Found exclusively in South and Southeast Asia, slow lorises are the world’s only venomous primates. They’re arboreal—meaning they live in trees—and can be spotted curling up to sleep in branches or using vines and leaves to get around. They typically only come down to the forest floor when they need to defecate.
There are nine species of slow loris. They all belong to the same genus, with each species sharing many similar characteristics and behaviours. The nine species include the Philippine slow loris, Bengal slow loris, greater slow loris, Kayan slow loris, Bangka slow loris, Bornean slow loris, Sumatran slow loris, Javan slow loris, and pygmy slow loris.
These small, nocturnal creatures are characterised by their large, round eyes, which are adapted for night vision. They have compact bodies, short snouts, dense fur, and distinctive facial markings. On average, they measure 20 to 37 centimetres (or 10 to 15 inches) long.
Slow lorises each have a small bare patch under their arm that secretes oil. When they feel threatened, they lick this oil, which combines with their saliva to create a venom strong enough to kill small arthropods and mammals.
Slow lorises are skilled hunters; they use their slow and deliberate movements to catch prey like insects and small vertebrates. They also have a specialised toothcomb—a unique structure created by their bottom front teeth—that they use for grooming and extracting gum from trees.
Slow lorises are generally solitary and territorial animals. They have the ability to stay motionless for long periods, which is how they got their name—observers noted how slow they were compared to other forest-dwelling animals.
True to their name, slow lorises have a relatively slow reproductive rate, with females typically giving birth to one offspring per year after five to six months of gestation. The infant clings to its mother and is nursed for several months before becoming more independent.
Slow lorises contribute to the health and biodiversity of their ecosystems through seed dispersal and insect control. They also serve as indicators of environmental well-being. They are prey for snakes, eagles, and the occasional orangutans, while also preying on smaller animals and keeping the food chain in check. As omnivores, they consume nectar, which is a very important process for ecosystem regeneration, as they inadvertently transfer pollen between flowers. Similarly, as they eat and digest fruit, they spread seeds through their faeces and contribute to the propagation of the forest’s plants.
Without slow lorises, the ecosystems in which they live would not be able to thrive. Protecting these primates is not only crucial for their own survival but also for the overall balance of their habitats.
Read on to learn more about slow lorises and how we can protect them.
What is a slow loris’ scientific name?
Slow lorises belong to the genus Nycticebus. Each species of slow loris has its own specific name.
- Philippine slow lorises, Nycticebus menagensis
- Bengal slow lorises, Nycticebus bengalensis
- Greater slow lorises, Nycticebus coucang
- Kayan slow lorises, Nycticebus kayan
- Bangka slow lorises, Nycticebus bancanus
- Bornean slow lorises, Nycticebus borneanus
- Sumatran slow lorises, Nycticebus hilleri
- Javan slow lorises, Nycticebus javanicus
- Pygmy slow lorises, Nycticebus pygmaeus
Are slow lorises endangered?
- Vulnerable slow loris species include the Philippine slow loris, Kayan slow loris, and Bornean slow loris.
- Endangered species include the Bengal slow loris, greater slow loris, Sumatran slow loris, and pygmy slow loris.
- The two species considered critically endangered are the Bangka slow loris and Javan slow loris.
Where do slow lorises live?
Slow lorises are found in South and Southeast Asia, often in swampy areas or humid tropical rainforests, though are also known to live in dry forested habitats. Slow lorises live in the trees to escape ground predators and have adaptations to help them thrive among branches and foliage.
Each species is found in a different area of the continent. The smallest species, the pygmy slow loris, is restricted to forests east of the Mekong River, while the larger Sunda slow loris inhabits peninsular Malaysia and the Indonesian island of Sumatra.
The Philippine slow loris inhabits the island of Borneo and the southern Philippine islands.
The Bengal slow loris is native to parts of Bangladesh, China, and Southeast Asia.
The Kayan slow loris is also found on Borneo, as is the Bornean slow loris.
The Bangka slow loris is only found on the small island of Bangka, Indonesia.
The Sumatran slow loris lives only on Sumatra, and the Javan slow loris lives only on the island of Java, Indonesia.
Every species of slow loris has a decreasing population because of the number of threats these small creatures face.
Exotic pet trade and tourist attractions
The slow loris are predominantly affected by the exotic pet trade, as their round eyes and furry coats make them look like cute, cuddly creatures. Traders cut or extract their teeth to make them seem like safe pets for children, but this often results in blood loss, infection, and even death. Most captive slow lorises that are kept as pets receive improper care and die from poor nutrition, stress, or infection. This has only increased demand for them from illegal traders, who now hunt slow lorises on a commercial scale, rather than just opportunistically.
Slow lorises are also hunted for bushmeat and for ingredients in traditional medicine.
Just like many other species around the world, slow lorises face extensive habitat loss as a result of human expansion and urbanisation—particularly from palm oil plantations. The major threats that their habitat faces include farming, deforestation, human settlement, road building, dams, power lines, fragmentations, soil loss and erosion, and deliberately set fires.
Slow lorises rely on vines and hanging branches to move safely around their habitat. When these are cleared or destroyed, it impacts their ability to feed and defend themselves. High numbers of slow lorises have been found dead on power lines or become victims of roadkill in areas where roads cut between forest patches.
