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Federal restrictions apply

Sunda slow loris

Nycticebus coucang

Also known as Cu Lan, Slow Loris

Mammals › Monkeys, lemurs and apes (Primates) › Lorisidae (Lorises and pottos)

The Sunda slow loris (Nycticebus coucang), or greater slow loris, is a strepsirrhine primate and a species of slow loris native to Indonesia, West Malaysia, southern Thailand and Singapore.

Zoos & aquariums

Experience: Expert / facility

FamilyLorises and pottos

Record lifespan26.5 years

Adult weight32.5 oz

Kept byZoos & aquariums

Care at a glance

Species-specific values

Values researched for this exact species. Where they differ from the group guide below, follow these. Air, surface and water temperatures are listed separately, and each source is kept as published rather than averaged.

Air temperature	66–82 °F (19–28 °C) EAZA captive recommendation, separate from wild seasonal observations.	308
Relative humidity	70–80 % RH	308
Minimum enclosure requirements	length greater than: 5; width greater than: 2; height greater than: 2.5; area greater than: 15 Meet all requirements; area is an independent constraint.	308
Diet gum arabic fraction	10–20 % food weight EAZA food-category range; formulate the complete ration separately.	308
Diet fruit and nectar fraction	0–5 % food weight Enrichment allowance.	308
Reported captive lifespan maximum	24 years	308

Warnings

Mostly kept by zoos, public aquariums, sanctuaries or licensed facilities. The guide below describes professional husbandry so you can understand the animal, not as encouragement to keep one privately.

Federal legal status: Federal restrictions apply. See the federal legal snapshot and check your state rules before getting one.

Care guide

Group care guide

Bushbabies and lorises

Applies to most species in this group. Habitat: African and Asian forests. Individual species can differ, so compare with the species numbers above and the linked sources.

Housing & setup

Nocturnal, enriched enclosures with dense branches.

Sources 135 308

Diet

Separate bushbaby and slow-loris diets. For slow lorises, provide gum, insects, appropriate vegetables and formulated components; fruit and nectar are limited enrichment, not staples.

Sources 135 308

Health watch

Slow lorises have a venomous bite and are CITES Appendix I; illegal pet trade harms wild populations.

Sources 135 308

Understanding the animal

About this animal

It measures 27 to 38 cm (11 to 15 in) from head to tail and weighs between 599 and 685 g (21.1 and 24.2 oz). Like other slow lorises, it has a wet nose (rhinarium), a round head, small ears hidden in thick fur, a flat face, large eyes and a vestigial tail.

Quoted from the Wikipedia article “Sunda slow loris” (CC BY-SA 4.0) 174

In the wild

Quoted from the matching sections of reputable sources for this exact species. Specialist databases are used first; Wikipedia (community-edited, CC BY-SA 4.0) only fills gaps. Other sources are short credited quotes.

Overview	The Sunda slow loris (Nycticebus coucang), or greater slow loris, is a strepsirrhine primate and a species of slow loris native to Indonesia, West Malaysia, southern Thailand and Singapore. It measures 27 to 38 cm from head to tail and weighs between 599 and 685 g. Like other slow lorises, it has a wet nose (rhinarium), a round head, small ears hidden in thick fur, a flat face, large eyes and a vestigial tail. The Sunda slow loris is nocturnal and arboreal, typically occurring in evergreen forests. — Wikipedia (community-edited)
Where it lives	Sunda slow lorises mainly inhabit primary and secondary tropical lowland forests. — Animal Diversity Web
Social life and communication	Adults exhibit eight distinct calls of one of two types: contact calls (whistles, short keckers) and aggressive or defensive calls (long keckers, grunts, snarls, screams). — Animal Diversity Web
Behavior	Sunda slow lorises move slowly through trees on all four limbs, typically with three limbs attached to support at any given time. — Animal Diversity Web
Reproduction	Males track females in estrus; however, females initiate the act of copulation. — Animal Diversity Web
Lifespan	In the wild, this species average life span is 20 years, including one individual that survived 22 years. — Animal Diversity Web
Appearance and size	Sunda slow lorises range in length from 27 to 38 centimeters and weight from 599 to 685 grams. — Animal Diversity Web
History and naming	The common name, Sunda slow loris, refers to the Sunda Islands, a group of islands in the western part of the Malay Archipelago where it is found. Another common name for the species is the greater slow loris. The specific name, coucang, derives from kukang, its common name in Indonesia. — Wikipedia (community-edited)

Native climate (measured)

Warm-season highs	about 89°F (up to 93°F in the hottest sampled areas)
Cool-season lows	about 71°F (down to 64°F in the coldest sampled areas)
Average temperature	73–82°F across sampled records
Relative humidity	80–84% on average (driest month about 79%)
Rainfall	about 2402 mm a year, spread fairly evenly

Measured at 11 wild occurrence records sampled against WorldClim 2.1 climate data (1970–2000 averages). Air conditions in the range are ecological context, not enclosure settings: microhabitats such as burrows, leaf litter or basking rocks can be cooler, warmer or more humid.

Profile

Researched for this exact species. Sources are listed under In the wild above.

History

The common name, Sunda slow loris, refers to the Sunda Islands, a group of islands in the western part of the Malay Archipelago where it is found. Another common name for the species is the greater slow loris. The specific name, coucang, derives from kukang, its common name in Indonesia.

Data and studies

Researched care notes

Findings checked against veterinary, zoo, welfare, keeper and peer-reviewed sources. Air, basking-surface and water temperatures are kept separate, and where sources disagree both are shown. “Study” notes report what a paper measured, not a universal rule.

