Nycticebus pygmaeuspygmy slow loris

Geographic Range

Pygmy slow lorises, Nycticebus pygmaeus, are found in Vietnam, Laos, eastern Cambodia, and neighboring regions of southern China (southeast Yunnan province). It is unclear whether populations in China are native or introduced. (Streicher, et al., 2008)


Pygmy slow lorises reside in rainforests and degraded habitats as well as bamboo thickets in Vietnam and evergreen forest in Laos. They have been observed at altitudes as great as 1500 m.

Locals in the Mondulkiri province of Cambodia suggest that pygmy slow lorises prefer thick, complex forested areas with bamboo to dry dipterocarp forest, and observations confirm their preference of mixed deciduous to semi-evergreen forests. Individuals of this species are usually seen at heights of 3 to 12 m in the canopy. (Ratajszczak, 1998; Starr, et al., 2011)

  • Range elevation
    1500 (high) m
    4921.26 (high) ft

Physical Description

Zoologist J.L. Harrison describes pygmy slow lorises as "rather like a child's teddy-bear." They have thick light brown to deep reddish brown fur with a white or gray underside. Individuals have a unique pattern of lighter and darker colored markings on their face, which commonly include circles around the eyes and dorsal stripes starting at their crown and continuing down their back. During the winter, these markings become more prominent, and they acquire silver tips or "frosting." This seasonal coloration is thought to camouflage and protect the animals, as, during the winter, they must sit in exposed areas such as dense scrub or in the upper branches of trees that lack foliage.

Like other strepsirhine primates and members of the family Lorisidae, pygmy slow lorises have: forward-facing eyes with stereoscopic vision; a rhinarium, the moist naked surface around the nostrils; a tapetum lucidum, the reflective layer in the eye that improves night vision; a split upper lip; nails on all digits except for a grooming claw on the second digit of their feet; a dental formula of with the lower incisors and canines forming a toothcomb; no tail; and reduced second digits on their hands.

Pygmy slow lorises and Bengal slow lorises evolved from a common ancestor and are similiar in appearance. The smaller body size in pygmy slow lorises is thought to be the result of character displacement, the accentuation of differences between similar species that share the same geographic distribution.

Pygmy slow lorises measure 15 to 25 cm in length and weigh from 120 to over 500 g (average 400 g). Males are generally larger than females. Members of this species can retard their growth if environmental conditions are not favorable. If their diet is restricted, they lose their juvenile fur and attain adult dentition before attaining adult size.

Pygmy slow lorises produce a toxin from modified sweat glands located near their elbows. They have been observed licking theses glands when alarmed. Their bite can be dangerous to humans; the only account of a pygmy slow loris biting a human resulted in an adult woman entering anaphylactic shock. (Fleagle, 1999; Harrison, 1955; Kalimullah, et al., 2008; Ravosa, 1998; Streicher, 2004)

  • Sexual Dimorphism
  • male larger
  • Range mass
    120 to 500+ g
    4.23 to oz
  • Average mass
    400 g
    14.10 oz
  • Range length
    15 to 25 cm
    5.91 to 9.84 in


Although mating has been observed in captivity, little to nothing is known about mating of pygmy slow lorises in the wild.

Female pygmy slow lorises enter estrus between July and October. During this period, the female vagina and male testes become enlarged. Behavior also differs during this period; females are more likely to approach others and engage in lunging, while males are more likely to sniff and lick a female's genitals and mount them.

Pygmy slow lorises are polygynous. A male's territory typically includes several females with whom he mates. Males and females communicate with one another through whistles. Olfactory cues are also used to find mates. Males spread their scent through urination, and males thus produce more urine than females. Males that spread their scent over a large area have a competitive advantage, because marking territory is an indication of health, persistence, and energy. Females prefer males with a familiar odor to males they have not previously encountered, which may be related to infrequent contact between the sexes. (Fisher, et al., 2003; Fitch-Snyder, et al., 1999; Streicher, 2004)

Pygmy slow lorises reproduce once every 12 to 18 months. Females enter estrus between July and October. After about 6 months, females give birth to 1 to 2 offspring, generally during the winter months. Twinning is common among this species. Birthing occurs in the open, and infants are born fully formed with fur and open eyes. Offspring are nursed for an average of 4.5 months, though in some cases weaning may take as long as 8 months. Females reach sexual maturity at about 9 months of age, while males reach sexual maturity at 18 to 20 months of age. ("Loris, Lesser Slow", 2011; "Pygmy Slow Loris", 2011; Nijman and Nekaris, 2010; Ratajszczak, 1998; Streicher, 2004)

