Cross Marked Langur
The cross-marked langur is a leaf monkey found only on Borneo. It is also called the Bornean banded langur or Sarawak surili. The IUCN lists it as Critically Endangered. Its 2015 assessment put it in under 5% of its historic range.[1] Scientists call it one of the rarest primates in the world.
A Critically Endangered leaf monkey from the coastal lowland forests of western Borneo.
- Common NamesCross-marked Langur, Bornean Banded Langur, Sarawak Surili, Sarawak Langur
- Taxonomy Classification Year1838
- Monkey SizeHead and body 43 to 61 cm (17 to 24 in); tail 61 to 84 cm; weight 5.9 to 8.2 kg
- Skin Color(s)Jet black above with a pale whitish underside; the tricolored form is brown, red and white
- HabitatLowland rainforest, peat swamp forest and mangrove
- DietHerbivorous (leaves and fruit)
- Native CountriesMalaysia, Indonesia, Brunei
- The 2015 IUCN assessment estimated about 200 to 500 individuals.
- A 2024 action plan lists ten known or probable sites.
- Infants are born whitish gray with a dark back cross.
- Groups are small, usually one adult male with a few females.
- Half-day travel averaged only about 30 to 55 meters at Samunsam.
Cross-marked Langur Distribution
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Names and Taxonomy
Salomon Müller described this monkey in 1838 as Semnopithecus chrysomelas. The type locality is Pontianak in West Borneo.[2] For decades it was treated as a subspecies of other langurs. Older books listed it under Presbytis femoralis or Presbytis melalophos. Colin Groves later separated it as a full species on morphology.[3] Genetic work found it distinct from sampled femoralis and siamensis lineages. The same study left its species rank open.[4] The Mammal Diversity Database now lists it as a valid species.
Today it belongs to the Old World monkeys, family Cercopithecidae. It sits in the leaf-eating subfamily Colobinae. The genus Presbytis holds the surilis of Sundaland. The site covers the whole group under types of langurs.
Two subspecies are generally recognized. P. c. chrysomelas is the Bornean banded langur. P. c. cruciger is the tricolored langur.[5] Their validity and limits remain uncertain. One survey found the banded form where the tricolored form was expected. The IUCN says the subspecies ranges still need validation. An isolated population in southeastern Sarawak may be a third, undescribed form.
The name "cross-marked" comes from the infants. Newborns carry a dark cross along the back and shoulders. The epithet cruciger means "cross-bearer" for the same reason.
In Sarawak the monkey has many local names. Bidayuh speakers say penatat. Iban speakers say bijit. Kenyah speakers say berangad.[6]
Distribution and Range
The cross-marked langur belongs with the Borneo monkeys. Its historic range covered a wide arc of the island. It ran from northwestern Kalimantan through coastal Sarawak into Brunei and Sabah. Most of that mapped range is now historical.
The 2015 IUCN assessment knew the species from five sites. All five lie in Sarawak, home to many Malaysian monkeys. They are Maludam, Samunsam, Similajau, Tanjung Datu and the Lingga area. It may also persist in Betung Kerihun National Park, Kalimantan. See the other Indonesian monkeys for its neighbors there.
Later surveys have added sites. A 2024 action plan lists ten known or probable locations. Eight are in Sarawak and two in West Kalimantan. The Sarawak list adds Gunung Lesong, Gunung Pueh, Jemoreng and Lambir Hills.[7] Surveys in 2022 and 2023 confirmed the tricolored form at Jemoreng. Eight groups were seen there.[8]
In Indonesia the tricolored form lives around Danau Sentarum National Park. Local people call it the Sentarum langur.[9] Brunei is listed as a range country by the IUCN and ASAP.[10] No recent field record from Brunei turned up in the literature.
The species is primarily a lowland animal. The IUCN assessment placed it below 100 meters. Later records come from higher ground as well.
Habitat Preferences
It is one of the rainforest monkeys of the Bornean lowlands. The IUCN names swamp forest, lowland forest and mangrove as its habitats. At Samunsam, groups used riverine, mangrove, heath and dipterocarp forest. At Tanjung Datu, animals used dipterocarp forest and coastal beach forest.
Peat swamp forest is critical at sites such as Maludam and Jemoreng. Re:wild describes it as a monkey of Borneo's threatened peat swamps.[11] Other populations rely on dry lowland and coastal forest.
Appearance and Coat
The cross-marked langur is a medium-sized leaf monkey. Head and body measure 43 to 61 cm. The tail adds 61 to 84 cm. Adults weigh 5.9 to 8.2 kg.
The head carries a tall, narrow crest. A pair of small hair whorls sits near the brow. There is no clear fringe over the eyes.
The banded subspecies belongs among the black monkeys. The back is jet black, sometimes with a few brown hairs. The belly is pale whitish or fawn. That pale tone reaches the cheeks, chin, wrists and lower thighs. Field workers describe "striking black fur with a white underside".[12]
The tricolored subspecies looks very different. Its body is mainly brown, with a creamy underside. It counts among the brown monkeys of Borneo. A common "cross-bearing" morph keeps the infant cross pattern into adulthood. In that morph the legs, flanks and crown turn bright red.
