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, where behavioural problems occur and require enrichment and expert care (Gray et al. 2015, Moore et al. 2015). 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 these releases make a positive contribution to conservation remains to be seen (Moore et al. 2015).

There are permanent education programmes across parts of the range of N. javanicus, including ‘Slow Loris Forest Protector’ book and teachers pack, Nature Clubs, village Pride Days, film nights, and reforestation projects, working with farmers to explain the benefits of the slow loris to prevent pests and also as a pollinator (Nekaris 2014). There are ongoing campaigns to combat the number of slow lorises, including N. javanicus, observed in illegal social networking videos (Nekaris et al. 2015).


Location Information

This species is known from Java, Indonesia, where it occurs in primary, secondary and disturbed lowland to highland rainforest, bamboo forest, mangrove forest and plantations from Banten, the westernmost province, to central Java (Thorn et al. 2009). Nycticebus javanicus been found in the following localities:  Ujung Kulon, Gunung Gede Pangrango, Meru Betiri, Gunung Tilu, Gunung Simpang, and Gunung Sawa (Thorn et al. 2009, Voskamp et al. 2013). They may also occur on Gunung Halimun (border of Banten and West Java provinces) and Gunung Masgit Kareumbi (west Java), the Dieng Highlands (Central Java) and Bromo Tengger Semeru National Park (East Java). It occurs in East Java in the Meru Betiri and Alas Purwo national parks (Lehtinen et al. 2013, Voskamp et al. 2013). It probably occurred throughout the island in the past.

Geographic Range



Population Information

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, Carita Nature Recreation Park, Gunung Gede Pangrango, Cibodas, Talaga Sumrut Game Reserve, Masigit Kareumbi, Slamet, Dieng) (Voskamp et al., 2013) indicating a decline of over 80% in the population over its range. 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; Voskamp et al., 2013). A specific survey in Gunung Gede Pangrango reported a density of 15.6 individuals/km², with a calculation that some 70 slow lorises occupy the study area (Nekaris et al., 2014). Based on the results of the survey, a very slow walking speed was deemed important in being able to detect slow lorises. More recently Nekaris and colleagues (unpublished) surveyed East Java, increasing the geographic range of N. javanicus, finding it at sites including Tumpang Pitu Forest, Meru Betiri National Park and Salakan Forest.

The population is inferred to have declined by over 80% over the last three generations (24 years) due to exploitation and declining availability of suitable habitat; less than 20% of suitable habitat suitable for Nycticebus javanicus remains. Severe population declines have been documented in forested habitats in Java (Wirdateti et al. 2004, 2011).


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, Nycticebus 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 kilometres of intensely modified and unsuitable habitat. The conversion of land to agricultural 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-leaping 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 Starr 2015). 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 (Musing et al. 2015). From there the species may appear on online videos which perpetuate the pet trade (Nekaris et al. 2013). 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 (Nekaris and Starr 2015). 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 et al. 2015).

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. coucangN. 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).


IUCN Red List Account Link

Please click here to see the species' IUCN Red List Account page.

Photo Credits

Andrew Walmsley (category and featured image)