JAVAN SLOW LORIS
Nycticebus javanicus
Geographic Distribution and Habitat
Javan slow lorises are endemic only to the western and central parts of the island of Java, Indonesia. They are found in both the primary and secondary forests—including mangroves, bamboo forests, and chocolate plantations.
Being arboreal creatures—like most prosimians, or primitive primates, tend to be—Javan slow lorises thrive in regions where they can swing slowly through vines and lianas, instead of from tree to tree.
Prior to the 2000s, they were thought to be a sub-species of the Sunda slow loris, until a re-assessment of their morphology and genetics led to the species' elevation to the status of a distinct species.
The loris is the only existing venomous primate species in the world. Their venom is produced by mixing secretions from a gland on their elbow with their own saliva, which is then penetrated into the bloodstream of their victims using their razor-sharp teeth. The primary function of producing venom is to protect themselves from parasites and other predators. Their venom can cause a serious allergic reaction in humans, resulting in swelling or even anaphylactic shock, and can be deadly for smaller mammals.
Javan slow lorises are endemic only to the western and central parts of the island of Java, Indonesia. They are found in both the primary and secondary forests—including mangroves, bamboo forests, and chocolate plantations.
Being arboreal creatures—like most prosimians, or primitive primates, tend to be—Javan slow lorises thrive in regions where they can swing slowly through vines and lianas, instead of from tree to tree.
Prior to the 2000s, they were thought to be a sub-species of the Sunda slow loris, until a re-assessment of their morphology and genetics led to the species' elevation to the status of a distinct species.
The loris is the only existing venomous primate species in the world. Their venom is produced by mixing secretions from a gland on their elbow with their own saliva, which is then penetrated into the bloodstream of their victims using their razor-sharp teeth. The primary function of producing venom is to protect themselves from parasites and other predators. Their venom can cause a serious allergic reaction in humans, resulting in swelling or even anaphylactic shock, and can be deadly for smaller mammals.
Javan slow loris geographic range. Map credit: Chermundy and IUCN
Size, Weight, and Lifespan
Both males and females are approximately 11.5 in (29.2 cm) in head-body length, and between 1 to 1.5 lbs (.45 to .68 kg) in weight. Javan slow lorises are known to live as long as 25 years in captivity. Appearance
These small, fuzzy creatures have a large, wide-eyed stare, with forward-facing eyes. A prominent white diamond-shaped pattern runs between their eyes and extends over their foreheads. Their tiny torsos are generally brownish-grey in color with a creamy hue over the head, neck, and shoulders. A distinct cream-colored stripe runs over the dorsal surface of their bodies. |
What Does It Mean?Arboreal:
Physically adapted to living primarily or exclusively in trees, such as arboreal-dwelling (tree-dwelling) monkeys. Estrus: A recurring period of sexual receptivity and fertility in female mammals. Liana: A woody climbing plant that hangs from trees, especially in tropical rainforests. Nocturnal: Active at night. Prosimian: The most primitive of the primates. "Prosimian" means pre-monkey. The living (extant) prosimians are in the suborder Prosimii, which includes four families of lemurs, the bush babies (galagos), lorises and pottos, and the tarsiers. |
Photo credit: Dr K A I Nekaris/Creative Commons
Diet
The Javan slow loris is an omnivore with quite a varied pallet, consisting of flowers, sap, nectar, fruit, insects, eggs, birds, and small vertebrates like lizards or even small mammals. Despite such a variety of options to choose from, they tend to spend approximately 90% of their feeding time eating nectars.
Their slow lifestyle results from their extremely low metabolic rate, compared to other similar-sized mammals. For these nocturnal creatures, around 20% of their nightly activities involve feeding.
The Javan slow loris is an omnivore with quite a varied pallet, consisting of flowers, sap, nectar, fruit, insects, eggs, birds, and small vertebrates like lizards or even small mammals. Despite such a variety of options to choose from, they tend to spend approximately 90% of their feeding time eating nectars.
