Nycticebus javanicus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Primates Lorisidae

Scientific Name: Nycticebus javanicus É. Geoffroy, 1812
Common Name(s):
English Javan Slow Loris
Nycticebus coucang ssp. javanicus É. Geoffroy, 1812
Nycticebus ornatus Thomas, 1921
Taxonomic Notes: This taxon was considered a subspecies of Nycticebus coucang but elevated by Groves and Maryanto (2008). This is further supported by morphological studies by Nekaris and Jaffe (2007) and Nekaris and Munds (2010) and genetic studies by Roos (2003) and Wirdateti et al. (2006). Two distinct forms regularly occur in bird markets and further research is needed (Nekaris and Jaffe 2007). Care should be taken in taxonomic studies however due to translocation of individuals from markets into forests and gardens throughout the island (Schulze and Groves 2004). The distinct black and white long-haired appearance of subadults and juveniles also might be mistaken as separate species, for example, in museum specimens or from photos only (A. Nekaris et al. pers. comm. 2012).

Assessment Information [top]

Red List Category & Criteria: Critically Endangered A2cd+4cd ver 3.1
Year Published: 2013
Date Assessed: 2013-08-02
Assessor(s): Nekaris, K.A.I. , Shekelle, M, Wirdateti, Rode, E.J. & Nijman, V.
Reviewer(s): Schwitzer, C.
This species is listed as Critically Endangered based on a combination of historic forest loss and continued degradation meaning that less than 20% of habitat suitable for N. javanicus remains. Species distribution modelling and a gap analysis have also revealed that the remaining subpopulations of N. javanicus are highly fragmented, with only 17% of the potential distribution within the protected area network (Thorn et al. 2009). Adding to this, the species has experienced a suspected decline of at least 80% over the last 24 years (equals three generations; Nadler et al . 2007) due to severe and persistent and ongoing persecution for the pet trade (Nekaris et al. 2010).
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species is only known from the provinces of Banten, West Java, and at least as far east as the western part of East Java in Indonesia.
Countries occurrence:
Indonesia (Jawa)
Additional data:
Upper elevation limit (metres):1600
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:This species has been recorded at very low densities (0.02-0.20/km) (Nekaris et al. 2008). Several surveys in large forest blocks revealed few or no slow loris (Ujung Kulon, Halimun-Salak, Gede Pangrango, Masigit Kareumbi, Slamet, Dieng). Some small isolated populations persist in gardens and agricultural lands where they are at high risk from hunting and easily poached for the pet trade; severe population declines in these habitats have been documented (Wirdateti et al. 2004, 2011).
Current Population Trend:Decreasing
Additional data:
Population severely fragmented:Yes

Habitat and Ecology [top]

Habitat and Ecology:This species is nocturnal and arboreal, and is found in secondary disturbed forest, in plantations and to some extent in primary forests. It needs arboreal connectivity (vines and lianas) due to its unique locomotor adaptations, although it can cross short open spaces on the ground. It feeds on sap and floral florescence and gum but also on fruit and insects (Moore 2012; Wirdateti et al. 2004, 2011; A. Nekaris et al. unpublished data). The species sleeps alone, but more commonly in units of two or three individuals and in groups of up to six, in vegetation ranging from 2-30 m. It is often found in dense bamboo or branch tangles but not in tree holes (Wirdateti et al. 2004; A. Nekaris et al. unpublished data). Home ranges vary with habitat, ranging from 3-30 ha. Although often seen alone, social pairs and trios can occur, as can adult infant/juvenile pairs. Occurs from sea level to 1,600 m, although it is less common at higher elevations.
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):8

Use and Trade [top]

Use and Trade: This species is used for traditional medicines (Nekaris and Nijman 2007) and as a pet species.

Threats [top]

Major Threat(s):

Java is one of the world’s most densely populated areas and has a long history of deforestation. Extensive habitat loss and fragmentation threaten the Javan Slow Loris throughout its range. In comparison to other Indonesian slow lorises, N. javanicus is significantly more vulnerable to anthropogenic activity due to intensive land use by humans (Thorn et al. 2009). Lack of connectivity between protected areas also poses a threat to loris populations, with every forest area containing slow lorises being effectively isolated by several km of intensely modified and unsuitable habitat. The conversion of land to agriculural plantations is correlated with a sharp decline in slow loris population over the last 10 years (Wirdateti and Dahrudin 2011).

This species, like other slow lorises in Indonesia, is caught for use in the pet trade and to a lesser extent for traditional beliefs and folk medicines (Nekaris et al. 2010, Shepherd et al. 2004). Together with other loris species, N. javanicus is one of the most common protected primates found in animal markets in Java (Nekaris et al. 2008, Thorn et al. 2009). Due to their non-saltatory locomotion, their choice of sleeping sites in trees and bamboo that can be cut through and accessed, and nocturnal habits, the animals are easily caught by humans (Nekaris and Bearder 2011). The majority of the trade is to satisfy a large domestic demand, with a smaller proportion being smuggled abroad to destinations like the Middle East and Japan. The trade chain poses a perilous threat for many reasons. Conditions during transport (stuffed in boxes or sacks) and inappropriate husbandry techniques (poor diet and social housing, forced diurnal activity, excessive handling) afterwards result in large mortality rate. Slow lorises are the only venomous primates; to avoid their bites middle men or traders cut or remove teeth, a process that almost invariably leads to the animal’s death. If confiscated, reintroduction to the wild has proven difficult. Animals with no teeth are not viable candidates, and in a two-year study of 11 healthy radio-collared animals released, only two are known to have survived (Moore 2012).

