SLOW LORISES
Slow lorises are less common than slender lorises. The belong to the Genus Nycticebus. The subspecies are:
Bangka slow loris (Nycticebus bancanus)
Bengal slow loris (Nycticebus bengalensis)
Bornean slow loris (Nycticebus borneanus)
Sunda slow loris (Nycticebus coucang)
Javan slow loris (Nycticebus javanicus)
Kayan River slow loris (Nycticebus kayan)
Philippine slow loris (Nycticebus menagensis)
Sumatran slow loris (Nycticebus hilleri)
Nycticebus linglom (fossil, Miocene)
Sunda slow lorises are sold as exotic pets throughout Southeast Asia and more recently in the western world. They are the most commonly traded of the protected primates in Southeast Asia. Their body parts have long been used in traditional medicines. Their fur is reported to heal wounds, their flesh is used to cure epilepsy, their eyes are used in love potions and their meat is reported to cure asthma and stomach problems. In December 2022 a Javan slow loris was released in a National Park of Mount Salak by International Animal Rescue (IAR) which have confiscated lorises from individuals and markets which illegally sell them as pets in West Java, Indonesia. [Source: Taiyler Simone Mitchell, Business Insider December 24, 2022]
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Slow Loris and Cobra Mimicry and Poisons
Although they look cute and cuddly they have a darker side. They mimic cobras and have a venomous bite that can cause anaphylactic shock or even death in humans. Such bites are very rare and often perhaps the person that got bitten deserved it. It may also be possible for humans to get sick from eating loris meat.
Slow loris elbows contain glands that exude oils, which are licked and spread by the individual to communicate position and status. This species also uses perineal rubbing to deposit urine combined with the oil, from a separate gland on their anus. When locating the scent of another, the individual will usually rub its face on the surface where the scent was found. The oil is poisonous, with enough power to kill an adult human if not treated properly. Stressed individuals may grin, baring their teeth to present aggression or fear, but they may also grin during play. [Source: Paul Peña, Animal Diversity Web (ADW) /=]
Alissa Zhu, Popular Science Its big doe eyes, furry face, and tiny grasping hands are a deceptive mask for its deadly nature. Slow lorises are the only known venomous primate, secreting toxins from a gland located along the crook of their inner arms. When threatened, a slow loris will hiss and retreat into a defensive posture with its paws clasped on top of its head. In this position, the slow loris’s upraised arms combined with dark markings on its face look remarkably like the expanded hood of an angered Spectacled cobra. To add to the effect, slow lorises can even undulate in a serpentine fashion. This unusual movement is made possible by an extra vertebra in their spines. The defense posture also allows slow lorises to suck the venom from their armpits and strike quickly. The bites of these tiny primates have caused anaphylactic shock and even death in humans.[Source:Alissa Zhu, Popular Science, October 13, 2014]
An article published in October 2014 in the Journal of Venomous Animals and Toxins including Tropical Diseases suggested slow lorises adopted serpentine markings and movements as defense mechanisms. loris When threatened, slow lorises retreat into a defensive posture that mimics cobras. For eight million years, slow lorises and cobras have coexisted in the same parts of Asia. Together, they weathered through drastic climate changes, which may have forced the traditionally tropical forest dwelling slow loris to adapt to an open savannah-like environment by mimicking venomous snakes.
In 1905, naturalist John Still wrote one of the first accounts of coming across a slow loris and mistaking it for a cobra in Sri Lanka. “I got up and took a stick, for I thought that a cobra might be attacking my Loris, who was not in his cage, but only tethered to the top of it. The sound came from my room, where, although it was dusk, there was plenty of light to kill a snake. As I went into the room I looked at the cage, which was on the floor, and on the top of it I saw the outline of a cobra sitting up with hood expanded, and threatening a cat who crouched about six feet away. This was the Loris, who, with his arms and shoulders hunched up, was a sufficiently good imitation of a cobra to take me in, as he swayed on his long legs, and every now and then let out a perfect cobra's hiss. As I have said, it was dusk at the time, but the Loris is nocturnal, so that his expedient would rarely be required except in the dusk or dark; and the sound was a perfect imitation. I may mention that I have kept snakes, including a cobra, and am therefore the less likely to be easily deceived by a bad imitation.
Sunda Slow Lorises
Red — Pygmy Slow Loris (Nycticebus pygmaeus)
Blue — Bengal Slow Loris (Nycticebus bengalensis)
Purple — Sunda Slow Loris (Nycticebus coucang).