  • Breeding interval
    Pygmy slow lorises breed once every 12 to 18 months.
  • Breeding season
    Pygmy slow lorises generally breed from end of July to the beginning of October.
  • Range number of offspring
    1 to 2
  • Average number of offspring
  • Average gestation period
    6 months
  • Average gestation period
    188 days
  • Range weaning age
    4 to 8 months
  • Average weaning age
    4.5 months
  • Average age at sexual or reproductive maturity (female)
    9 months
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    273 days
  • Range age at sexual or reproductive maturity (male)
    18 to 20 months

Immediately after birth, pygmy slow lorises cling to their mother's underside. Later, mothers exhibit "parking" behavior, leaving their infants in a safe location while they leave to forage for food. Without the burden of a dependent, mothers can more efficiently gather food for themselves and their offspring.

Individuals in the San Diego Zoo have a similiar parenting style to that of other species of slow lorises. However, pygmy slow lorises spend more time in close proximity to their young, tending to huddle, sit or stand within 0.3 m of their offspring more than other species. Mothers and infants primarily establish closeness through passive ventral contact. Although mothers do not appear to directly defend their young, they tolerate the following behavior of their young as they get older. As infants age, they engage more often in adult social behaviors such as grooming and play, and less often in huddling and ventral contact. ("Pygmy Slow Loris", 2011; Fitch-Snyder and Ehrlich, 2003)

  • Parental Investment
  • female parental care
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female


In captivity, pygmy slow lorises are capable of reproduction as old as 14 years of age. They have been known to live 20 years in captivity. ("Pygmy Slow Loris", 2011; Ratajszczak, 1998)

  • Range lifespan
    Status: captivity
    20 (high) years
  • Average lifespan
    Status: captivity
    17.1 years


Pygmy slow lorises are nocturnal, arboreal quadrupeds with grasping hands and feet. They walk along branches hand over foot, stretching from one branch to the next. Their strong grip allows them to hang by their feet and gather food with both hands or to stand bipedally then throw their upper body forward to pounce on prey. Pygmy slow lorises almost exclusively remain in trees, except on rare occasions in response to potential predators.

Pygmy slow lorises are thought to move almost constantly during the night hours of warmer months. Members of this species are commonly referred to as "slow lorises" due to the speed of their movement, but observations made at the Duke Lemur Center indicate that their movement is actually faster than other species of slow loris.

During cold winter months, pygmy slow lorises are capable of entering a state of torpor and living off their fat reserves. They reduce their activity, lower their metabolic rate and body temperature, and do not forage. This hibernation-like behavior is observed both in the wild and in captivity.

Because pygmy slow lorises have only rarely been studied in the wild, many aspects of their behavior are still unknown. While they are generally considered solitary, pygmy slow lorises are occasionally characterized as "gregarious" due to their mating behavior. A species that spends over 50% of its time with conspecifics is classified as gregarious. However, currently no scientific study has confirmed this potentially gregarious nature. The territory of one male often overlaps with the territory of several females, leading to polygynous mating behavior and more frequent social behavior in males.

Studies of Sunda slow lorises, a closely related species, suggest slow lorises maintain friendly relationships with conspecifics that share their home range, forming "spatial groups." It is unclear how they might benefit from these social groupings, as slow lorises rely on crypsis for protection from predators, do not assist others in finding food, and do not engage in alloparenting. ("Nycticebus pygmaeus Bonhote, 1907", 2011; "Pygmy Slow Loris", 2011; Nekaris, et al., 2008; Ratajszczak, 1998; Wiens and Zitzmann, 2003)

Home Range

The home range of pygmy slow lorises is as yet unknown.

In Sunda slow lorises, type of habitat affects the size of a home range, which is highly variable. There is broad overlap between ranges of Sunda slow lorises. (Wiens and Zitzmann, 2003)

Communication and Perception

Pygmy slow lorises utilize a variety of verbal communications. When disturbed, they growl and hiss. They issue a rising tone during general contact and may whistle to the opposite sex during estrus. Mothers softly chirp to their infants, who respond with rapid clicks and squeaks when they are in distress.

Males mark their territory with urine, which also affects mating behavior (See Reproduction: Mating Systems). ("Loris, Lesser Slow", 2011; Fisher, et al., 2003)

Food Habits

Reports from local people of Cambodia suggest pygmy slow lorises eat mostly termites, tree parts, fruit, and bamboo. Though surveys confirm they do eat this variety of foods, the absolute preference for termites over the other foods is not clear. There is also great debate over the degree of insectivory in this species. Some suggest that insects make up approximately 33% of their diet (Duke Lemur Center 2011), while others state that they are frugivorous (Fleagle 1999). Although early accounts of the species (Harrison 1955) indicate that members of this species eat insects, lizards, eggs, and "anything edible" in addition to fruit, recent studies do not corroborate these observations.

