PIN still needs volunteers, including students of primatology, who are working directly with species and also peer reviewers to help us update our fact sheets. In the meantime, we welcome readers to send updates for consideration. We will evaluate suggestions with experts, then consider adding these updates in context and in parentheses, along with “This content is provided as a courtesy to PIN readers and is not part of the original peer-reviewed fact sheet. Current date/year.” We advise our readers to use our fact sheets as just one source of information and to always research additional sources.
Species: N. bengalensis, N. coucang, N. javanicus, N. pygmaeus
Subspecies: N. c. coucang, N. c. menagensis
Other names: N. bengalensis: N. cinereus, N. incanus, N. tenasserimensis, Bengal slow loris, Bengal loris, northern slow loris; N. coucang: N. brachycephalus, N. buku, N. hilleri, N. insularis, N. malaiana, N. natunae, N. sumatrensis, N. tardigradus, greater slow loris, slow loris, Sunda slow loris; loris lent (French); loris lento (Spanish); tröglori (Swedish); N. c. menagensis: N. menagensis, N. bancanus, N. borneanus, N. philippinus, Bornean slow loris; N. javanicus: N. ornatus, Javan slow loris; N. pygmaeus: N. intermedius, pygmy slow loris, lesser slow loris, pygmy loris; dvärgtröglori, mindre tröglori (Swedish).
Total population: Unknown
Regions: Southeast Asia
Gestation: approx. 6 months
Height: N. coucang 27 to 38 cm, N. pygmaeus 19 to 22 cm
Weight: 265 to 1605 g
There is significant size variation across the genus Nycticebus, with some types (N. bengalensis) over two times the weight of other types (N. c. menagensis) (Ravosa 1998). Some of the size variation is clinal over the distribution of the genus, however N. bengalensis and N. pygmaeus are sympatric and N. pygmaeus is quite smaller than N. bengalensis (Ravosa 1998). Head and body length of N. coucang is 27-38 cm (10.6-15.0in) and N. pygmaeus is around 19-22 cm (7.5-8.7) (Rigel 2004; Ankel-Simons 2007; Streicher 2007). Recorded slow loris body masses are N. bengalensis (1134-1605g (40.0-56.6oz), N. c. coucang (599-685g (21.1-24.2oz)), N. c. menagensis (265-300g (9.3-10.6oz)), N. javanicus (565-687g (19.9-24.2oz)), and N. pygmaeus (418-422g (14.7-14.9oz)) (Nekaris et al. 2008). Male and female N. pygmaeus do not differ significantly in head and body length, while they do in body weight, with males weighing somewhat more than females (Kappeler 1991; Streicher 2007). However, N. coucang do not show sexual dimorphism by weight (Kappeler 1991).
In general, there is a whitish strip between the eyes, starting on the forehead and continuing until the end of the nose. The head is round and the ears are hidden in thick fur which characterizes slow lorises as a whole. The tail is reduced to a stump and is also hidden in the fur (Ankel-Simons 2007). The eyes are large (Choudhhury 1992). The second digit is short, and the hand performs as a powerful clamp for grasping (Ankel-Simons 2007). N. coucang has light brown pelage, with a dark stripe down its back (Groves 2001). N. javanicus is yellow-gray with a dark to black stripe down its back. N. bengalensis is orange-buff or warm orange, with a grey neck and a thin brown stripe down its back (Duckworth 1994; Groves 2001). Overall, N. pygmaeus is dull reddish, medium to dark brown and gray-brown with very thick fur, and is darker dorsally than ventrally (Duckworth 1994; Groves 2001; Streicher 2004b; Ankel-Simons 2007). It is also important to remember however, that there are seasonal changes in pelage coloration in N. pygmaeus (Streicher 2004b). Slow lorises have glands on their elbows that secrete a strong-smelling liquid used in communication (Hagey et al. 2007).
