Raffles’ banded langur (Banded leaf monkey)


The Raffles’ banded langur (Presbytis femoralis femoralis) is black-and-white monkey native to Singapore. However, it is on the verge of extinction in Singapore with an estimated population of just 40 to 60 monkeys. In the 2008 edition of The Singapore Red Data Book, the banded leaf monkey was listed as “critically endangered’, when not more than 30 individuals were documented in Singapore during that time.1

Description
The Raffles’ banded langur is a subspecies of the genus Presbytis, from the primate family Cercopithecidae, also known as the “Old World monkeys”.2 They were first described as Semnopithecus femoralis by W.C.L. Martin in 1838, and although the species was originally thought to be from elsewhere, several researchers determined the type locality to be restricted to Singapore in 2014.3 There are also two other subspecies in this group: the East Sumatran banded langur (Presbytis femoralis purcura) and Robinson’s banded langur (Presbytis femoralis robinsoni).4 Singapore only has two native monkey species: the Long-tailed macaque (Macaca fascicularis)5 and Raffles’ banded langur.6

The Raffles’ banded langur can grow up to 59 cm long, or 84 cm inclusive of its tail,7 and can weigh up to 6 kg.8 Its alarm call is described as akin to the rattle of a machine gun.9

It has a round head, with forward-looking eyes and a short muzzle.10 A white line runs down the middle of its chest and belly, and the fur on the inner parts of its arms and legs until just below its knees is white.11 Each eye has a light-coloured ring encircling it and there is a pale crescent shape between the eye and ear on both sides of its face.12 It has long limbs and tail, a protruding abdomen and the fur on its head is directed towards the centre of its crown where it stands erect.13 Adult banded leaf monkeys have black fur, while the young generally have fur ranging from white to pale grey. Some infants with orange fur have been reported.14

An arboreal monkey, it inhabits high treetops in tropical rainforests and hardly ever comes to the ground. It is herbivorous and feeds mainly on the fruits and new leaves of selected trees. It is a gregarious animal, normally associating in groups and travelling together with fellow troop mates.15

Distribution
Up to the 1920s, the Raffles banded langur was reported in various parts of Singapore, including Changi, Tampines, Bukit Timah, Pandan and Tuas.16 Currently, it is found only in the Central Catchment Nature Reserve.17

In 1987, Raffles Museum of Biodiversity Research curator Lua Hoi Kheng witnessed, from the window of her house near Bukit Timah Hill, an elderly female banded leaf monkey descending a tree before being mauled to death by a pack of five dogs. It is believed to have been the last member of a tribe living in the Bukit Timah forest.18

Threats
Although these monkeys were once hunted for food, the main threat to their survival today is habitat loss.19 Deforestation has resulted in fewer habitats for these primates and they are now confined to the Bukit Timah Nature Reserve and Central Catchment Nature Reserve.20 However, the construction of the Bukit Timah Expressway in 1983 separated what was once a single forest that comprised both nature reserves. This effectively stopped all gene flow, limiting their genetic diversity, subsequently causing the banded leaf monkeys to disappear from the Bukit Timah Nature Reserve altogether.21 As of 2016, the estimated population of banded leaf monkeys stands at 40 to 60.22 Researchers have noted that Singapore has the lowest monkey population as compared to other similar leaf-eating monkey populations elsewhere in the world, besides also suffering from depleted genetic diversity.23 In 1990, only 10 to 15 individuals were estimated to remain at the Central Catchment Nature Reserve.24

Variant names
Scientific name: Presbytis femoralis femoralis (subspecies)25
Common names:
English: Raffles banded langur26, banded leaf monkey, Raffles’ surili27



