Monkey Species · Southeast Asia
Long-tailed Macaque
The long-tailed or crab-eating macaque (Macaca fascicularis) is a highly adaptable Southeast Asian monkey, at home from mangroves to cities.
By the WARN Research & Conservation TeamChecked against IUCN Red List & CITES sourcesLast updated
In brief
The long-tailed or crab-eating macaque (Macaca fascicularis) is a highly adaptable Southeast Asian monkey, at home from mangroves to cities. Once considered abundant, it was uplisted to Endangered by the IUCN in 2022 after heavy trapping for the laboratory trade and persecution.
Long-tailed Macaque: At a Glance
| Origin | Southeast Asia |
|---|---|
| Size | Medium (3–9 kg) |
| Typical weight | 3–9 kg; tail as long as the body |
| Lifespan | 15–30 years (wild) |
| Coat & markings | Grey-brown coat with a long tail and a small crest; pale cheeks |
| Temperament | Adaptable, intelligent, water-loving |
| Conservation note | Endangered (IUCN, 2022); CITES Appendix II — heavily trapped for the research trade and persecuted as a pest across its range |
History & Origins
The long-tailed macaque ranges across Southeast Asia — a WARN partner region — swimming readily and foraging on crabs, fruit and human food. Long seen as a pest and exported in huge numbers for biomedical research, it was reassessed as Endangered in 2022 as trapping, persecution and habitat loss outpaced its adaptability. It also threatens island endemics where introduced.
Long-tailed Macaque Fun Facts
- It is also called the crab-eating macaque for its shoreline foraging.
- It swims well and will dive for food.
- Despite being adaptable, it was uplisted to Endangered in 2022.
- Some populations use stone tools to crack shellfish.
Long-tailed Macaque Common Health Issues
Conditions seen more often in this breed, and how owners and vets help manage them. This is general guidance, not veterinary advice — always speak to your vet.
Trapping for research and trade
Large-scale trapping for the laboratory and pet trades has driven steep declines in some heavily exploited macaques.
Care: Support enforcement of trade limits and humane, reduced reliance on wild-caught primates.
Human-wildlife conflict
Crop raiding and scavenging near settlements lead to retaliatory killing, trapping, electrocution and vehicle strikes.
Care: Support coexistence programmes, secure waste and crops, and never feed wild troops — feeding worsens conflict.
Habitat loss (wild)
Deforestation for agriculture, logging and development removes the food trees and connected canopy that wild monkeys depend on.
Care: Support habitat protection and deforestation-free supply chains in range countries rather than wildlife tourism that disturbs troops.
Monkeys belong in the wild
Monkeys are intelligent, social primates — not pets. The illegal pet trade and habitat loss threaten species from marmosets to macaques. WARN funds anti-trafficking and habitat work for primates in our partner countries.
