Nycticebus javanicus, E. Geoffroy Saint-Hilaire, 1812

Russell A. Mittermeier, Anthony B. Rylands & Don E. Wilson, 2013, Lorisidae, Handbook of the Mammals of the World – Volume 3 Primates, Barcelona: Lynx Edicions, pp. 210-220 : 219

10.

Javan Slow Loris

Nycticebus javanicus

French: Loris de Java / German: Java-Plumplori / Spanish: Loris perezoso de Java

Taxonomy. Nycticebus javanicus E. Geoffroy Saint-Hilaire, 1812 ,

Java.

Considered monotypic here, despite some geographic variation, with evidence for two distinct forms.

Distribution. W & C Java, with an isolated locality in the E.

Descriptive notes. Head-body ¢.25 cm, tail vestigial; weight 750-1150 g. The Javan Slow Loris is a medium-sized, yellowish-gray form with little or no frosting.

The neck is creamy, and dorsalstripes and head forks are reddish to blackish, thin, and sharply marked. The pale color of the head, neck, and upper back of the Javan Slow Loris often cause confusion with the Bengal Slow Loris (N. bengalensis ), especially in museum collections, and indeed, these species are genetic sister taxa. The diamond pattern that forms between the eyes is a defining character of the Javan Slow Loris. Ears are small with tufts. The second incisor is always absent. Two forms occur throughout the year inJava—one with a short coat that is sometimes red, but often dark brown, and one with a very long coat that is always dark brown or very black. The latter was originally named N. ornatus. It remains to be seen if these are different taxa. Two of the same morph have not yet been seen at the same locality in the wild.

Habitat. Primary and secondary disturbed lowland to highland rainforest, bamboo forest, mangrove forest, and plantations, including chocolate plantations. The Javan Slow Loris can thrive in cultivated areas. It prefers interconnecting branches and vines up to 20 m off the ground. It goes to the ground, and crosses roads and tea plantations. It occurs from sea level to 1800 m.

Food and Feeding. Omnivorous. The Javan Slow Loris gouges gum from legumes such as Albizia (Fabaceae) and can create enormous holes while doing so. They can survive in farmbush where they also drink palm wine (alcoholic beverage made from the sap) and eat domestic crops. Reintroduced animals have spent 90% of the time licking up nectar, especially from Calliandra calothyrsus ( Fabaceae ) flowers. They feed predominantly in the terminal branches in a suspended position, where flowers are located visually. A combination of excessive flower visitation, non-destructive feeding, and pollen observed on their face suggest they act as pollinators. Wild Javan Slow Lorises rescued from the pet trade eat a variety of localfruits, but they consume birds, frogs, crickets, beetle larvae, rhinoceros beetles, land snails, eggs, cicadas, flying termites, and nearly any insect that lands in their cage with gusto.

Breeding. There is no specific information for this species other than they give birth to one infant at any time of the year.

Activity patterns. The Javan Slow Loris is nocturnal and arboreal. It moves rapidly on small branches despite being one of the larger lorises. It can move and forage on the ground, and it eats farm crops and gouges from gum sources close to the ground. It can climb on large trunks.

Movements, Home range and Social organization. Home ranges of radio-collared Javan Slow Lorises are 25-32 ha. They can move more than 600 m/hour and more than 5 km in a night linearly, not counting vertical distances. Javan Slow Lorises can occur in sleeping groups of up to seven animals (sex and age unknown) in bamboo. Wounds are very common in males and females, suggesting territorial fights. These wounds may be inflicted by the slow loris’s venom. Individuals are heavily hunted, and it is not known what disruption and impact hunting have on social organization, and thus on fighting. A whistle or irritated “chitter” is used during conflict. Other vocalizations include an affiliative “krik” call. Slow lorises also sometimes produce a low buzzing hiss or growl when mildly disturbed (e.g. when pushed out of a nest box). On making contact with other individuals, they emit a single high-pitched rising tone, and females use a high whistle when in estrus.

Status and Conservation. CITES Appendix I. Classified as Endangered on The IUCN Red Lust. Javan Slow Lorises are frequently captured as pets and for use in traditional Asian medicine. When keptalive, they have their teeth pulled to minimize biting people, which inevitably leads to their demise unless fed soft foods. The overall population of the Javan Slow Loris has declined by at least 50% over the past 24 years,in large part due to the pet trade. This decline and increasing and unsustainable hunting of the Javan Slow Loris led to it being placed on the list of the World’s 25 Most Endangered Primates in 2008. It occurs in three protected areas: Gunung Gede Pangrango and Ujung Kulon national parks and Mount Dieng Protected Forest in Indonesia. It may also occur in Meru Betiri National Park.

Bibliography. Groves (2001), Moore (2012), Munds et al. (2008), Nekaris & Bearder (2011), Nekaris & Munds (2010), Nekaris & Nijman (2007b), Nekaris, Blackham & Nijman (2008), Nekaris, Collins et al. (2010), Nekaris, Pimley & Ablard (2006, 2007), Nekaris, Sanchez et al. (2009), Nekaris, Shepherd et al. (2010), Nijman & van Balen (1998), Streicher et al. (2012), Winarti (2008).

Figures

1. Calabar Angwantibo (Arctocebus calabarensis), 2. Golden Angwantibo (Arclocebus aureus), 3. West African Potto (Perodicticus potto), 4. Milne-Edwards’s Potto (Perodicticus edwardsi), 5. East African Potto (Perodicticus ibeanus)

Distribution. W & C Java, with an isolated locality in the E.