Mammals
Slow Loris
Nycticebus · also called slow loris, Sunda slow loris
The slow loris looks like a soft-toy version of a primate — round-faced, huge-eyed, unhurried — but it is the only venomous member of the primate order. It licks a gland inside its elbow, turns the secretion toxic with its saliva, and bites wounds that swell, fester, and occasionally kill.
Overview
Slow lorises — eight species in the genus Nycticebus — live in rainforest and forest edge across South and Southeast Asia. They are strictly nocturnal and eat a lot of tree gum and sap, gouged from bark, plus nectar, fruit, and insects. They range from about 20 to 40 cm and have a hidden stub tail and an extremely strong grip.
The only venomous primate
A gland on the inner upper arm secretes an oil that becomes toxic when mixed with saliva. The loris licks the gland, then bites, channelling venom through the needle-like teeth of its lower toothcomb. It also grooms the venom into its fur and onto parked infants. The venom is used mostly in savage territorial fights between lorises, and to deter predators and parasites. In humans, bites cause severe swelling and slow-healing wounds, and have triggered anaphylactic shock and at least one death.
Slow by design
The loris creeps hand-over-hand in silence, freezing when disturbed. A special blood network in its limbs lets it hold a motionless grip for hours.
Status
The slow loris is Endangered and declining. Every species is threatened by habitat loss and by being one of the most trafficked primates on Earth — for pets, medicine, and tourist photo props. Traders clip out the front teeth so the animals cannot bite; most then die of infection or stress. Viral “tickling” videos show lorises raising their arms in a defensive venom posture, not enjoyment.
Slow Loris: common questions
Is the slow loris really venomous?
Yes — it is the only primate known to be venomous, and one of only a handful of venomous mammals. The mechanism is unusual. A slow loris has a gland on the inside of each upper arm that oozes a clear, strong-smelling oil. When threatened, the loris raises its arms over its head and licks these glands; the secretion mixes with its saliva and undergoes a chemical change that makes it toxic. The loris can then bite, channelling the venom along grooves between its needle-sharp lower incisors and canines (a structure called the toothcomb) into the wound. It also licks the venom through its fur, so a bite from any part of the body can be affected.
How bad is a slow loris bite to a human?
Worse than the animal's size suggests. Bites cause immediate sharp pain, then significant swelling, oozing, and slow, poor healing of the wound, sometimes with tissue death around the bite that can take months to resolve. The most serious risk is anaphylaxis — several people bitten by pet or wild-caught slow lorises have gone into anaphylactic shock, and at least one death has been attributed to it. The venom appears to work partly by mimicking a protein in cat dander, which is a common human allergen, so people already sensitive to cats may react most severely. This is a major reason keeping slow lorises as pets is dangerous as well as cruel.
Why is the slow loris so threatened?
Two pressures act together. Its Southeast Asian forest habitat is being cleared rapidly for agriculture, plantations, and development. On top of that, slow lorises are among the most heavily trafficked primates on Earth, taken from the wild in huge numbers for three markets — the exotic pet trade, traditional medicine (their body parts are wrongly believed to treat many ailments), and the tourist photo-prop trade in places like Thailand. Because their reproduction is slow — usually a single infant every 12 to 18 months — populations cannot absorb these losses. Viral videos of pet lorises being "tickled" (they are actually raising their arms in a defensive venom posture) have repeatedly driven spikes in demand.
Do slow lorises make good pets?
No, on every count. They are wild, Endangered animals, and international commercial trade in all species is banned under CITES Appendix I, so nearly every pet loris is illegally sourced. Traffickers routinely clip or pull out the animal's front teeth without anaesthetic so it cannot deliver a venomous bite, which causes chronic pain and infection and means the animal can never be returned to the wild. Lorises are nocturnal and highly stressed by daytime handling and bright light, need a specialised diet of gum and insects that owners almost never provide, and can inflict a medically serious bite. Rescue centres across Southeast Asia are full of confiscated lorises that cannot be released.