Their slow lifestyle results from their extremely low metabolic rate, compared to other similar-sized mammals. For these nocturnal creatures, around 20% of their nightly activities involve feeding.
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Behavior and Lifestyle
Movement for this species is described as a very slow and deliberate hand-over hand form of quadrupedalism, where they walk on all four limbs. This form of movement is strikingly similar to crawling. Their exceptionally strong fingers and toes allow them to maintain a powerful grip on branches for extended periods of time. While quadrupedal locomotion is the predominant method by which slow lorises get around, other forms of movement that they are likely to use include climbing, suspension, and bridging. |
Fun FactThe loris is one of only seven mammals in the world that are venomous. |
Daily Life and Group Dynamics
Although little is known about the social structure of the Javan slow loris, they tend to spend their nights foraging for food alone. They also tend to sleep alone throughout the day, barring the occasional group nap with others.
Although little is known about the social structure of the Javan slow loris, they tend to spend their nights foraging for food alone. They also tend to sleep alone throughout the day, barring the occasional group nap with others.
Communication
The predominant forms of communication in this species include acts of social grooming and olfaction, using scent marking.
Because their lower incisors and canines lie down and face outwards, a toothcomb dental structure is formed to aid in the facilitation of social grooming, which is an integral part of their social activities. Scent marking with urine is the most common way for them to mark their territorial boundaries.
Adult males are, more often than not, aggressive and territorial in nature toward other males, and will make a low buzzing growl or hiss to express annoyance or anger. Females in estrus will produce a high-pitched whistle to attract male attention.
The predominant forms of communication in this species include acts of social grooming and olfaction, using scent marking.
Because their lower incisors and canines lie down and face outwards, a toothcomb dental structure is formed to aid in the facilitation of social grooming, which is an integral part of their social activities. Scent marking with urine is the most common way for them to mark their territorial boundaries.
Adult males are, more often than not, aggressive and territorial in nature toward other males, and will make a low buzzing growl or hiss to express annoyance or anger. Females in estrus will produce a high-pitched whistle to attract male attention.
Reproduction and Family
Javan slow lorises are polygamous primates who reproduce year-round. Males reach sexual maturation and are able to reproduce as early as 10 months of age, whereas females reach that stage at the 17- to 20-month mark.
The gestation period lasts for approximately 6 months and results in the birth of 1 to 2 offspring, who are entirely developed by the time they are born.
Both sexes take turns carrying the new infant around while the other forages the forest for food. The mother will sometimes clean her baby with venom saliva before going out, which helps protect the offspring from nearby predators.
Javan slow lorises are polygamous primates who reproduce year-round. Males reach sexual maturation and are able to reproduce as early as 10 months of age, whereas females reach that stage at the 17- to 20-month mark.
The gestation period lasts for approximately 6 months and results in the birth of 1 to 2 offspring, who are entirely developed by the time they are born.
Both sexes take turns carrying the new infant around while the other forages the forest for food. The mother will sometimes clean her baby with venom saliva before going out, which helps protect the offspring from nearby predators.
Ecological Role
Like most primates whose diets consist of flowers and plants, Javan slow lorises are thought to be seed dispersers, which helps to regenerate their forest habitats.
Since lorises are exclusively nocturnal, they have been largely successful in avoiding direct competition when it comes to hunting for food resources. Foraging after the sun sets also allows them to easily hide from predators as they feed on nighttime insects, thus controlling the pest population.
Like most primates whose diets consist of flowers and plants, Javan slow lorises are thought to be seed dispersers, which helps to regenerate their forest habitats.
Since lorises are exclusively nocturnal, they have been largely successful in avoiding direct competition when it comes to hunting for food resources. Foraging after the sun sets also allows them to easily hide from predators as they feed on nighttime insects, thus controlling the pest population.
Conservation Status and Threats
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The Javan slow loris is classified as Critically Endangered on the International Union for the Conservation of Nature Red List of Threatened Species (IUCN, 2015), which cites a decline of at least 50% of their population over the last three generations due to increased persecution and pet trade activities.
