Greater slow loris  (Nycticebus coucang)

The greater slow loris is classified as Vulnerable (VU) on the IUCN Red List (1) and listed on Appendix I of CITES (2).

The greater slow loris (Nycticebus coucang) is a nocturnal and strictly arboreal primate. This species has a rounded head with a short snout and a stocky body. Colouration varies throughout the greater slow loris’ range, but the thick and woolly coat tends to be a light brown colour with a broad, dark brown stripe running along the midline of the back (3) (5) (6). The greater slow loris has dark brown patches around its large, circular eyes, which are separated by a white streak of fur ending at the nose (6).

Unlike many other primates, all species of loris only have a vestigial tail and instead use incredibly mobile wrist and ankle joints to manoeuvre along branches (3) (6). Opposable thumbs and an extensive network of narrow blood vessels in its limbs enable an effortless and powerful grasp, allowing the greater slow loris to tightly grip branches for hours at a time (3) (4).

The greater slow loris is found in Southeast Asia (3). Its range extends from the northern tip of Thailand, throughout the Malaysian peninsular to Indonesia and Singapore and some of the neighbouring islands (1).

This arboreal primate occurs mainly in primary and secondary tropical lowland forests, up to elevations of 1,300 metres (1) (3). The greater slow loris prefers forest edges, as insect prey and support branches are more abundant (3).

A nocturnal species, the greater slow loris hides high up in trees to sleep during the day, often on branches or palm fronds (5). It sleeps tightly curled in a ball while gripping nearby foliage for support (6).

The greater slow loris is a slow-moving species, and has a low metabolic rate compared to other mammals of its size (5).  It is unable to leap, and instead walks very slowly on all fours, keeping three feet in contact with the branches at all time (3) (5). While hunting, the greater slow loris may hang upside down from branches, leaving both hands free to catch flying insects, preferring insects with a pungent taste and smell (4) (6). This species also feeds on fruit, small animals, birds eggs, and gum from trees (4).  

Gestation in the greater slow loris lasts for 191 days, after which a single young is born (3) (4). Birth takes place at night, and the newborn immediately climbs up to the deep, concealing fur of the female’s belly, and clings on with its hands and feet (6). The infant is only removed from this protected position while the female forages (3) (4).

The greater slow loris is threatened by the unsustainable and poorly regulated pet and traditional medicine trades (7). Local people, especially in Cambodia, believe the slow loris to cure a number of diseases, and in Indonesia, this species is more commonly traded as a live pet (7). Its toxic bite means that teeth are usually removed, often leading to infection, dental abscesses and death as it is unable to eat its preferred diet (8). It is easily targeted by poachers, as this species clings tightly to the branches rather than escaping, is stunned by bright daylight, and is very slow moving  (7) (8).

Like all Asian species of loris, habitat loss due to deforestation has also contributed to a large reduction in numbers of the greater slow loris (7).

The greater slow loris is found in several protected areas within its range and is on the Cambodian and Indonesian protected species lists. It is also protected by law in Malaysia and Thailand, although protection is rarely enforced and the penalties to deter hunters and traders are too low to be effective (1) (7).

All species of slow loris are listed on Appendix I of the Convention of International Trade of Endangered Species (CITES), which protects the greater slow loris from international commercial trade (2).

View information on this species at the UNEP World Conservation Monitoring Centre.

For further information on primate conservation see:

• IUCN/SSC Primate Specialist Group:
  http://www.primate-sg.org/

To learn more about loris protection and conservation see:

• Loris Conservation:
  http://www.loris-conservation.org/