Meet the slow loris: small, slow, and astonishingly strange
Slow lorises are small, big-eyed primates that move through the night-time canopies of South and Southeast Asia with a deliberate, hand-over-hand crawl. Cute as they look in viral clips, the reality of their biology — and their plight — is far more remarkable, and far more troubling. Here are twelve things worth knowing, every one of them grounded in the science.
1. They are the only venomous primates on Earth
No other primate produces venom. A slow loris draws a secretion from a gland near its elbow, mixes it with saliva, and can deliver a bite toxic enough to cause severe reactions in people.
2. The venom comes from the elbow
The brachial gland on the inside of each arm produces an oily secretion. When a loris licks it, the two-part venom is armed and ready in the mouth.
3. Raised arms mean fear, not joy
The famous "arms up" pose shared as a tickle reaction is actually a defensive posture — the animal is reaching for its venom gland because it feels threatened.
4. There are around nine species
Eight sit in the genus Nycticebus, and in 2022 the pygmy slow loris was moved into its own genus, Xanthonycticebus pygmaeus.
5. They are not monkeys
Slow lorises are strepsirrhine primates — closer kin to lemurs and bushbabies than to monkeys.
6. Their eyes glow in torchlight
A reflective layer behind the retina, the tapetum lucidum, amplifies dim light and shines back at a flashlight — which is exactly how poachers freeze them at night.
7. They are gum specialists
Tree gum and sap form a major part of the diet, supplemented with nectar, fruit, insects and the occasional small vertebrate. This makes them exudativores and notoriously hard to feed in captivity.
8. They move in slow motion for a reason
Their unhurried, non-leaping climb helps them stay invisible to predators in the dark.
9. Mothers "paint" their babies with venom
Females coat their infants in the gland secretion, an apparent deterrent to predators while the young are parked on branches.
10. They can live around two decades in care
Lifespans of up to roughly 20 years have been recorded in human care, with the pygmy slow loris averaging around 17.
11. Every species is threatened
According to the IUCN Red List, all assessed slow lorises are declining — ranging from Vulnerable to Critically Endangered.
12. International trade has been banned since 2007
All slow lorises sit on CITES Appendix I, so commercial international trade is illegal. Read the full slow loris species guide for the complete conservation picture.
WARN's partners in Indonesia and Malaysia care for confiscated lorises through months of dental treatment and dietary recovery. If these animals move you, a quiet way to help is the slow loris appeal.
Read the full Slow loris wildlife guide for the facts, IUCN status and conservation context — or donate to WARN to help fund the local partners protecting this species.