Movement is typically slow, with three limbs almost always in contact with whatever the loris is moving on (Wiens 2002; Rigel 2004). Slow lorises are capable of quadrupedal movement, both above, and while suspended from, a support in their environment (Ishida et al. 1986). In captivity, movement (N. coucang) is quadrupedal (24%), climbing (21%), suspension (including cantilevering) (29%), bridging (23%), and in other forms of locomotion (3%) (Gebo 1987). Slow loris movement is a unique type of quadrupedalism, which is very deliberate (almost reminiscent of crawling or as if the animal was climbing in any direction it is moving), changing direction or moving between supports without much noise or change in speed (review in Jouffroy 1989). Lorisids, including Nycticebus do not leap between supports and are almost fully arboreal, rarely coming to the ground (Curtis 1995; Huynh 1998).
In captivity, members of the genus Nycticebus have lived up to a little over 25 years (Weigl 2005).
CURRENT RANGE MAPS (IUCN REDLIST):
Nycticebus bengalensis | Nycticebus coucang coucang | Nycticebus coucang menagensis | Nycticebus javanicus | Nycticebus pygmaeus
In general, slow lorises are found in southeast Asia, ranging from eastern India (east of the Brahmaputra River) to Indochina and southern China south to the Malay peninsula and Java, Borneo and the far western Philippine islands (Simunul, Bongao, Sanga Sanga, and Tawitawi) near Borneo (Groves 1971; Zhang et al. 1981; Fooden 1991). N. bengalensis has the largest range of the genus, and is found in Myanmar, Cambodia, southern China, northeast India, Laos, Thailand, Vietnam, and Bangladesh (Khan & Ahsan 1986; Haque & Siddiqi 1988; Brandon-Jones et al. 2004; Nekaris & Bearder 2007; Nekaris et al. 2008). N. c. coucang is found in Indonesia, the Malay peninsula (Malaysia) and Thailand. N. c. menagensis is found in Brunei, Indonesia, Malaysia, and the far southwestern Philippines (Fooden 1991; Brandon-Jones et al. 2004; Nekaris et al. 2008). N. coucang is also found in Singapore (Nekaris et al. 2008). N. javanicus is only found on Java, Indonesia. Finally, N. pygmaeus is found in eastern Cambodia, south China, Laos, and Vietnam (Brandon-Jones et al. 2004; Nekaris et al. 2008). N. pygmaeus and N. bengalensis are sympatric, and have distributions that overlap in Laos, Vietnam, and southern China (Duckworth 1994; Wiens 2002). In general, it appears that slow lorises are rare in many areas of their distribution and are not always easily found even within their known range (Nekaris & Nijman 2007).
Reflecting their large distribution overall, slow lorises are found in a range of habitats including tropical rainforests to seasonal forests including tropical evergreen and semi-evergreen forests, seasonal wet evergreen, dry evergreen forest, mixed deciduous tropical forest, sub-tropical broadleaf hill forests, swamp forests, savannah, montane and submontane forests, shrub forests, peat swamp, primary forests and hardwood forests, as well as degraded habitats such as highly disturbed forests, secondary forests, disturbed primary forests and logged forests (Barrett 1981; Choudhury 1992; Duckworth 1994; Huynh 1998; Wiens et al. 2006; review in Nekaris et al. 2008). N. bengalensis prefers bamboo forest mixed with hardwood trees, farmbush and mangrove swamps, as well as peat swamp forest and low and tall interior forests while N. coucang is found in continuous canopy tropical rainforest (Nekaris & Bearder 2007; Nekaris et al. 2008). N. pygmaeus is found in bamboo forest mixed with hardwood trees, forest edge habitats, and dense scrub (Nekaris & Bearder 2007). The exact habitats of N. javanicus and N. c. menagensis are unknown (Nekaris & Bearder 2007).
At one long-term study site on the western coast of the Malay Peninsula, Malaysia, yearly rainfall averages 178.5 cm (70.3in), usually with a rainy season (Oct-Dec) and a dry season (Jun-Jul) (Wiens 2002; Wiens et al. 2006). At this site, the average annual temperature is 26.7°C (80.1°F), with little variation over the course of the year (Wiens et al. 2006).
