faced langur, also known as the north lowland wetzone purple-faced langur, is a subspecies of purple-faced langur endemic to Sri Lanka. It lives in the wet zone in western Sri Lanka around the former capital city of Colombo. This subspecies are known to live in tropical rainforest, specifically in an area of Sri Lanka, where it is noted to rain two times more compared to the neighboring region. The subspecies is generally gray-brown with lighter whiskers, a gray rump patch, and dark forearms and legs. These monkeys also have dark brown or black, hairless faces. Their hands and feet are also hairless. When infants, their fur is medium brown to light gray, however it changes to their darker adult colors at between 12 and 16 weeks old. Typical length is between 48 and 67 centimetres excluding tail, with a 59 to 85 centimetres tail. On average, males weigh 8.5 kilograms (19 lb) and females weigh 7.8 kilograms (17 lb). Their average life span is about 26 years if the monkey was held in captivity. Due to their leafy diet, the western purple-faced langur back teeth, include high crowns and pointed cusps to make eating through greenery simpler. They also developed a digestive system that would allow them to break down cellulose in the leaves they eat. Although, leaves are their primary source of food, they also eat fruits and flowers. Female langurs hold a pregnancy for 195–210 days, and after the birth the offsprings are taken closely cared for by the mother until they are about 12–20 weeks old.
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 Siberut langur is a species of monkey in the family Cercopithecidae. It was formerly considered a subspecies of the Mentawai langur, Presbytis potenziani but genetic analysis revealed that these are separate species. The Siberut langur is native to the island of Siberut in Indonesia. It is listed as endangered by the IUCN.
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.
Miller's langur, also known as Miller's grizzled langur or Kutai grey langur, is a species of leaf monkey. It is endemic to East Kalimantan on the island of Borneo in Indonesia. It is one of the world's most endangered primates, and was at one time thought to be extinct, until it was rediscovered in 2012.