Javan slow lorises are one of the most endangered primate species. They are listed as one of "The World's 25 Most Endangered Primates", 2016-2018 and again in the 2018-2020 report, by the International Union for Conservation of Nature Species Survival Commission Primate Specialist Group (IUCN/SSC PSG), the International Primatological Society (IPS), and Conservation International (CI). Popular YouTube videos of these creatures portray them as cute house pets, and have helped fuel the massive illegal pet trade industry that plagues their survival. Since the loris' bite is toxic and can be harmful to humans, traffickers pull out their teeth without the use of any antibiotics when captured. As a result, many of them die while in transit. |
Human-induced habitat loss throughout Southeast Asia is another major threat to the Javan slow loris. As more forests are cleared out for housing development or for palm oil plantations, they are more exposed to poachers and other predators.
In addition to this, lorises are heavily hunted for uses in traditional Asian medicine. Although not scientifically proven, it is believed in some Asian countries that consuming their flesh can treat leprosy, heal wounds and broken bones, and even help women heal after giving birth.
Natural predators of the slow loris include eagles, hawks, orangutans, and snakes. When confronted by any of these creatures, the slow loris tends to either fall away from the threat by unclasping its support grip, biting, or even rolling up in a manner that exposes their venomous elbow oils on the surface of its back.
In addition to this, lorises are heavily hunted for uses in traditional Asian medicine. Although not scientifically proven, it is believed in some Asian countries that consuming their flesh can treat leprosy, heal wounds and broken bones, and even help women heal after giving birth.
Natural predators of the slow loris include eagles, hawks, orangutans, and snakes. When confronted by any of these creatures, the slow loris tends to either fall away from the threat by unclasping its support grip, biting, or even rolling up in a manner that exposes their venomous elbow oils on the surface of its back.
Conservation Efforts
The Javan slow loris and Appendix I of Convention of International Trade in Endangered Species (CITES), which regulates wildlife trade, and is protected under Indonesian law and international commercial trading of the species is considered illegal.
The International Animal Rescue of Indonesia attempts to improve the rehabilitation process for confiscated Javan slow lorises, so that they can be reintroduced to the wild with minimal issues in re-adjusting.
The Little Fireface Project, named after the Sudanese word for loris, works to conserve these primates through research, educational workshops, and campaigns that bring awareness to the pet trade issues.
Other organizations involved in the conservation of the Javan slow loris include the LDVI International, Wildlife Friends Foundation of Thailand, and Monkeyland Primate Sanctuary.
The Javan slow loris and Appendix I of Convention of International Trade in Endangered Species (CITES), which regulates wildlife trade, and is protected under Indonesian law and international commercial trading of the species is considered illegal.
The International Animal Rescue of Indonesia attempts to improve the rehabilitation process for confiscated Javan slow lorises, so that they can be reintroduced to the wild with minimal issues in re-adjusting.
The Little Fireface Project, named after the Sudanese word for loris, works to conserve these primates through research, educational workshops, and campaigns that bring awareness to the pet trade issues.
Other organizations involved in the conservation of the Javan slow loris include the LDVI International, Wildlife Friends Foundation of Thailand, and Monkeyland Primate Sanctuary.
References:
- http://pin.primate.wisc.edu/factsheets/entry/slow_loris
- http://blog.nus.edu.sg/lsm4262species/2013/04/16/the-lethal-primate-the-javan-slow-loris/
- https://www.arkive.org/javan-slow-loris/nycticebus-javanicus/
- http://www.iucnredlist.org/details/39761/0
- https://news.mongabay.com/2017/11/in-search-of-the-fireface-the-precarious-scandalous-lives-of-the-slow-lorises-of-java/
- https://www.alltheworldsprimates.org/Members/Home/MasterPrimate.aspx?tid=940
- https://www.edgeofexistence.org/species/javan-slow-loris/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3852360/
- https://www2.palomar.edu/anthro/primate/prim_3.htm
- http://www.bbc.co.uk/nature/adaptations/Vivipary
Written by Nina Shangari, February 2018