At one study site in western Malaysia, slow lorises (N. coucang) spent their feeding time eating sap (34.9%), floral nectar and plant parts that produce nectar (31.7%), fruit (22.5%), and the rest gums and arthropods (including insects and spiders) with little seasonal change in proportions (Wiens et al. 2006). In a different short term study of reintroduced individuals, the pygmy loris (N. pygmaeus) ate 40% insects, 30% gum, and 30% other exudates (Streicher 2004a). Insects are caught in one or two hands, sometimes with the animal gripping its support bipedally. Exudates are ingested by licking trees, especially around wounds oozing gum (Streicher 2004a). There is some evidence to suggest that N. pygmaeus may purposefully gouge trees to induce the flow of exudates for consumption (Tan & Drake 2001).
Slow lorises are a nocturnal species, starting their nightly activity around sunset (Wiens 2002; Choudnury 1992). They have an extremely low metabolic rate relative to other mammals of their size and live a slow lifestyle (Wiens et al. 2006). Over the course of the night, most (93.3%) of their time is spent solitary. Feeding averages around 20.5% of the daily nightly activities with resting comprising only around 5.4 % (Wiens 2002).
Slow lorises (N. coucang) sleep during the day, rolled up in a ball in hidden parts of trees above the ground, often on branches, twigs, palm fronds, or lianas (Choudhury 1992; Wiens 2002). N. bengalensis sleeps often in tree holes or in dense brush, while N. coucang do not (Choudhury 1992; Wiens 2002). Individuals usually sleep alone but also occasionally sleep with other slow lorises, including other adults (Wiens 2002). Estimates indicate that an individual slow loris may use around sixty individual sleeping sites (Wiens & Zitzmann 2003b).
Recorded home ranges are highly variable, even within a single species (N. coucang). Recorded home ranges of this species range from 0.004 km² to 0.25 km² (0.0015 to 0.1 mi²), with significant overlap among adults (Wiens 2002; Wiens & Zitzmann 2003b). In one study, the average home range in forests was 0.034 km² (0.01 mi²), while in savanna the value was 0.148 km² (0.06 mi²) (Wiens & Zitzmann 2003b). The average home range of N. pygmaeus is 0.03 km² (0.01 mi²) (Nekaris & Bearder 2007).
Pythons (Python reticulatus) are a confirmed predator, as are hawk-eagles (Spizaetus cirrhatus) and orangutans (Pongo pygmaeus) (Utami & van Hooff 1997; Wiens & Zitzmann 1999; Hagey et al. 2007). Civets and owls do not elicit a response from slow lorises nor do the predators react to their presence (Wiens & Zitzmann 1999). Predatory attacks on slow lorises are avoided primarily through crypsis (Wiens & Zitzmann 1999; 2003b). Other methods of escape include merely falling away from the threat by releasing its support, biting (which can be painful) or rolling up in a defensive posture with the arms over the head and with elbow gland oils spread on its back (Tenaza & Fitch 1984).
Sympatric N. bengalensis and N. pygmaeus have been seen to forage simultaneously in the same tree, within several meters of one-another (Duckworth 1994).
Content last modified: March 18, 2009
Written by Kurt Gron. Reviewed by Helena Fitch-Snyder.
Cite this page as:
Gron KJ. 2009 March 18. Primate Factsheets: Slow loris (Nycticebus) Taxonomy, Morphology, & Ecology . . Accessed 2020 July 9.
For individual primate species conservation status, please search the IUCN Red List.
Also search the current scientific literature for primate conservation status (overall as well as for individual species), and visit CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora).
Conservation information last updated in 2009 follows, for comparison:
Threat: Human-Induced Habitat Loss and Degradation
Slow lorises are also particularly susceptible to habitat fragmentation and the felling of feed and sleeping trees causes habitat degradation and increased contact with people (Choudhury 2001; Medhi et al. 2004). In India, for example, habitat destruction is the worst threat to slow lorises (Choudhury 1992). Jhum cultivation (slash-and-burn cultivation) is also a significant habitat threat in India, as is tea cultivation and other agricultural land use (Choudhury 1992; Medhi et al. 2004). Often human settlements follow these types of land use, inhibiting secondary growth (Medhi et al. 2004). Other reasons for habitat descrution include monoculture, logging, fuel-wood extraction, land use for paper production, and the construction of infrastructure (Choudhury 1992). In China, habitat destruction is also the biggest threat to resident slow lorises and suitable areas are often destroyed for cash crops such as rubber, sugarcane, and coffee growing (Lan 1999).