References
1. Davison, G. W. H., Ng, P. K. L., & Ho, H. C. (Eds.). (2008). The Singapore red data book: Threatened plants & animals of Singapore (2nd ed.). Singapore: Nature Society (Singapore), p. 198. (Call no.: RSING 591.68095957 SIN)
2. Low, M. E. Y and Lim, K. K. P. (2015, October 30). The authorship and type locality of the banded leaf monkey, Presbytis femoralis. Nature in Singapore, 8, 69. Retrieved from https://lkcnhm.nus.edu.sg/nus/images/pdfs/nis/2015/2015nis069-071.pdf
3. Roos, C., et al. (2014). An updated taxonomy and conservation status review of Asian primates. Asian Primates Journal, 4(1), 10. Retrieved from http://www.primate-sg.org/asian_primates_journal/
4. Roos, C., et al. (2014). An updated taxonomy and conservation status review of Asian primates. Asian Primates Journal, 4(1), 10. Retrieved from http://www.primate-sg.org/asian_primates_journal/
5. Macaca fascicularis. (2008). The IUCN Red List of Threatened Species. Retrieved from http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T12551A3355536.en
6. Roos, C., et al. (2014). An updated taxonomy and conservation status review of Asian primates. Asian Primates Journal, 4(1), 10. Retrieved from http://www.primate-sg.org/asian_primates_journal/
7. Baker, N., et al. (2008). Wild animals of Singapore: A photographic guide to mammals, reptiles, amphibians and freshwater fishes. Singapore: Draco Publishing and Distribution; Nature Society (Singapore), p. 135. (Call no.: RSING 591.95957 WIL)
8. Ng, P. K. L., et al. (1995). A guide to the threatened animals of Singapore. Singapore: Singapore Science Centre, p. 140. (Call no.: RSING 591.529095957 GUI)
9. Call of the wild. (2008, April 5). The Straits Times, p. 71. Retrieved from NewspaperSG.
10. Baker, N., et al. (2008). Wild animals of Singapore: A photographic guide to mammals, reptiles, amphibians and freshwater fishes. Singapore: Draco Publishing and Distribution; Nature Society (Singapore), p. 135. (Call no.: RSING 591.95957 WIL)
11. Baker, N., et al. (2008). Wild animals of Singapore: A photographic guide to mammals, reptiles, amphibians and freshwater fishes. Singapore: Draco Publishing and Distribution; Nature Society (Singapore), p. 135. (Call no.: RSING 591.95957 WIL)
12. Baker, N., et al. (2008). Wild animals of Singapore: A photographic guide to mammals, reptiles, amphibians and freshwater fishes. Singapore: Draco Publishing and Distribution; Nature Society (Singapore), p. 135. (Call no.: RSING 591.95957 WIL)
13. Baker, N., et al. (2008). Wild animals of Singapore: A photographic guide to mammals, reptiles, amphibians and freshwater fishes. Singapore: Draco Publishing and Distribution; Nature Society (Singapore), p. 135. (Call no.: RSING 591.95957 WIL)
14. Baker, N., et al. (2008). Wild animals of Singapore: A photographic guide to mammals, reptiles, amphibians and freshwater fishes. Singapore: Draco Publishing and Distribution; Nature Society (Singapore), p. 135. (Call no.: RSING 591.95957 WIL)
15. Baker, N., et al. (2008). Wild animals of Singapore: A photographic guide to mammals, reptiles, amphibians and freshwater fishes. Singapore: Draco Publishing and Distribution; Nature Society (Singapore), p. 135. (Call no.: RSING 591.95957 WIL)
16. Ng, P. K. L., et al. (1995). A guide to the threatened animals of Singapore. Singapore: Singapore Science Centre, p. 140. (Call no.: RSING 591.529095957 GUI)
17. Ang, A. (2016). The plight of the Asian Colobines: Profiling Singapore’s banded leaf monkey and Vietnam’s Tonkin snub-nosed monkey. Asian Geographic, 1(116), 43.
18. Chang, A-L. (2002, April 8). Going... Going... Gone? The Straits Times, p. 1. Retrieved from NewspaperSG.
19. Ng, P. K. L., et al. (1995). A guide to the threatened animals of Singapore. Singapore: Singapore Science Centre, p. 140. (Call no.: RSING 591.529095957 GUI)
20. Ang, A., et al. (2012). Low genetic variability in the recovering urban banded leaf monkey population of Singapore. The Raffles Bulletin of Zoology, 60(2), 590. Retrieved from http://lkcnhm.nus.edu.sg/rbz/biblio/60/60rbz589-594.pdf
21. Ang, A., et al. (2012). Low genetic variability in the recovering urban banded leaf monkey population of Singapore. The Raffles Bulletin of Zoology, 60(2), 590. Retrieved from http://lkcnhm.nus.edu.sg/rbz/biblio/60/60rbz589-594.pdf
22. Ang, A. (2016). The plight of the Asian Colobines: Profiling Singapore’s banded leaf monkey and Vietnam’s Tonkin snub-nosed monkey. Asian Geographic, 1(116), 43.
23. Ang, A., et al. (2012). Low genetic variability in the recovering urban banded leaf monkey population of Singapore. The Raffles Bulletin of Zoology, 60(2), 590. Retrieved from http://lkcnhm.nus.edu.sg/rbz/biblio/60/60rbz589-594.pdf
24. Ang, A., et al. (2012). Low genetic variability in the recovering urban banded leaf monkey population of Singapore. The Raffles Bulletin of Zoology, 60(2), 592. Retrieved from http://lkcnhm.nus.edu.sg/rbz/biblio/60/60rbz589-594.pdf
25. Ang, A., et al. (2012). Low genetic variability in the recovering urban banded leaf monkey population of Singapore. The Raffles Bulletin of Zoology, 60(2), 590. Retrieved from http://lkcnhm.nus.edu.sg/rbz/biblio/60/60rbz589-594.pdf
26. Presbytis femoralis ssp. femoralis. (2008). The IUCN red list of threatened species. Retrieved from http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T39801A10267835.en
27. Baker, N., et al. (2008). Wild animals of Singapore: A photographic guide to mammals, reptiles, amphibians and freshwater fishes. Singapore: Draco Publishing and Distribution; Nature Society (Singapore), p. 135. (Call no.: RSING 591.95957 WIL)



The information in this article is valid as at 2016 and correct as far as we are able to ascertain from our sources. It is not intended to be an exhaustive or complete history of the subject. Please contact the Library for further reading materials on the topic.

 

Subject
Wildlife
Presbytis--Singapore
Nature>>Animals
Langurs--Singapore
Science and technology>>Zoology>>Endangered animals

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