Sunda slow lorises (Nycticebus coucang) live mainly in Indonesia (Sumatra, Batam and Galang in the Riau Archipelago, and Pulau Tebingtinggi and Bunguran in the North Natuna Islands), Malaysia (on the Peninsula and the island of Pulau Tioman), the southern peninsular area of Thailand (from the Isthmus of Kra southward) and throughout Singapore. [Source: Paul Peña, Animal Diversity Web (ADW) /=]
Sunda slow lorises live in tropical areas mainly in primary and secondary tropical lowland forests at elevations from sea level to 1300 meters (4265 feet). forests. More particularly, they have also been found in tropical evergreen and semi-evergreen forests, seasonal wet evergreen forests, dry evergreen forests, mixed deciduous tropical forests, sub-tropical broadleaf hill forests, swamp forests, savannahs, montane and submontane forests, shrub forests, peat swamps and hardwood forests, as well as degraded habitats such as highly disturbed forests, secondary forests, disturbed primary forests and logged forests. /=\
The source of their common name,Sunda slow loris, refers to the Sunda Islands, a group of islands in the western part of the Malay archipelago where they are found. Another common name for the species is the greater slow loris. The specific name, coucang, derives from kukang, their common name in Indonesia. They are commonly known as malu-malu, meaning "shy" in Indonesian, and also as bukang or Kalamasan. In the vernacular they are sometimes called Kuskus because local people in Indonesia do not distinguish between the slow loris and Cuscus, a group of Australasian possums. In Malaysia, they are sometimes known as kongkang or kera duku; kera is Malay for monkey while duku is the fruit-bearing tree Lansium domesticum. In Thailand, they are called ling lom, which translates as "wind monkey". /=\
In the wild, Sunda slow lorises have an average life span of 20 years, including one individual that survived 22 years. Their average life span in captivity is 24 years, including the longest-lived individual on record, which survived 25.8 years. In captivity, Sunda slow lorises tend to be more stressed and aggressive, which may result in a shorter life span of 12 to 14 years.
Sunda Slow Loris Characteristics and Diet
Sunda slow lorises range in weight from 599 to 685 grams (21.1 to 24.1 ounces) and range in length from 27 to 38 centimeters (10.63 to 14.96 inches). Their average basal metabolic rate is 1.5040 cubic centimeters of oxygen per gram per hour. Their average basal metabolic rate is 1.504 watts. Sexual Dimorphism (differences between males and females) is not present: Both sexes are roughly equal in size and look similar. [Source: Paul Peña, Animal Diversity Web (ADW) /=]
Sunda slow lorises have a mostly white stripe between their eyes, beginning near the top of their forehead and descending to the end of their nose. According to Animal Diversity Web: They usually have light brown fur with a darker-colored stripe running down their back. Thick fur hides their ears. Their highly-reduced (to a stump) vestigial tail is also hidden underneath their fur. Their eyes are large due to their primarily nocturnal (active at night), activity. Their second digit is reduced; their hands act as powerful clamps for grasping. Sunda slow lorises have a toothcomb (a group of teeth with fine spaces between them) and six procumbent teeth on their lower jaw, consisting of the lower incisors and the canine teeth. Lorises use their toothcomb (a group of teeth with fine spaces between them) to scrape off gum when foraging, and rarely use their toothcomb (a group of teeth with fine spaces between them) for grooming (a common practice among other primates with toothcomb (a group of teeth with fine spaces between them)s). Like other slow lorises, these animals have wet noses, round heads, small ears hidden in thick fur, a flat face and large eyes.
Sunda slow lorises are omnivores (eats a variety of things, including plants and animals) and dietary generalists, feeding on saps, gums, wood, bark, stems, fruit, nectar or other plant fluids and occasionally arthropods such as spiders and insects as well as snails, eggs and mollusks.. Roughly one third of their diet is saps and gums, another third consists of nectar and nectar-producing plants and approximately one fourth of their diet is fruit. The remainder of their diet consists of random items, such as snails and eggs. Despite a very slow metabolic rate, this species has a high-energy diet, most likely due to the energy costs of detoxifying certain ingested plant compounds.
