Northern white-cheeked gibbon
Northern white-cheeked gibbon | |
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Adult male | |
Adult female | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Primates |
Suborder: | Haplorhini |
Infraorder: | Simiiformes |
Family: | Hylobatidae |
Genus: | Nomascus |
Species: | N. leucogenys
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Binomial name | |
Nomascus leucogenys (Ogilby, 1840)
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Northern white-cheeked gibbon range (brown — extant, orange — probably extinct) | |
Synonyms | |
Hylobates leucogenys (Ogilby, 1840) |
The northern white-cheeked gibbon (Nomascus leucogenys) is a Critically Endangered species of gibbon native to South East Asia.
It is closely related to the
The genome of N. leucogenys was sequenced and published in 2011.[5]
Description
Northern white-cheeked gibbons are
Like other members of their genus, both males and females have unusually long arms, even for gibbons, with the arms being 1.2 to 1.4 times as long as the legs. They are also more muscular, with heavier thighs and shoulders that suggest a greater bodily strength.[7] Adults have been shown to demonstrate a hand preference while swinging through the trees, with individuals being equally likely to be right or left handed.[8]
The species closely resembles the southern white-cheeked gibbon, but has slightly longer body hair and subtly different vocalisations. The males can also be distinguished by the shape of the white patches on their cheeks; in the northern species, these reach the upper borders of the ears, and do not touch the corners of the mouth, whereas in the southern species, they reach only half way to the ears and entirely surround the lips.[6]
Both males and females have been reported to produce reddish-brown secretions from glands around their upper chest, hips, and ankles. However, samples of sweat taken from the axillae and chest possess lower levels of steroids in white-cheeked gibbons than in many other species of ape, suggesting that olfactory signals may be less important in these animals than in their relatives.[6]
Distribution and habitat
Today, the northern white-cheeked gibbon is found only in northern Vietnam and northern Laos.[1] They were formerly also known from southern China, in Yunnan province, where they were reported to be on the edge of extirpation in 2008.[9] They were confirmed to be extinct in China in 2013.[10]
In Laos, a population of 57 gibbon groups was estimated at the
In Vietnam, at least 22 groups of N. leucogenys were confirmed in
No subspecies are currently recognised, although the southern white-cheeked gibbon was formerly considered to be a subspecies of N. leucogenys. The gibbon inhabits primary evergreen
Behaviour and diet
The northern white-cheeked gibbon is arboreal in habits, and primarily herbivorous, feeding mainly on fruits, with some leaves, buds, and flowers. However, up to 10% of their diet may be composed of insects and other small animals. They are generally sociable, living in groups of up to six individuals. Individual groups do not travel far, and are believed to be territorial. They are diurnal, and spend the night sleeping in high branches, often embracing one another tightly.[6] Behavioural studies have demonstrated that they are capable of self-recognition in mirrors.[15]
The calls of northern white-cheeked gibbons are among the most complex of those produced by gibbons, and are significantly different between males and females. The most distinctive calls are those made as part of male-female duets. These begin with the female making a series of 15 to 30 notes with an increasing pitch, followed by the male complex call with rapid changes of frequency modulation. The cycle, which lasts less than 20 seconds, then repeats with increasing intensity for five to 17 minutes.[6] In the closely related southern species, such duets are most common at dawn, and are apparently only made on sunny days.[16] In captive studies, males and females that sing duets together the most frequently are the most likely to mate, indicating this may play a key role in pair-bonding.[17]
Similar calls are sometimes made solo by both sexes, and juveniles sometimes join in, to create a full 'chorus'. In addition to the duet and solo great calls, males can also make booming sounds with their gular sacs, and short single notes.[6]
Reproduction
Northern white-cheeked gibbons are
At birth, both sexes are covered in yellow-buff fur, and weigh an average of 480 g (17 oz).[19] Around one year of age, the fur in both sexes changes to a black colour, with pale cheek patches, with the sexually dimorphic adult coats only growing when they reach four or five years. During this period, the juveniles sing the female form of call, and regularly engage in play behaviour.[20]
Northern white-cheeked gibbons reach sexual maturity at seven or eight years, and have lived for at least 28 years in the wild.[6]
References
- ^ . Retrieved 19 November 2021.
- ^ "Appendices | CITES". cites.org. Retrieved 2022-01-14.
- OCLC 62265494.
- ^ Geissmann, Thomas (December 1995). "Gibbon systematics and species identification" (PDF). International Zoo News. 42: 472. Retrieved 15 August 2008.
- ^ Ensembl entry
- ^ doi:10.1644/890.1.
- PMID 21892236.
- ^ Barker, M.K. (2008). "Gibbon hand preference studies at the Endangered Primate Rescue Center, Vietnam" (PDF). Vietnamese Journal of Primatology. 1 (2): 41–45. Archived from the original (PDF) on 30 December 2008.
- ^ Fan, P.F. & Huo, S. (2009). "The northern white-cheeked gibbon (Nomascus leucogenys) is on the edge of extinction in China" (PDF). Gibbon Journal. 5: 44–52. Archived from the original (PDF) on 14 September 2012.
- S2CID 86688210.
- S2CID 202854148.
- ^ Luu Tuong Bach & Rawson, B. M. (2011). Population assessment of the northern white-cheeked crested gibbon (Nomascus leucogenys) in Pu Mat National Park, Nghe An province. Conservation International / Fauna & Flora International, Hanoi, Vietnam
- ^ La, Q. T., Bui, T. T., Lo, V. O., Le, T. A., & Nguyen, M. H. (2020). Report on monitoring of the northern white-cheeked gibbon (Nomascus leucogenys) in Xuan Lien nature reserve, Thanh Hoa province, Vietnam. Center for Nature Conservation and Development, Ha Noi, Vietnam
- ^ Nguyen, M. H., Do, T., Le, V. D., Pham, A. T., Do, T. H., & Tran, D. H. (2012). The gibbon in Xuan Lien and Pu Hoat: An urgent call for conservation attention. Unpublished report.
- PMID 10994841.
- ^ Ha, N.M. (2007). "Survey for southern white-cheeked gibbons (Nomascus leucogenys siki) in Dak Rong Nature Reserve, Quang Tri Province, Vietnam" (PDF). Vietnamese Journal of Primatology. 1 (1): 61–66. Archived from the original (PDF) on 30 December 2008.
- S2CID 20771724.
- .
- S2CID 43659374.
- S2CID 35762611.
External links
- Northern White-cheeked Gibbon at Animal Diversity Web
- View the Nomascus leucogenys genome on Ensembl
- Genome of Nomascus leucogenys (version GGSC Nleu3.0/nomLeu3), via UCSC Genome Browser
- Data of the genome of Nomascus leucogenys, via NCBI
- Data of the genome assembly of Nomascus leucogenys GGSC Nleu3.0/nomLeu3, via NCBI