Hybridization poses a real threat both on Java and elsewhere. Some taxa of slow loris are known to hybridize in zoos. Javan Slow Lorises have been observed on animal markets outside Java (e.g. Medan, Bandar Lampung on Sumatra) and other Indonesian slow loris species (N. coucang, N. menagensis) have been observed to Javan markets. Due to the morphological similarity of Nycticebus spp. misidentification is rife. Furthermore, there is a general feeling that ‘if it is a slow loris, release it.’ Not only does this pose welfare risks to the individual, but also translocated individuals may harbour infections and parasites, and could potentially hybridize (Nekaris et al. 2008, Schulze and Groves 2004).

Conservation Actions [top]

Conservation Actions:

This species is protected by Indonesian law (No. 5 of 1990) and is listed on CITES Appendix I. It is currently represented in three captive collections (Jakarta, Indonesia; Singapore; Saitama Children’s Zoo, Japan); it should be noted the specimen in Prague Zoo is in fact a N. coucang. There is no viable captive breeding programme, and reproduction in captivity is known to be difficult. Some ecological studies with conservation education components have been completed or are in progress. Training workshops have been conducted to provide law enforcement officers, CITES officials and zoo and rescue centre personnel with improved identification skills to identify Nycticebus spp. within the pet trade. Several rescue centres in the region maintain facilities for confiscated individuals. Numerous attempts have been made to release slow lorises, both monitored and unmonitored, but until more is known about the complexities of taxonomy and ecology of lorises within the region, whether or not these releases make a positive contribution to conservation remains to be seen.

Classifications [top]

1. Forest -> 1.6. Forest - Subtropical/Tropical Moist Lowland
suitability:Suitable season:resident major importance:Yes
1. Forest -> 1.9. Forest - Subtropical/Tropical Moist Montane
suitability:Suitable season:resident major importance:Yes
14. Artificial/Terrestrial -> 14.3. Artificial/Terrestrial - Plantations
suitability:Suitable season:resident major importance:Yes
14. Artificial/Terrestrial -> 14.4. Artificial/Terrestrial - Rural Gardens
suitability:Suitable season:resident major importance:Yes
1. Land/water protection -> 1.1. Site/area protection
1. Land/water protection -> 1.2. Resource & habitat protection
2. Land/water management -> 2.1. Site/area management
3. Species management -> 3.1. Species management -> 3.1.1. Harvest management
3. Species management -> 3.1. Species management -> 3.1.2. Trade management
4. Education & awareness -> 4.1. Formal education
4. Education & awareness -> 4.3. Awareness & communications
5. Law & policy -> 5.4. Compliance and enforcement -> 5.4.2. National level

In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
  Occur in at least one PA:Yes
In-Place Species Management
  Subject to ex-situ conservation:Yes
In-Place Education
  Subject to recent education and awareness programmes:Yes
  Included in international legislation:Yes
  Subject to any international management/trade controls:Yes
1. Residential & commercial development -> 1.1. Housing & urban areas
♦ timing:Ongoing ♦ scope:Whole (>90%) ♦ severity:Very Rapid Declines ⇒ Impact score:High Impact: 9 
→ Stresses
  • 1. Ecosystem stresses -> 1.1. Ecosystem conversion
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

2. Agriculture & aquaculture -> 2.1. Annual & perennial non-timber crops -> 2.1.2. Small-holder farming
♦ timing:Ongoing ♦ scope:Whole (>90%) ♦ severity:Very Rapid Declines ⇒ Impact score:High Impact: 9 
→ Stresses
  • 1. Ecosystem stresses -> 1.1. Ecosystem conversion
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

5. Biological resource use -> 5.1. Hunting & trapping terrestrial animals -> 5.1.1. Intentional use (species is the target)
♦ timing:Ongoing ♦ scope:Whole (>90%) ♦ severity:Rapid Declines ⇒ Impact score:High Impact: 8 
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

5. Biological resource use -> 5.3. Logging & wood harvesting -> 5.3.5. Motivation Unknown/Unrecorded
♦ timing:Ongoing ♦ scope:Whole (>90%) ♦ severity:Very Rapid Declines ⇒ Impact score:High Impact: 9 
→ Stresses
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

8. Invasive and other problematic species, genes & diseases -> 8.1. Invasive non-native/alien species/diseases -> 8.1.2. Named species [ Unspecified Nycticebus ]
♦ timing:Ongoing ♦ scope:Majority (50-90%) ♦ severity:Slow, Significant Declines ⇒ Impact score:Medium Impact: 6 
→ Stresses
  • 2. Species Stresses -> 2.3. Indirect species effects -> 2.3.1. Hybridisation

1. Research -> 1.1. Taxonomy
1. Research -> 1.2. Population size, distribution & trends
1. Research -> 1.5. Threats
1. Research -> 1.6. Actions
3. Monitoring -> 3.1. Population trends

♦  Medicine - human & veterinary
 Local : ✓ 

♦  Pets/display animals, horticulture
 Local : ✓   National : ✓ 

Bibliography [top]

Groves, C. and Maryanto, I. 2008. Craniometry of slow lorises (genus Nycticebus) of insular Southeast Asia. In: M. Shekelle, T. Maryano, C. Groves, H.; Schulze and H. Fitch-Snyder (eds), Primates of the Oriental Night, pp. 115-122. LIPI Press, West Java, Indonesia.