Sunda Slow Loris Behavior, Movement and Communication
Sunda slow lorises are arboreal (live mainly in trees), scansorial (able to or good at climbing), nocturnal (active at night), motile (move around as opposed to being stationary), sedentary (remain in the same area) and solitary. The size of their range territory is .004 to .25 square kilometers. Home ranges do not appear to be defended. When theu witness a member of their own species inside their home range, or when entering the home range of another individual, Sunda slow lorises generally exhibit no visible reaction. According to Animal Diversity Web: Although Sunda slow lorises commonly stay within their own home range, they show no hesitation in entering another individual's home range or in having others enter their own home range. The individual's range serves as a general ground for activity, with no actual attachment to the range except by habit. [Source: Paul Peña, Animal Diversity Web (ADW) /=]
Sunda slow lorises move slowly through trees on all four limbs, typically with three limbs attached to support at any given time. Their locomotion is similar to crawling. They move with little noise or change in speed. At times they may hang below a branch by one or both feet for long periods. In captivity, movement includes quadrupedal (use all four limbs for walking and running) locomotion (24 percent), climbing (21 percent), suspension (including cantilevering) (29 percent), bridging (23 percent) and other forms of locomotion (3 percent).
Sunda slow lorises are mainly solitary, spending only eight percent of their active time near other individuals. In cases of home range overlap spatial groups form, usually consisting of one male, one female and one to three younger individuals. Interactions among spatial groups are mainly positive: allogrooming, following, pant-growling and click-calling are all observed. Despite this, only three percent of active time is spent within the spatial group. This evidence may suggest a monogamous social system, though polyandrous activity has been observed.
Sunda slow lorises sense using touch, sound, ultrasound and chemicals detected by smelling. They communicate with vision, sound and chemicals usually detected by smelling and scent marks produced by special glands and placed so others can smell and taste them. Olfactory senses play a central role in species interaction, with uses ranging from alerting others of identity, to physical state and even positioning of the individual.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). During mating, females may whistle when in visual contact with a male, in order to draw attention. No alarm calls are used for signaling predators, as crypsis is the most common response for avoidance. Infants may exhibit squeaks or clicks when disturbed. Young individuals especially, but also adults, use ultrasonic vocalization when exploring new environments or during complex handling (locomotion).
Sunda Slow Loris Mating, Reproduction and Offspring
Sunda slow lorises are polyestrous, having many periods of sexual receptivity during a year. Their estrus cycle lasts 29 to 45 days, with most copulations occurring in succession. They engage in year-round breeding and typically breed once per year. The average number of offspring is one. [Source: Paul Peña, Animal Diversity Web (ADW) /=]
Slow lorises have been observed in groups of up to six members including a female in estrus and five males. This may suggest a promiscuous mating system, where females mate with more than one male. Males track females in estrus; however, females initiate the act of copulation. To initiate, the female hangs from a branch within sight of the male, often vocalizing to draw further attention. The male then holds the female and the branch, while simultaneously copulating with her. Urine-marking may also be used by the female to solicit mating. The male may create a mating plug following copulation.
The average gestation period is 188 days. The weaning age ranges from three to six months. The average weaning age is four months, with the time to independence ranging from 16 to 26 months and the average time to independence is 20 months. Only females care for their young. Before and during weaning, females lick their young, covering them in toxic oil, so the young may be protected while the female leaves to forage. Females also provide an example from which the young will learn to move through the trees. Females reach sexual or reproductive maturity at 18 to 24 months, with an average of age 20 months. Males reach sexual or reproductive maturity at 17 to 20 months, with an average of 18 months. /=\
Sunda Slow Lorises, Humans and Conservation
On the International Union for Conservation of Nature (IUCN) Red List Sunda slow lorises are listed as Vulnerable. In CITES (Convention on International Trade in Endangered Species of Wild) they are in Appendix I, which lists species that are the most endangered among CITES-listed animals and plants. Humans utilize them for pet trade and as sources of medicines as we said before. [Source: Paul Peña, Animal Diversity Web (ADW) /=]
According to Animal Diversity Web (ADW); This species is greatly threatened by the pet trade. To prevent injury for owners, their teeth are often removed, which almost always (90 percent of the time) leads to infection and painful death. Once their teeth have been removed it is also impossible to re-introduce them into the wild. Because of extreme mortality rates, mainly due to infection, improper nutrition and heightened stress, the trade is further inflated by the constant need for replacements. Likewise, human developments continue to encroach on their habitats.
The species is also threatened by gathering for illegal traditional medicine. They are also killed as a crop pest. In addition to poaching, severe habitat loss and degradation over large areas of their range have caused large population declines, despite the species being more adaptable to human habitats than most other primates in the region. The resulting fragmentation has restricted species dispersal as they depend on continuous canopy cover to move from tree to tree.