At the Endangered Primate Rescue Center, captive pygmy slow lorises are offered fruit, vegetables, boiled eggs, milk powder, and insects, and the insects are the most readily accepted food item. However, this finding cannot be used to assert they are not frugivorous, because the cultivated fruit offered to them may not be what they prefer in the wild.

Captive animals also gouge fresh tree branches, indicating a preference for exudates. They have been observed licking Saraca dives, Sapindus and Vernicia montana trees for periods between 1 and 20 minutes. Pygmy slow loris scratch and break the bark of other species of trees, feeding on the gum.

Pygmy slow lorises develop fat stores by increasing their feeding and choosing more energy-rich foods in the last few weeks of autumn. These fat stores are useful during the food scarce winter months.

Despite the high-sugar diet and small body mass of close relatives Sunda slow lorises, they have a very low metabolism. This may be due to a need to detoxify the toxic secondary compounds in their food matter. ("Pygmy Slow Loris", 2011; Fleagle, 1999; Harrison, 1955; Ratajszczak, 1998; Starr, et al., 2011; Streicher, 2004; Wiens, et al., 2006)

  • Animal Foods
  • eggs
  • insects
  • Plant Foods
  • fruit
  • nectar
  • flowers
  • sap or other plant fluids
  • Other Foods
  • fungus


Little is known regarding non-human predation of pygmy slow lorises. Although predation by Sumatran orangutans has been reported, the habitats of Sumatran orangutans and pygmy slow lorises do not overlap. Predation by reticulated pythons has also been reported. Pygmy slow lorises are cryptic, blending in well with their surroundings. This may contribute to low non-human predation rates.

Humans are the primary predators of pygmy slow lorises. Their prevalence in Cambodian and Vietnamese markets testifies to the intense hunting pressure on this species. Camobodian locals report hunting pygmy slow loris as a "non-target species," suggesting that the rate of hunting is not affected by abundance and will continue even as these animals become more scarce.

Pygmy slow lorises are easy prey because of their tapetum lucidum, the reflective layer in the eye that improves night vision, which glows when a spotlight is shone in their direction and by some accounts incapacitates them. This makes this species an easy target for night hunters. (Starr, et al., 2011; Streicher, 2004; Wiens and Zitzmann, 1999)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Because they may consume a considerable amount of fruit, pygmy slow lorises may play a role in seed dispersal.

In Polish zoos, oocytes of the parasitic protozoan Cryptosporidium, "crypto", have been found in the feces of pygmy slow lorises, indicating infection. Crypto is not typically studied in non-domesticated non-human primates, and little information is available regarding its prevalence.

An outbreak of ocular oxyspirurosis in a Moscow zoo was attributed to a pygmy slow loris from Vietnam. This condition is caused by the parasitic nematode Oxyspirura.

Pygmy slow lorises also act as hosts to some protozoan parasites (Entamoeba histoytica, Blantidium coli, Toxoplasma gondii, Giardia, Blastocystis hominis) and nematodes (Enterobius, Oxyrus, Trichuris). (Fayer and Xiao, 2008; Ivanova, et al., 2007; Schulze, 2005)

Commensal/Parasitic Species
  • Cryptosporidium
  • Oxyspirura
  • Entamoeba histoytica
  • Blantidium coli
  • Toxoplasma gondii
  • Giardia
  • Blastocystis hominis
  • Enterobius
  • Oxyrus
  • Trichuris

Economic Importance for Humans: Positive

Pygmy slow lorises are commonly used in medicines in Cambodia. In Phnom Penh, they are found in local markets roasted, dried, and made into pre-mixed medicines with rice-wine, alcohol, honey, or charcoal. Doctors of traditional medicine reported in questionnaires that these medicines are primarily used to treat "women after childbirth, stomach problems, wounds, broken bones, and sexually transmitted diseases" (Starr et al. 2010). In the 1950s from Burma to Borneo, the fur of slow lorises was used to dress wounds and cuts because of its blood clotting properties, and it may still be used as such in some localities. Some researchers attribute the popularity of loris medicine to the lack of access to or education about biomedical alternatives and high levels of poverty.

Due to increased protection of this species, market price is increasing. Veteran hunters able to distinguish different species of loris and know species distributions in local forests yield high profits. Trade is driven by wealthy city dwellers who are able and willing to pay rural hunters for their illegal product.