Infants of both forms are born whitish gray. Compare them with Borneo's adult gray monkeys. A dark cross runs along the back and shoulders.
Diet and Feeding
The cross-marked langur is one of the herbivorous monkeys. The IUCN reports that it eats fruits and leaves.
Field studies give the balance. At Tanjung Datu in 2023, leaves made up about 81% of feeding. Fruit made up the other 19%. Food plants included Vatica pauciflora and Morinda citrifolia. A longer study did not measure seasonal diet in detail. Fruit availability may shape dry-season feeding.
One feeding habit was noted twice at Samunsam. At small fruit trees, only two or three animals fed together. The others waited in nearby trees for their turn.
Group Life
Groups are small. The IUCN gives a group size of three to seven. A typical group holds one male, up to three females, and young. At Tanjung Datu, three groups held seven, three and two animals. Each had a single adult male. Groups at Samunsam were larger, between 8 and 13.
At Danau Sentarum, eight groups held 58 animals. There was roughly one adult male per group. Adult females outnumbered adult males three to one.
Movement is slow and orderly. At Samunsam, the adult male led at the front or lowest point. Females with infants kept to the middle. Subadults brought up the rear. Travel was very short. Morning and afternoon paths each averaged about 30 to 55 meters.
Groups talk as they move. A low, short call was heard during horizontal travel. The group turned left or right in response. Vocalizing took 9% to 14% of the activity budget at Tanjung Datu.
Daily Activity
The cross-marked langur is diurnal and arboreal. Activity begins around 6 a.m. and ends near 7 p.m. In the wet season, groups start later and settle earlier.
Resting takes the largest share of the day, about 31% to 35%. Feeding and moving follow. Social activity increased during the dry season. Grooming occurred only then, but play occurred in both seasons.
The monkeys favor the canopy at 21 to 30 meters. When alarmed, they climb above 30 meters. They do come down. Animals were seen on the ground in beach forest at Tanjung Datu.
Threats and Decline
The cross-marked langur was once common. Naturalists reported it as common in the early 1900s. It has since disappeared from most of that range. A century of persecution and habitat loss followed. A 2013 handbook called it among the rarest primates on Earth.
Habitat conversion is the main threat. Oil palm plantations have taken much of the lowland forest. Shifting agriculture, pulp plantations and logging add to the loss. The 2015 assessment estimated an 80% fall over three generations. It put the remaining animals at about 200 to 500. New site records mean that estimate now needs reassessment.
Local pressures continue inside reserves. Poachers and illegal loggers enter Samunsam. A short 2023 survey at Tanjung Datu counted 13 animals. A 2003 survey had reported about 25. The 2023 authors call their count preliminary.
Conservation Status
The current IUCN assessment was completed in 2015 and published in 2020. It classed the species as Critically Endangered. It had been Data Deficient in 2000 and Critically Endangered since 2008. It is listed on CITES Appendix II.
Sarawak gives the monkey full legal protection. It is totally protected under the Wild Life Protection Ordinance 1998. Indonesian researchers report no species-level protection under national law. The Danau Sentarum population does live inside a national park.
It ranks among the world's 25 most endangered primates, 2023 to 2025. It is also an ASAP priority species. A 2024 to 2034 Asian langur action plan sets its priorities. These include surveys, taxonomic sampling, fire control and canopy bridges. The IUCN notes no captive population.
Related Langurs
Borneo holds several other Presbytis species. The maroon langur is the most widespread. The white-fronted langur lives across central Borneo. The north holds Hose's langur and the Saban grizzled langur. Miller's langur holds the east.
This species was long filed under the Malayan banded langur. Earlier authors placed it under the black-crested Sumatran langur. The Natuna Island surili is another Presbytis from nearby Natuna Island.
More Bornean and Asian species are listed under types of monkeys. This page also belongs to the monkeys starting with C index.
Cross-marked Langur FAQ
The cross-marked langur lives only on Borneo. Recent records come from Sarawak, Malaysia, and West Kalimantan, Indonesia. Brunei is listed as a range country.
Habitat loss, above all to oil palm, drove the cross-marked langur's decline. The 2015 IUCN assessment estimated an 80% decline over three generations. It put the population at about 200 to 500.
The cross-marked langur eats mostly leaves, with some fruit. One study measured about 81% leaves and 19% fruit.
Cross-marked langur infants are born whitish gray with a dark back cross. The subspecies name cruciger means cross-bearer.
The cross-marked langur measures 43 to 61 cm in head and body. The tail is 61 to 84 cm. Adults weigh about 6 to 8 kg.
The 2015 IUCN assessment estimated about 200 to 500 cross-marked langurs. Newer site records mean the figure needs updating.
Yes. Sarawak surili and Bornean banded langur both mean the cross-marked langur.
Cite this page
BioExplorer. (2026, November 2). Cross Marked Langur. https://www.bioexplorer.net/animals/mammals/monkeys/cross-marked-langur/
About the author
Wildlife Writer and Photographer, BioExplorer.net
Arjun is a science writer and wildlife photographer at BioExplorer.net. He turns new research on animals into clear, accurate reads for curious readers. His work covers animal behavior, ecology, and newly described species. He holds a Cornell Lab of Ornithology certificate in bird biology. He is pursuing an HBSc at the University of Toronto Mississauga.