Threat: Invasive Alien Species
Due to importation of slow lorises from some areas of their range to others, sometimes non-local species of slow loris (that are not properly identified) are introduced or released if confiscated into habitats in which they are not native, potentially altering the ecology of native species of slow loris (Schulze & Groves 2004).
Threat: Harvesting (hunting/gathering)
Over large areas of their range, slow lorises are collected as pets and for illegal folk medicine. They are one of the most commonly traded protected primates in southeast Asia (Schulze & Groves 2004; Nekaris & Jaffe 2007). In some areas, they are also hunted for meat (Radhakrishna et al. 2006). However, due to their diminutive size, N. pygmaeus are not hunted intensely, but they are probably still sold in markets in Vietnam and even exported (Duckworth 1994; Fitch-Snyder & Thanh 2002). Animals are often exported from their countries of origin for medicinal uses and very often end up in China, but illegal export to Taiwan has also been recorded (Phipps 1992; Fitch-Snyder & Thanh 2002). Even if the lorises are not desired locally, they are often collected in neighboring areas and imported (Schulze & Groves 2004). In China, slow lorises are eaten, the bones are used for medicinal uses, and the fur for local hunting bags (Lan 1999). The illegal trade in the species is further evidenced by slow lorises being found for sale in Indonesian and Cambodian markets. In some areas, the trade is so intense that devoted animal rescue centers are overwhelmed (Malone et al. 2002; Streicher et al. 2002; Nekaris & Jaffe 2007). In Vietnam, collection for medicinal purposes results in captured animals being dried or placed in rice wine (Streicher et al. 2002). Some groups across the broad slow loris range believe that the collection of a loris eyeball may help the person’s eyesight (Medhi et al. 2004). Adding to the threat of their removal from their habitats, slow lorises very often die from the stress of being held captive (Streicher 2004).
Threat: Accidental Mortality
While trying to cross roads, slow lorises are sometimes hit and killed by automobile traffic (Radhakrishna et al. 2006).
Threat: Human Disturbance
In some protected areas of India, armed insurgent groups are present. Such groups may hunt slow lorises, but also discourage the patrols of forest guards, and thus reduce protection afforded to slow lorises (Radhakrishna et al. 2006). Further, recent wars in Indochina have significantly altered or destroyed slow loris habitats (Lan 1999).
LINKS TO MORE ABOUT CONSERVATION
- Conservation Database for Lorises and Pottos
- Dr Anna Nekaris’ little fire face project (Saving the slow loris via ecology, education & empowerment)
- Husbandry Manual for Asian Lorisines (Nycticebus & Loris ssp.) (loris-conservation.org)
- Links for all species
- Strange endangered primates you may have never heard of (BBC; January 25, 2012)
- Animal picture of the day: radio collaring a slow loris (Mongabay; July 17, 2011)
- 70 percent of Indonesia’s primates in danger of extinction (BNO News; June 7, 2011)
- Slow loris YouTube videos fuel endangered species trade (The Telegraph; March 22, 2011)
- The loris: Another primate at risk from traditional Asian medicine (Scientific American; May 27, 2010)
- YouTube videos may be imperiling cuddly primate (Mongabay; February 24, 2009)
- Cuddly primate trade banned (Mongabay; June 11, 2007)
- Too cute for comfort (BBC News; June 7, 2007)
- Slow Lorises Smuggler Eludes Arrest In Thailand (Playfuls.com; March 1, 2007)
- Links for all species
ORGANIZATIONS INVOLVED IN Nycticebus CONSERVATION
- LVDI International
- Orangutan Tropical Peatland Project
- Community Conservation
- Israeli Primate Sanctuary
- Monkeyland Primate Sanctuary
- Rimrock Ranch Wildlife Conservancy, Ltd.
