Nycticebus coucang (Boddaert, 1785)
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publication ID |
https://doi.org/ 10.5281/zenodo.6632647 |
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DOI |
https://doi.org/10.5281/zenodo.6632628 |
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persistent identifier |
https://treatment.plazi.org/id/039C9423-FFF0-087F-3468-D0E3523AF86B |
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Carolina |
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scientific name |
Nycticebus coucang |
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Sunda Slow Loris
Nycticebus coucang View in CoL
French: Loris lent / German: Sunda-Plumplori / Spanish: Loris perezoso de Sonda
Other common names: Greater Slow Loris, Sumatran Slow Loris
Taxonomy. Tardigradus coucang Boddaert, 1785 View in CoL
Malaysia, Malacca .
Initial research seems to indicate that there may be two distinct forms on Sumatra and that populations in Singapore, Malaysia, peninsular Thailand, and Bangka are also very distinct. There is a small hybrid zone of this species and N. bengalensis in the south of peninsular Thailand. Monotypic.
Distribution. S Thailand, Peninsular Malaysia (including Pinang, Langkawi & Tioman Is), Singapore, and Sumatra, also Malacca Straits Is and Riau Archipelago (Batam, Galang, Tebingtinggi), and Bunguran in the North Natuna Is. View Figure
Descriptive notes. Head-body 30-34 cm, tail vestigial; weight 635-850 g. The Sunda Slow Loris is small to medium-sized and the most richly colored of the lorises, with pelage light brown to crimson red and slight frosting on the flanks, and not paler on the neck. The chestis a little grayer than the belly. There is a variable broad, dark dorsal stripe that divides on the head into two distinct branches and encircles the eyes—the pattern of this stripe and the circumocular fork shapes may prove to be useful in identifying the Sunda Slow Loris. Color of the circumocular patch varies depending on the region from where an individual comes, and it may be region-specific. Ears are short.
Habitat. Primary and secondary lowland rainforest, lower freshwater swamp forest, secondary Padang savanna and resin plantations. The Sunda Slow Loris can be found in forest edge among interconnecting branches and vines, up to 20 m above the ground. It also occurs in relatively urban areas, feeding near street lamps.
Food and Feeding. Diet of the Sunda Slow Loris includes mainly fruits, supplemented with leaves, shoots, saps, gums, flowers, seeds, bird eggs, and animal prey (including insects and the occasional bird). Its diet in Malaysia comprised five food types: floral nectar and nectar-producing parts mainly from flowers of the bertram palm (Eugeissona tristis, Arecaceae), phloem sap,fruits, gum, and arthropods. The largest proportion of feeding time was spent on phloem sap (34:9%), floral nectar and nectar-producing parts (31:7%), and fruits (22:5%). Sunda Slow Lorises gouge with their toothcomb to extract gum, excavating large holes in the wood of trees, and use their long tongues to lap it up. Their slow metabolic rate is linked to detoxifying toxic compounds in this plantrich diet.
Breeding. Breeding may occur at any time of the year. Female Sunda Slow Lorises are at peak sexual receptivity every 42 days, and their mating call tends to increase in frequency at this time. Normally, a single young is born (occasionally twins) after a 185— 197day gestation. It is difficult to know how accurate this gestation length is because most slow lorises in captivity seem to be Bengal Slow Lorises or hybrids. Newborns are gray with silvery-white limbs and hands, with long glistening hairs that disappear after about eleven weeks. Young cling to their mother until they are four to six weeks old. She then parks them. Rather than learning how to choose food sources by scrounging from the mother, infant Sunda Slow Loris seem to use other mechanisms, one of which may be scent because this species vigorously scent-marks both floral nectaries and gum sites. Captive individuals live for 20 years or more.
Activity patterns. The Sunda Slow Loris is nocturnal and arboreal. It is a slow climber but capable of rapid and steady movement through a continuous canopy. It prefers the small-branch niche but can move on trunks and on the ground to cross roads and fields.
Movements, Home range and Social organization. One to three Sunda Slow Lorises interact in overlapping home ranges of 10-25 ha. Adult males and adult females are highly territorial and defend their territories aggressively. Many individuals have numerous healed scars and wounds. The Sunda Slow Loris often occurs at very low densities (e.g. 0-01-0-02 ind/km?® in Pasoh Forest Reserve or 0-4 ind/km* in Petaling Jaya, both in Malaysia), but in some areas with better habitat, such as unlogged primary forest, densities are higher (e.g. 0-5—1-2 ind/km?® in the Sungai Tekam Forest, Malaysia or 1-6-4 ind/km?® in the Manjung District, Malaysia). Their social organization is unimale— unifemale, but mating is promiscuous, with multiple males pursuing a single estrous female. Social behaviors include allogrooming, foraging together and contact during the night, adult/infant play, and interactive vocalizations. Sunda Slow Lorises spend 3-10% oftheir time in social proximity during the night. Depending on the site, two to three individuals regularly sleep in contact. They use sleeping sites repeatedly but swap them regularly. They do not sleep in nests, and sleeping sites always comprise branch tangles, bamboo thickets, or dense lianas. Scent marking with urine is the dominant form of communication. Nevertheless, it is becoming clear that various calls are used by Sunda Slow Lorises, but it is difficult for humans to hear some of them. A whistle or irritated “chitter” may be used during conflict. Other vocalizations include an affiliative “krik” call, and a louder call resembling a crow’s caw specific to the Sunda Slow Loris. When mildly disturbed (e.g. when pushed out of a nest box in captivity), they may also produce a low buzzing hiss or growl. To make 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 Vulnerable on The IUCN Red List. Despite legal protection in Malaysia, Thailand, and Indonesia, Sunda Slow Lorises are frequently taken for use in the pet and medicinal trade, and they are occasionally shot as a crop pest. For the pet trade, incisors are often removed before sale, frequently causing infection and death; if an individual survives and is confiscated, it cannot be rehabilitated for release into the wild. They are frequently killed when crossing powerlines and roads. Although the Sunda Slow Loris is adaptable to various human-induced habitat changes, severe loss of forest cover is a serious threat. They are known to occur in Berbak, Gunung Leuser, and Kerinci-Seblat national parks in Indonesia and Klong Yan Wildife Sanctuary in Thailand. It may occur in the Central Catchment Nature Reserve in Singapore and in the Tarutao and Taman Negara national parks in Malaysia.
Bibliography. Acharjyo & Misra (1973), Alterman (1990), Alterman & Hale (1991), Barrett (1981), Chasen (1940), Dykyj (1980), Egozcue & Egozcue (1966), Ehrlich & Macbride (1989), Ehrlich & Musicant (1977), Elliot & Elliot (1967), Fooden (1991a), Garcia et al. (1978), Glassman & Wells (1984), Groves (2001), Heffner & Masterton (1970), lzard et al. (1988), Johns (1986a, 1986b), Montagna et al. (1961), Muller (1979), Munds et al. (2008), Napier & Napier (1967), Nekaris & Bearder (2007), Nekaris & Munds (2010), Nekaris & Nijman (2007a, 2007b), Nekaris, Collins et al. (2010), Nekaris, Shepherd et al. (2010), Rumpler et al. (1987), Seitz (1969), Stanyon et al. (2006), Su et al. (1998), Tenaza et al. (1969), Trent et al. (1977), Weisenseel et al. (1998), Wiens (1995, 2002), Wiens & Zitzmann (1999, 2003a, 2003b), Wilde (1972), Zimmermann (1985a, 1989b).
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