Groves C.P. 2001. Primate Taxonomy. Smithsonian Institution Press, Washington, DC, USA.

IUCN. 2013. IUCN Red List of Threatened Species (ver. 2013.2). Available at: (Accessed: 13 November 2013).

Moore, R.S. 2012. Ethics, ecology and evolution of Indonesian Slow Lorises (Nycticebus spp.) rescued from the pet trade. Oxford Brookes University .

Nadler, T. Thanh, V.N. and Streicher, U. 2007. Conservation status of Vietnamese primates. Vietnamese Journal of Primatology 1: 7-26.

Nekaris, K.A.I. and Bearder, S. 2011. The Lorisiform primates of Asia and Mainland Africa: diversity shrouded in darkness. In: C. Campbell, A. Fuentes, K. MacKinnon, S.K. Bearder and R.M. Stumpf (eds), Primates in Perspective, pp. 34-54. Oxford University Press, Oxford, UK.

Nekaris, K.A.I. and Jaffe, S. 2007. Unexpected diversity within the Javan slow loris trade: implications for slow loris taxonomy. Contributions to Zoology 76: 187-196.

Nekaris, K.A.I. and Munds, R. 2010. Chapter 22: Using facial markings to unmask diversity: the slow lorises (Primates: Lorisidae: Nycticebus spp.) of Indonesia. In: S. Gursky-Doyen and J. Supriatna (eds), Indonesian Primates, pp. 383-396. Springer, New York.

Nekaris, K.A.I. and Nijman, V. 2007. CITES proposal highlights rarity of asian nocturnal primates (Lorisidae: Nycticebus). Folia Primatologica 78: 211-214.

Nekaris, K.A.I., Blackham, G.V. and Nijman, V. 2008. Conservation implications of low encounter rates of five nocturnal primate species (Nycticebus spp.) in Asia. Biodversity and Conservation 17(4): 733-747.

Nekaris, K.A.I., Shepherd, C.R., Starr, C.R. and Nijman, V. 2010. Exploring cultural drivers for wildlife trade via an ethnoprimatological approach: a case study of slender and slow lorises (Loris and Nycticebus) in South and Southeast Asia. American Journal of Primatology 72(10): 877-886.

Roos, C. 2003. Molekulare Phylogenie der Halbaffen, Schlankaffen, und Gibbons. Technischen Universität.

Schulze, H. and Groves, C.P. 2004. Asian lorises: taxonomic problems caused by illegal trade. In: T. Nadler, U. Streicher U. and H. Thang Long (eds), Conservation of Primates in Vietnam, Frankfurt Zoological Society, Frankfurt.

Shepherd, C.R., Sukumaran, J. and Wich, S.A. 2004. Open season: an analysis of the pet trade in Medan, Sumatra, 1997-2001. TRAFFIC Southeast Asia, Selangor, Malaysia.

Thomas, O. 1921. Two new species of slow-loris. Annals and Magazine of Natural History 8: 627-628.

Thorn, J.S., Nijman, V., Smith, D. and Nekaris, K.A.I. 2009. Ecological niche modeling as a technique for assessing threats and setting conservation priorities for Asian Slow Loris (Primates: Nycticebus). Diversity and Distributions 15: 289–298.

Wirdateti and Dahrudin, H. 2011. Distribution and habitat Javan Loris (Nycticebus javanicus) in Halimun Park and garden area Garut District. Program Insentif dan Perekayasa LIPI-Ristek 2011.

Wirdateti, Dahrudin, H. and Sumadidjaya, A. 2011. Distribution and habitat of Javan Loris (Nycticebus javanicus) in plantations at Lebak District and Salak Mount (West Java). Journal Zoo Indonesia 20(1): 17-26.

Wirdateti, Okayama, T. and Kurniati, H. 2006. Genetic diversity of slow loris (Nycticebus coucang) based on mitochondrial DNA . Tropics 15(4): 377-381.

Wirdateti, Setyorini, L.E., Suparno and Handayani, T.H. 2004. Feeding and habitat of Slow Loris (Nycticebus coucang javanicus) in Badui Tribe conservation forest, Rangkasbitung-south Banten . Biodiversitas 6(1): 45-49.

Citation: Nekaris, K.A.I. , Shekelle, M, Wirdateti, Rode, E.J. & Nijman, V. 2013. Nycticebus javanicus. The IUCN Red List of Threatened Species 2013: e.T39761A17971158. . Downloaded on 18 July 2018.
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