Wildfires—both naturally occurring and human-caused—are leading to extensive habitat loss for slow lorises. In Borneo, for example, in 2015, forest fires tore across the island, burning acres of forest and leading to a significant decrease in the habitat of slow lorises, among other animals.
While climate change is a cause behind some fires, many are also caused by farmers logging and clearing land for agricultural purposes.
Are slow lorises poisonous?
Slow lorises are venomous. Though it may look like a cute ball of fluff, a slow loris has a deadly venom that is strong enough to send a human into anaphylactic shock. When it feels threatened, it raises its arms and licks its brachial gland, a raised bald patch on its inner arm.
It secretes a noxious oil which, when mixed with the slow loris’ saliva, creates a venomous solution. This activated venom is transferred when it bites another animal, at which point the venom enters the victim’s bloodstream.
The venom causes pain, swelling, and a festering wound. It’s strong enough to kill small mammals and arthropods, and can cause anaphylactic shock and heart irregularities in humans. There is one known case of a slow loris causing death in a human.
Are slow lorises nocturnal?
Yes, these primates are nocturnal. They sleep curled up in a tree by day and forage for food at night.
How big is a slow loris?
The size of a slow loris varies by species. The smallest species, the pygmy slow loris, measures about 25 centimetres (10 inches) long. The larger Sunda slow loris is about 27 to 37 centimetres (11 to 15 inches) long.
How long do slow lorises live?
Is a slow loris a monkey?
A slow loris is not a monkey, but it is a primate. They belong to a primate group called the Strepsirrhini, which also includes the lemurs of Madagascar, the bushbabies and pottos of Africa, and the slender lorises of India and Sri Lanka.
What does a slow loris eat?
Slow lorises are omnivores—they eat everything from small birds and reptiles to fruit, nectar, and insects. They often hang upside down from tree branches so they’re able to eat with both hands.
Their bottom front teeth create a structure called a toothcomb, which is used both for grooming and for gouging holes in tree trunks, from which they extract gum with their long, narrow tongues. In a single night, an individual slow loris can bore over 100 holes in trees.
What does a slow loris look like?
The nine species of slow loris look quite similar. They each have a stocky body, short, stout limbs, rounded snouts, and round eyes.
Slow lorises have distinct facial markings which, to the human eye, make them look cute. However, these dark, teardrop-shaped markings around their eyes are a warning sign to potential predators and draw attention to their venomous mouths. Slow lorises also have contrasting fur tones to signal aggressiveness—a defence technique called ‘aposematic colouration’.
A slow loris also has a dark stripe of fur on its back, which can appear snake-like from a distance. One theory goes that lorises evolved these features over time as a form of mimicry to confuse predators into thinking they were snakes.
Are slow lorises good pets?
No. Slow lorises are wild, endangered animals that belong in their natural habitats. They are the world’s only venomous primates and have the potential to cause serious harm to you or other pets in your home.
Removing slow lorises from the natural forests in which they live also causes negative effects in their ecosystems.
Is the slow loris endangered?
Slow lorises have a declining population. The nine species of slow loris fit into three different categories, according to the IUCN:
- Vulnerable: Philippine, Kayan, and Bornean slow lorises
- Endangered: Bengal, greater (also known as Sunda), Sumatran, and pygmy slow lorises
- Critically endangered: Bangka and Javan slow lorises
Though different slow loris populations face different threats, all of them are in constant danger from the illegal pet trade. Their size and appearance makes them a popular exotic pet, despite the dangers they pose to people.
Other threats include habitat loss and forest fires, which you can read more about above.
IFAW is dedicated to helping protect endangered animals around the world, including slow lorises.
We have been a part of multiple projects across South and Southeast Asia to help slow loris populations. In 2022, a slow loris with grave injuries was admitted to our partners at the Wildlife Trust of India (WTI) Centre for Wildlife Rehabilitation and Conservation. Left on its own, it certainly would have perished in the wild. Thankfully, the animal received timely intervention and surgery from WTI’s expert team. After the surgery, the team carefully monitored the slow loris during its rehabilitation. When the primate’s mobility improved, and it could easily forage for hidden fruits, insects, and eggs in the rehabilitation enclosure, it was released back into the wild.
We’re deeply committed to helping all animals that are victims of the illegal wildlife trade. Our partners WTI and Jakarta Animal Aid Network (JAAN) carried out an undercover investigation that aimed to disrupt and dismantle online trafficker networks. In 2022, we supported JAAN in rescuing several wild animals from traffickers in Indonesia, including a Javan slow loris, a baby orangutan, two Sunda leopard cats, and a pregnant pangolin.
TRIPOD (Targeting Regional Investigations for Policing Opportunities & Development) is another wildlife trafficking prevention project supported by IFAW. For this project, IFAW provides sustainable solutions for live wild animals seized or confiscated from illegal trade, sending them to be properly cared for in proper facilities.
How can you help?
IFAW can continue supporting these life-saving rescue operations for slow lorises and other animals—and continue to combat wildlife trafficking at its roots—thanks to people like you.