- Wildlife Friends Foundation Thailand
Content last modified: March 18, 2009
Written by Kurt Gron. Reviewed by Helena Fitch-Snyder.
Cite this page as:
Gron KJ. 2009 March 18. Primate Factsheets: Slow loris (Nycticebus) Conservation . . Accessed 2020 July 10.
The following references were used in the writing of this factsheet. To find current references for Nycticebus, search PrimateLit.
Ankel-Simons F. 2007. Primate anatomy, an introduction: third edition. San Diego: Elsevier. 724p.
Barrett E. 1981. The present distribution and status of the slow loris in peninsular Malaysia. Malays Appl Biol 10(2):205-11.
Brandon-Jones D, Eudey AA, Geissmann T, Groves CP, Melnick DJ, Morales JC, Shekelle M, Stewart CB. 2004. Asian primate classification. Int J Primatol 25(1):97-164.
Chen J-H, Pan D, Groves C, Wang Y-X, Narushima E, Fitch-Snyder H, Crow P, Thanh VN, Ryder O, Zhang H-W, Fu Y-X, Zhang Y-P. 2006. Molecular phylogeny of Nycticebus inferred from mitochondrial genes. Int J Primatol 27(4):1187-200.
Choudhury A. 2001. Primates in northeast India: an overview of their distribution and conservation status. ENVIS Bull 1(1):92-101.
Choudhury AU. 1992. The slow loris (Nycticebus coucang) in north-east India. Prim Rep 34:77-83.
Curtis DJ. 1995. Functional anatomy of the trunk musculature in the slow loris (Nycticebus coucang). Am J Phys Anth 97(4):367-79.
Daschbach NJ, Schein MW, Haines DE. 1982-1983. Cage-size effects on locomotor, grooming and agonistic behaviours of the slow loris, Nycticebus coucang (Primates, Lorisidae). Appl Anim Ethol 9(3-4):317-30.
Daschbach NJ, Schein MW, Haines DE. 1981. Vocalizations of the slow loris, Nycticebus coucang (Primates, Lorisidae). Int J Primatol 2(1):71-80.
Duckworth JW. 1994. Field sightings of the pygmy loris, Nycticebus pygmaeus, in Laos. Folia Primatol 63(2):99-101.
Ehrlich A. 1974. Infant development in two prosimian species: greater galago and slow loris. Dev Psychobiol 7(5):439-54.
Ehrlich A, Macbride L. 1989. Mother-infant interactions in captive slow lorises (Nycticebus coucang). Am J Primatol 19(4):217-28.
Ehrlich A, Musicant A. 1977. Social and individual behaviors in captive slow lorises. Behaviour 60(3-4):195-220.
Elliot O, Elliot M. 1967. Field notes on the slow loris in Malaya. J Mammal 48:497-8.
Fisher HS, Swaisgood RR, Fitch-Snyder H. 2003a. Countermarking by male pygmy lorises (Nycticebus pygmaeus): do females use odor cues to select mates with high competitive ability? Behav Ecol Sociobiol 53(2):123-30.
Fisher HS, Swaisgood RR, Fitch-Snyder H. 2003a. Odor familiarity and female preferences for males in a threatened primate, the pygmy loris Nycticebus pygmaeus: applications for genetic management of small populations. Naturwissenschaften 90(11):509-12.
Fitch-Snyder H, Ehrlich A. 2003. Mother-infant interactions in slow lorises (Nycticebus bengalensis) and pygmy lorises (Nycticebus pygmaeus). Folia Primatol 74(5-6):259-71.
Fitch-Snyder H, Thanh VN. 2002. A preliminary survey of lorises (Nycticebus spp.) in northern Vietnam. Asian Prim 8(1-2):1-3.
Fitch-Snyder H, Jurke M. 2003. Reproductive patterns in pygmy lorises (Nycticebus pygmaeus): behavioral and physiological correlates of gonadal activity. Zoo Biol 22(1):15-32.
Fooden J. 1991. Eastern limit of distribution of the slow loris, Nycticebus coucang. Intl J Primatol 12(3):287-90.