Slow Lorises (group)

Researched for this genus; applies to its species unless a species note says otherwise.

Provide dense usable horizontal branches or bamboo, leafy retreats, and nest boxes with more than one exit.¹
The guideline favours exudate/gum and invertebrate feeding models over historical fruit-heavy or dog/cat-food diets.¹
Social organisation varies by species and individual; managed pairs or families require aggression monitoring.¹

Slow lorises

The numbers

Each bar is what one source reports. Where several sources weigh in, the dashed gold band marks their average.

Maximum recorded lifespan

Highest reported26.5years

AnAge 16225.8

Myhrvold et al. 16326.5

Longest recorded lifespan reported by each database; typical lifespans are usually shorter. The AnAge record comes from an animal in human care.

Typical adult weight

Average of sources32.5oz

AnAge 16231.4

Myhrvold et al. 16333.6

Average adult body mass in each database (FishBase gives the maximum recorded weight).

Litter size

Average of sources1young

AnAge 1621

Myhrvold et al. 1631

Average per litter or clutch.

Gestation

Average of sources189days

AnAge 162188

Myhrvold et al. 163190

Female maturity

Average of sources19.6months

AnAge 16219

Myhrvold et al. 16320.3

Veterinary & husbandry research

Reproduction in the slow loris (Nycticebus coucang) Izard MK et al., American journal of primatology 1988
Positional and activity behavior in a captive slow loris: A quantitative assessment Glassman DM et al., American journal of primatology 1984
Mother-infant interactions in captive slow lorises (Nycticebus coucang) Ehrlich A et al., American journal of primatology 1989
Redescription of Pterygodermatites (Mesopectines) nycticebi (Mönnig, 1920) (Nematoda: Rictulariidae), a parasite of slow loris Nycticebus coucang (Mammalia: Primates) Ikeda Y et al., Folia parasitologica 2003

Peer-reviewed papers that mention this species alongside captivity, zoos, veterinary care or aquaculture. Some cover several species or mention it only in passing, so check the abstract. See all 7 on PubMed → 170

Federal legal snapshot

Federal restrictions apply

CITES Appendix I. Appendix I: commercial international trade in wild-caught animals is banned; international movement needs both import and export permits. Buying captive-bred animals within the U.S. isn't restricted by CITES (other federal or state laws may apply). 173 186
CDC primate import rule. Nonhuman primates can be imported only by CDC-registered importers for science, education or exhibition, never as pets. Most states also ban or tightly restrict pet primates. 188
USDA Animal Welfare Act. Keeping a pet for yourself doesn't need a federal license. Dealers (including many breeders who sell wholesale or sight-unseen) and exhibitors (including encounters and paid programs) generally need a USDA license and inspections; some small-scale breeders and retail sellers are exempt. 184

State law decides most of it. Each state sets its own permits and bans for exotic, native, venomous and dangerous animals, and cities and counties can be stricter. Find your state agency →

Animal Welfare Act standards

Nonhuman primates (Subpart D). Applies to USDA-licensed or registered dealers, exhibitors (including encounters and paid programs) and research facilities. Private pet owners are not covered. These are legal minimums, not best care; the species care on this page goes further.

Facilities must document and follow an environment enhancement plan for psychological well-being, directed by the attending veterinarian. §3.81
Social needs: species that live in groups in nature must have provision for social housing; individually housed primates must be able to see and hear their own or a compatible species. §3.81
Enrichment must let them express non-injurious species-typical behavior: perches, swings, objects to manipulate, varied food, foraging or task-oriented feeding, and interaction with familiar caregivers. §3.81
Special attention is required for infants and young juveniles, animals showing psychological distress, those used in research, great apes over 110 lb and individually housed animals. §3.81
Minimum enclosure space is set by the species' typical weight; perches and swings don't count toward it unless the space beneath can be comfortably used. §3.80

Source: 9 CFR Part 3, current eCFR text (USDA APHIS Animal Care).

Kept in captivity?

Every species on this site needs evidence that people actually keep it. For this one:

Included in our hand-checked list of animals kept as pets, livestock or in zoos
AnAge has a longevity record from an animal in captivity
18 iNaturalist observations of captive animals

Sources for this sheet

AnAge: The Animal Ageing and Longevity Database (Human Ageing Genomic Resources) Peer-reviewed researchCurated, referenced longevity and life-history records for thousands of species; maximum lifespans are often from zoo animals.
Myhrvold et al. (2015). An amniote life-history database. Ecology 96: 3109 Peer-reviewed researchPeer-reviewed compilation of life-history data for over 21,000 birds, mammals and reptiles.
Species+ (UNEP-WCMC and the CITES Secretariat) Zoo, university or veterinaryThe official database of species listed under CITES.
USFWS International Affairs: CITES Zoo, university or veterinaryFederal agency that issues CITES permits.
CDC: Bringing an animal into the United States Zoo, university or veterinaryFederal rules on importing animals that can carry human disease.
9 CFR 2.1: Animal Welfare Act licensing (USDA) Zoo, university or veterinaryWho needs a USDA license to breed, sell or exhibit animals.
Merck Veterinary Manual: Overview of nonhuman primates Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
EAZA Best Practice Guidelines — Nycticebus species (2022) Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
GBIF Backbone Taxonomy (Global Biodiversity Information Facility) Peer-reviewed researchInternational scientific taxonomy used here for classification.
Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
PubMed (U.S. National Library of Medicine) Peer-reviewed researchIndex of peer-reviewed veterinary, zoo and husbandry research.
iNaturalist (captive observations) Community referenceCommunity observation platform run by the California Academy of Sciences and National Geographic; observations marked captive show animals living in homes, zoos and aquariums.