The East Javan langur (''Trachypithecus auratus''), also known as the ebony lutung, Javan langur or Javan lutung, is an

Old World monkey Old World monkeys are primates in the family Cercopithecidae (). Twenty-four genera and 138 species are recognized, making it the largest primate family. Old World monkey genera include baboons (genus '' Papio''), red colobus (genus '' Piliocolob ...

from the

Colobinae The Colobinae or leaf-eating monkeys are a family (biology), subfamily of the Old World monkey family that includes 61 species in 11 genus, genera, including the black-and-white colobus, the large-nosed proboscis monkey, and the gray langurs. So ...

subfamily. It is most commonly glossy black with a brownish tinge to its legs, sides, and "

sideburns Sideburns, sideboards, or side whiskers are facial hair grown on the sides of the face, extending from the hairline to run parallel to or beyond the ears. The term ''sideburns'' is a 19th-century corruption of the original ''burnsides'', named ...

". It is found on the island of

Java Java is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea (a part of Pacific Ocean) to the north. With a population of 156.9 million people (including Madura) in mid 2024, proje ...

, as well as on several of the surrounding

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

n islands. The

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

word ''auratus'' in its

scientific name In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

means "golden" and refers to a less common color variant. The common name

golden langur Gee's golden langur (''Trachypithecus geei''), also known as simply the golden langur, is an Old World monkey found in a small region of Western Assam, India and the neighboring foothills of the Black Mountains of Bhutan. Long considered sacre ...

refers to a different species.

Description

Like all

langur The Colobinae or leaf-eating monkeys are a subfamily of the Old World monkey family that includes 61 species in 11 genera, including the black-and-white colobus, the large-nosed proboscis monkey, and the gray langurs. Some classifications split ...

s, this species' tail is noticeably long, measuring up to 98 cm in length while the body is only around 55 cm long. The two subspecies of this monkey are fairly similar in appearance and are geographically separated; males and females are both usually glossy black, although the females pale, yellowish-white patch around the pubic area. Juveniles of both subspecies are orange in color. The nominate subspecies ''Trachypithecus auratus auratus'' has a rare morph that does not lose its juvenile coloration when it matures, instead, the coloration darkens slightly, with yellow tinges on its sides, limbs, and around its ears, and a black tinge on its back.

Habitat

The East Javan langur inhabits the interior and peripheral areas of rainforests. This

primate Primates is an order (biology), order of mammals, which is further divided into the Strepsirrhini, strepsirrhines, which include lemurs, galagos, and Lorisidae, lorisids; and the Haplorhini, haplorhines, which include Tarsiiformes, tarsiers a ...

is diurnal and

arboreal Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally (scansorial), but others are exclusively arboreal. The hab ...

. Its diet is primarily

herbivorous A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat n ...

, eating leaves, fruit, flowers, and flower buds, although it also eats insect larvae. As with other

colobine The Colobinae or leaf-eating monkeys are a subfamily of the Old World monkey family that includes 61 species in 11 genera, including the black-and-white colobus, the large-nosed proboscis monkey, and the gray langurs. Some classifications split ...

s, it has evolved a specialised stomach to digest plant material more efficiently. This species also has enlarged

salivary gland The salivary glands in many vertebrates including mammals are exocrine glands that produce saliva through a system of ducts. Humans have three paired major salivary glands ( parotid, submandibular, and sublingual), as well as hundreds of min ...

s to assist it in breaking down food.

Behavior

Like other

s, the East Javan langur is a

social animal Sociality is the degree to which individuals in an animal population tend to associate in social groups (gregariousness) and form cooperative societies. Sociality is a survival response to evolutionary pressures. For example, when a mother was ...

, living in groups of around seven individuals, with one or two adult males in the group. Although they will look after offspring of other mothers as well as their own, adult females are aggressive towards females from other groups. The brighter coloring of juveniles may alert females to their presence and ensure that they will always be noticed and protected. This species has no discernible mating season and females produce one offspring at a time.

Subspecies

Formerly there were two subspecies of ''Trachypithecus auratus'' recognized: * Eastern Javan langur or spangled ebony lutung, ''Trachypithecus auratus auratus'' * Western Javan langur, ''Trachypithecus auratus mauritius'' Roos et al., 2008, elevated ''T. a. mauritius'' to a separate species as ''

Trachypithecus mauritius The West Javan langur (''Trachypithecus mauritius'') is an Old World monkey from the Colobinae subfamily. It was formerly considered a subspecies of '' Trachypithecus auratus'' until it was elevated to a separate species by Roos and Groves in 200 ...

''.

Gallery

Image:javan.langur.arp.jpg, Javan lutung ''Trachypithecus auratus auratus'' (light morph) in Bristol zoo Image:JavanLangur0906.jpg, Javan lutung ''Trachypithecus auratus auratus'' (light morph) Twycross Zoo, August 2006 Image:Javan langur.jpg, Twycross zoo Image:Image-Lutung Group 02 Zoo Hannover Germany.JPG, Group, Zoo Hannover, Germany Image:Ebony Langur Javan Lutung Trachypithecus auratus at Bronx Zoo 1 cropped.jpg,

Bronx Zoo The Bronx Zoo (also historically the Bronx Zoological Park and the Bronx Zoological Gardens) is a zoo within Bronx Park in the Bronx, New York City. It is one of the largest zoos in the United States by area and the largest Metropolis, metropol ...

References

{{Taxonbar, from=Q425601

East Javan langur The East Javan langur (''Trachypithecus auratus''), also known as the ebony lutung, Javan langur or Javan lutung, is an Old World monkey from the Colobinae subfamily. It is most commonly glossy black with a brownish tinge to its legs, sides, and ...

Primates of Indonesia Endemic fauna of Indonesia Fauna of Java Mammals of Indonesia Vulnerable fauna of Asia

Taxa named by Étienne Geoffroy Saint-Hilaire