Gebo DL. 1987. Locomotor diversity in prosimian primates. Am J Primatol 13(3):271-81.
Groves CP. 2001. Primate taxonomy. Washington, D.C.:Smithsonian Institution. 350p.
Groves CP. 1971. Systematics of the genus Nycticebus. Proc. 3rd Int Cong Primatol, Zurich 1970 1:44-53.
Hagey LR, Fry BG, Fitch-Snyder H. 2007. Talking defensively, a dual use for the brachial gland exudates of slow and pygmy lorises. In: Gursky SL, Nekaris KAI, editors. Primate anti-predator strategies. New York:Springer. p253-72.
Haque MN, Siddiqi NA. 1988. Status of slow loris (Nycticebus coucang) in Bangladesh with some information on its food preferences. Tigerpaper 15(2):18-21.
Huynh DH. 1998. Ecology, biology and conservation status of prosimian species in Vietnam. Folia Primatol 69(suppl 1):101-8.
Ishida H, Jouffroy FK, Nakano Y. 1986. Comparative dynamics of pronograde and upside down horizontal quadrupedalism in the slow loris (Nycticebus coucang). In: Jouffroy FK, Stack MH, Niemitz C, editors. Gravity, posture and locomotion in primates. Firenze (IT):Il Sedicesimo. p209-20.
Izard MK, Weisenseel KA, Ange RL. 1988. Reproduction in the slow loris (Nycticebus coucang). Am J Primatol 16(4):331-9.
Kappeler PM. 1991. Patterns of sexual dimorphism in body weight among prosimian primates. Folia Primatol 57(3):132-46.
Khan MAR, Ahsan MF. 1986. The status of primates in Bangladesh and a description of their forest habitats. Prim Conserv 7:102-9.
Lan DY. 1999. Diversity and conservation of slow loris in Yunnan, China. Tigerpaper 26(4):12-5.
Malone N, Purnama AR, Wedana M, Fuentes A. 2002. Assessment of the sale of primates at Indonesian bird markets. Asian Prim 8(1-2):7-11.
Medhi R, Chetry D, Bhattacharjee PC. 2004. Slow loris (Nycticebus bengalensis) and its conservation in northeast India. Tigerpaper 31(3):6-9.
Nekaris KAI, Nijman V. 2007. CITES proposal highlights rarity of Asian nocturnal primates (Lorisidae: Nycticebus). Folia Primatol 78(4):211-4.
Nekaris KAI, Blackham GV, Nijman V. 2008. Conservation implications of low encounter rates of five nocturnal primate species (Nycticebus spp.) in Asia. Biodivers Conserv 17(4):733-47.
Nekaris A, Bearder SK. 2007. The Lorisiform primates of Asia and mainland Africa. In: Campbell CJ, Fuentes A, MacKinnon KC, Panger M, Bearder SK,editors. Primates in perspective. New York:Oxford U Pr. p24045.
Newell TG. 1971. Social encounters in two prosimian species: Galago crassicaudatus and Nycticebus coucang. Psychon Sci 24(3):128-30.
Nekaris KAI, Jaffe S. 2007. Unexpected diversity of slow lorises (Nycticebus spp.) within the Javan pet trade: implications for slow loris taxonomy. Contrib Zool 76(3):187-96.
Phipps M. 1992. Recent incidents involving illegal primate trade in Taiwan. Asian Prim 2(2):5-6.
Radhakrishna S, Goswami AB, Sinha A. 2006. Distribution and conservation of Nycticebus bengalensis in Northeastern India. Int J Primatol 27(4):971-82.
Rasmussen DT. 1986. Life history and behavior of slow lorises and slender lorises: implications for the lorisine-galagine divergence. PhD dissertation, Duke University. 190p.
Ravosa MJ. 1998. Cranial allometry and geographic variation in slow lorises (Nycticebus). Am J Primatol 45(3):225-43.
Rigel EP. 2004. Analysis of Lorisidae taxonomy using postcranial skeletal material. MA thesis, Georgia State University.