Live trade of slow lorises occurs in high levels in the Mondulkiri, Ratanakiri, and Phnom Penh provinces of Cambodia. As many as 204 lorises were found in a single store in Phnom Penh. Slow lorises are the most popular pets that are listed on CITES Appendix I. They are primarily traded in Borneo, Java, Sumatra, and the surrounding islands. Live trade of slow lorises most commonly affects Sunda slow lorises, Bornean slow lorises, and Javan slow lorises, but traders do not distinguish among species, and other slow lorises such as pygmy slow lorises are sometimes traded as well. This lack of differentiation among species leads to hybridization, improper care and health problems, as well as reintroduction of confiscated animals into improper habitat. (Dasgupta, et al., 2005; Harrison, 1955; Nekaris and Jaffe, 2007; Nekaris, et al., 2010; Starr, et al., 2010)

Economic Importance for Humans: Negative

Pygmy slow lorises may produce a toxin from modified sweat glands located near their elbows. They have a toxic bite which is dangerous to humans. The only account of a pygmy slow loris biting a human resulted in the adult woman entering anaphylactic shock. (Wiens, et al., 2006)

  • Negative Impacts
  • injures humans

Conservation Status

Pygmy slow lorises are considered threatened by the IUCN. Populations decreased by 30% between 1984 and 2008, and they continue to decline.

Populations of pygmy slow lorises drastically declined during the Vietnam War, as bombing, land clearing by Rome plows, and use of Agent Orange (2,4,5-T), other defoliants, and napalm destroyed the majority of their native habitat in Vietnam, Laos, and Cambodia. Bombing is estimated to have damaged 40% of Vietnamese forests, and herbicides affected 43% of the cultivated area. Prior to the Vietnam War, broad-leafed tropical forests with stands of bamboo and mangroves covered approximately one-half of the land area in these countries.

The use of pygmy slow lorises in traditional medicine, as well as the reluctance of consumers and doctors of traditional medicine to use alternatives, threatens the future of this species.

Lorises are frequently killed by logging and slash and burn agriculture. If they are not killed in the fire, they face habitat destruction, which may lead to their eventual disappearance from the area. The resulting fragmentation of forests further threatens the species.

Pygmy slow lorises were listed in Appendix II by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) in February 1977. They were promoted to Appendix I in September 2007, which indicates trade of this species has not been properly controlled in the last few decades.

Although trade is restricted and capture and transport of pygmy slow lorises is illegal in all countries in their range, their small size makes slow lorises easy to traffic in boxes, baskets, and sacks from country to country. This process is physically stressful for the animals and also threatens their health. Rescue centers have been developed for confiscated slow lorises, but mortality rates remain high. These deaths are attributed to trauma, disease, and atypically close proximity to conspecifics. (Ratajszczak, 1998; Starr, et al., 2010; Streicher, et al., 2008; Streicher, 2004; "UNEP-WCMC Species Database: CITES-Listed Species", 2011)

Other Comments

In Vietnamese folklore, pygmy slow lorises are called "khi gio", or "monkeys that move with the wind." They portend bad fortune and are used for black magic. (Streicher, 2004)


Margaret Gray (author), Yale University, Eric Sargis (editor), Yale University, Gail McCormick (editor), Animal Diversity Web Staff.



uses sound to communicate


Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


an animal that mainly eats meat


uses smells or other chemicals to communicate


having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.


a substance used for the diagnosis, cure, mitigation, treatment, or prevention of disease


animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females


forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.


an animal that mainly eats fruit


An animal that eats mainly plants or parts of plants.


the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.


An animal that eats mainly insects or spiders.


having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.


active during the night


an animal that mainly eats all kinds of things, including plants and animals


found in the oriental region of the world. In other words, India and southeast Asia.

World Map

pet trade

the business of buying and selling animals for people to keep in their homes as pets.


an animal which has a substance capable of killing, injuring, or impairing other animals through its chemical action (for example, the skin of poison dart frogs).


having more than one female as a mate at one time


rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

seasonal breeding

breeding is confined to a particular season


reproduction that includes combining the genetic contribution of two individuals, a male and a female


lives alone


uses touch to communicate


defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement


The term is used in the 1994 IUCN Red List of Threatened Animals to refer collectively to species categorized as Endangered (E), Vulnerable (V), Rare (R), Indeterminate (I), or Insufficiently Known (K) and in the 1996 IUCN Red List of Threatened Animals to refer collectively to species categorized as Critically Endangered (CR), Endangered (EN), or Vulnerable (VU).


the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.


an animal which has an organ capable of injecting a poisonous substance into a wound (for example, scorpions, jellyfish, and rattlesnakes).


uses sight to communicate


reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.


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