Bengal Slow Lorises
Bengal slow lorises (Nycticebus bengalensis) live in forested areas of Southeast Asia at elevations from sea level to 2400 meters (7874 feet). They are found in Cambodia, Myanmar (Burma), Thailand, Vietnam, southern regions of China and seven northeastern states of India (Assam, Arunachal Pradesh, Mizoram, Nagaland, Meghalaya, Manipur, and Tripura). They have the largest range and are the northernmost species of the slow lorises (genus Nycticebus). The greatest densities are in eastern Thailand. [Source: Reyd Smith, Animal Diversity Web (ADW) /=]
Bengal slow lorises were formerly considered one of four subspecies of Sunda slow loris (Nycticebus coucang). Their former taxonomic name being Nycticebus coucang bengalensis. Although there is some gene flow between them, the gene flow is small and molecular testing and morphological characteristics suggest there is enough variation to call each slow loris their own species. Much of the literature still describes Nycticebus bengalensis as a subspecies of Nycticebus coucang.
Bengal slow lorises are nocturnal (active at night), and arboreal (live mainly in trees), strepsirrhines. They prefer areas of high canopy cover and forest edges, where insects are more abundant. They inhabit tropical and sub-tropical rainforests as well as semi-evergreen rainforests in southeastern Asia year round. However, with increasing destruction of their habitat due to deforestation and development of land, they are forced to live in scrub forests (in areas with an extended dry season). Bengal slow lorises prefer larger and taller trees with deeper crowns that are associated with higher food abundance as well as a dense micro-habitat that provides protection from predators. They prefer older and younger plantation forests to primary forests and avoid habitats with shallow tree crowns. Their average lifespan in the wild is 15 years; in captivity it is 20 years.
Bengal slow lorises are commonly found as pets in households in southern Asia. They are sometimes used as food and in traditional "medicine." On the International Union for Conservation of Nature (IUCN) Red List they are listed as Vulnerable. In CITES (Convention on International Trade in Endangered Species of Wild) they are in Appendix I, which lists species that are the most endangered among CITES-listed animals and plants. Before 2007, Bengal slow lorises where listed Data Deficient on the IUCN Red List. However, in 2008 the IUCN Red List classified the Bengal Slow Loris as Vulnerable due to an expected 30 percent decline in the next three generations over the species’ entire range. This decline is attributed to increasing habitat destruction caused by deforestation, hunting, poaching and road kills from increased traffic.
Bengal Slow Loris Characteristics, Poison and Food
Bengal slow lorises are the largest of all of the slow lorises. They range in weight from one to two kilograms (2.2 to 4.4 pounds) and range in length from 26 to 38 centimeters (10.2 to 15 inches). Their skull length is 6.5 centimeters, also larger than any other species of loris. They are three times heavier than the pygmy loris, the smallest loris. Sexual Dimorphism (differences between males and females) is not present: Both sexes are roughly equal in size and look similar. [Source: Reyd Smith, Animal Diversity Web (ADW) /=]
According to Animal Diversity Web (ADW) Bengal slow loris fur patterns differ from other slow lorises which allow for visual differentiation from other species. They have thick, wooly fur with a white head, neck, and underside and a brown-grey dorsal side accompanied by a slight darker brown dorsal stripe running down the back. They have a round head with short ears and rostrum (hard, beak-like structures projecting out from the head or mouth) and very large, stereoscopic eyes that have an orange-red eye-shine. They have very short, almost vestigial tails.
Their hands are specifically designed for climbing and they have opposable thumbs that are significantly different from their other four phalanges, giving them a pincer-like grip. This strong grip makes up for their lack of a tail. Males and females look alike and can only be differentiated by looking at the gonads. Male Bengal slow loris testicles have an average weight of 1.2 grams, with a vas deferens length of 85.5 millimeters. The dental formula: I 2/2 C 1/1 P 3/3 meters 3/3 = 36
Bengal slow lorises primarily herbivores (primarily eat plants or plants parts). They eat a lot of eats sap as well as wood, bark, stems fruit nectar sap or other plant fluids. Animal foods include eggs, insects terrestrial non-insect arthropods. Their preferred foods are resins and gums from six species of plants which make up 94.3 percent of the diet in the winter, and 67.3 percent of their diet in the summer. Among their favored plants are Bauhinia and other liana species. Terminalia is also commonly consumed. Lorises obtain exudates using their procumbent incisors to gouge or scrape holes into the bark of trees. They then use their long, narrow tongues to scoop the exudates into their mouth. Nectar is the second preferred food with it consisting of 22.3 percent of their summer diet.