Schulze H, Groves CP. 2004. Asian lorises: taxonomic problems caused by illegal trade. In: Nadler T, Streicher U, Long HT, editors. Conservation of primates in Vietnam. Hanoi (VN): Frankfurt Zoological Society. p33-6.
Streicher U. 2004a. Aspects of ecology and conservation of the pygmy loris (Nycticebus pygmaeus) in Vietnam. PhD dissertation, Ludwig-Maximilians Universität, Munich (DE).
Streicher U. 2004. Confiscated primates-healths aspects and long-term placement options. In: Nadler T, Streicher U, Long HT, editors. Conservation of primates in Vietnam. Frankfurt(DE): Frankfurt Zool Soc. p154-60.
Streicher U, Schulze H, Plesker R, Vornefeld B. 2002. A conservation and health database for lorises and pottos. Prim Rep 63:33-9.
Striecher U. 2007. Morphological data of pygmy lorises (Nycticebus pygmaeus). Vietnam J Primatol 1(1):67-74.
Streicher U. 2004b. Seasonal changes in colouration and fur patterns in the pygmy loris (Nycticebus pygmaeus). In: Nadler T, Streicher U, Ha Thang Long, editors. Conservation of primates in Vietnam. Frankfurt (DE): Frankfurt Zoological Soc. p29-32.
Tan CL, Drake JH. 2001. Evidence of tree gouging and exudates eating in pygmy slow lorises (Nycticebus pygmaeus). Folia Primatol 72(1):37-9.
Tenaza R, Fitch H. 1984. The slow loris. Zoonooz 57(4):10-2.
Utami SS, van Hooff JARAM. 1997. Meat-eating by adult female Sumatran orangutans (Pongo pygmaeus abelii). Am J Primatol 43(2):159-65.
Weigl R. 2005. Longevity of mammals in captivity; from the living collections of the world. Stuttgart (DE): E. Schweizerbartsche. 214p.
Wiens F. 2002. Behavior and ecology of wild slow lorises (Nycticebus coucang): social organization, infant care system, and diet. PhD dissertation, University of Bayreuth.
Wiens F, Zitzmann A, Hussein NA. 2006. Fast food for slow lorises: is low metabolism related to secondary compounds in high-energy plant diet? J Mammal 87(4):790-8.
Wiens F, Zitzmann A. 1999. Predation on a wild slow loris (Nycticebus coucang) by a reticulated python (Python reticulates). Folia Primatol 70(6):362-4.
Wiens F, Zitzmann A. 2003a. Social dependence of infant slow lorises to learn diet. Int J Primatol 24(5):1007-21.
Wiens F, Zitzmann A. 2003b. Social structure of the solitary slow loris Nycticebus coucang (Lorisidae). J Zool Lond 261(1):35-46.
Weisenseel KA, Izard MK, Nash LT, Ange RL, Poorman-Allen P. A comparison of reproduction in two species of Nycticebus. Folia Primatol 69(suppl 1):321-4.
Wilde H. 1972. Anaphylactic shock following bite by a “slow loris,” Nycticebus coucang. Am J Trop Med Hyg 21(5):592-4.
Zhang Y-Z, Wang S, Quan G-Q. 1981. On the geographical distribution of primates in China. J Hum Evol 10:215-26.
Zimmermann E. 1981. First record of ultrasound in two prosimian species. Naturwissenschaften 68:531-2.
Zimmermann E. 1989. Reproduction, physical growth and behavioral development in slow loris (Nycticebus coucang, Lorisidae). Hum Evol 4(2-3):171-9.
Zimmermann E. 1985. Vocalizations and associated behaviours in adult slow loris (Nycticebus coucang). Folia Primatol 44(1):52-64.
Content last modified: March 18, 2009
Photo: Andrew Johns
Photo: J. R. Mackinnon
Photo: Marilyn Cole
Photo: Marilyn Cole
Primate Info Net (PIN) is maintained by the Wisconsin National Primate Research Center (WNPRC) at the University of Wisconsin-Madison, with countless grants and contributions from others over time. PIN is an ever-growing community effort: if you’d like to contribute, or have questions, please don’t hesitate to contact us.