Bengal slow lorises are well camouflaged often take cover in dense vegetation to avoid predator detection. When under attack, Bengal slow lorises roll up in a defensive posture with the brachial glands on the inside of their elbows over their heads to combine the brachial gland exude with saliva. This is applied to the head for defense and is likely foul-tasting. They also bite in defense using their procumbent teeth which can deliver this saliva into the predator. Humans can have allergic reactions to this substance because it is similar in structure to Fel-d1, also known as cat allergen. This can cause anaphylactic shock in humans and other predators. Many other volatile and semi-volatile compounds are also in the loris brachial gland exudates causing ill-effects in the predators. These secretions may also serve an anti-parasitic role, as lorises have an extremely low occurrence and intensity of ectoparasite infestation compared to other primates. Known predators of Bengal slow lorises include pythons, hawk-eagles and orangutans.
Bengal Slow Loris Behavior, Communication and Reproduction
Bengal slow lorises They are arboreal (live mainly in trees), scansorial (able to or good at climbing), nocturnal (active at night), motile (move around as opposed to being stationary), sedentary (remain in the same area) and solitary. In terms of home range, The home ranges of Bengal slow lorises overlap and vary in size. Their population density ranges from 1.27 to 4.26 individuals per square kilometer. This overlap is dependent on both number of competitors and the habitat quality of the area they occupy. [Source: Reyd Smith, Animal Diversity Web (ADW) /=]
Reyd Smith wrote in Animal Diversity Web: Lorises rarely exhibit aggression towards one another and usually live in family groups. Although some individuals are solitary, most live in a social setting. There is no dominance hierarchy in social groups. They travel 20 to 30 meters each night, either alone or in pairs. They often sleep in tree holes or dense vegetation, sometimes with other lorises, and may occupy up to 60 tree holes throughout their lifetime. They are tolerant of other loris species as they have been observed foraging on the same tree within meters of pygmy slow lorises which is sympatric with Bengal slow lorises. [Source: Reyd Smith, Animal Diversity Web (ADW) /=]
Bengal slow lorises sense and communicate using vision, touch, sound and chemicals usually detected with smell. High-pitched whistles are used to attract mates in Bengal slow lorises. Females use urine scent-marks to attract mates when in estrus. Chitters and clicks are used by infants to get their mother’s attention as well as to call her back when they are parked and the mother is out looking for food. Large stereoscopic eyes assist increase their vision at night.
Bengal slow lorises are polygynandrous (promiscuous), with both males and females having multiple partners. They engage in year-round breeding. They probably breed every two years and probably breed throughout the year. The number of offspring is usually one. The gestation period ranges from 176 to 198 days. The weaning age ranges from six (low) months, with the time to independence ranging from six to 18 months. Females and males reach sexual or reproductive maturity at one to 1.5 years.
Reyd Smith wrote in Animal Diversity Web: Once slow loris females are in estrus, they use a combination of urine marking and whistle calls to attract males in the area. The female will verify the male’s reaction to her calls by intermittently stopping and turning her head. The male will respond by sniffing her urine mark then urine marking on top. The male will then whistle back to her and approach her. She will assume a copulatory-invitation posture as she drops below a branch. After copulation, social grooming or social play may follow. A female may mate with multiple males throughout her 37 to 54 day estrus. Males also mate with multiple females. [Source:Reyd Smith, Animal Diversity Web (ADW) /=]
Pygmy Slow Lorises
Pygmy slow lorises (Nycticebus pygmaeus) are found in tropical areas in forests and rainforests at elevations up to 1500 meters (4920 (high) feet) in Vietnam, Laos, eastern Cambodia, and neighboring regions of southern China (southeast Yunnan province). It not known whether those in China are native or introduced. In Vietnamese folklore, pygmy slow lorises are called "khi gio", or "monkeys that move with the wind." They believe the animals portend bad fortune and are used for black magic. [Source: Margaret Gray, Animal Diversity Web (ADW) /=]
Pygmy slow lorises do well in degraded habitats, rainforests and bamboo thickets in Vietnam and evergreen forest in Laos. 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 three to 12 meters in the canopy.
Pygmy slow lorises are primarily insectivores (mainly eat insects) but can also be described as herbivores (eat plants or plants parts), frugivores (eat fruits) omnivores (eats a variety of things, including plants and animals). Animal foods include eggs, insects. Among the plant foods they eat are fruit nectar flowers sap or other plant fluids. They also eat fungus. 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.
See Separate Article: PYGMY SLOW LORISES factsanddetails.com
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Text Sources: Animal Diversity Web animaldiversity.org ; National Geographic, Live Science, Natural History magazine, David Attenborough books, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Discover magazine, The New Yorker, Time, Reuters, Associated Press, AFP, Lonely Planet Guides, Wikipedia, The Guardian, Top Secret Animal Attack Files website and various books and other publications.
Last updated December 2024