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Long-tailed macaque
Macaca fascicularis

Conservation status:
Least concern

Life span: 31 years
Total population: Unknown
Regions: Philippines, Malaysia, Indonesia, Burma, India, Vietnam, Cambodia, Laos, Thailand
Gestation: 5.5 months (165 days)
Height: 412 to 648 mm (M), 385 to 503 mm (F)
Weight: 4.7 to 8.3 kg (M), 2.5 to 5.7 kg (F)

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Suborder: Haplorrhini
Infraorder: Simiiformes
Superfamily: Cercopithecoidea
Family: Cercopithecidae
Subfamily: Cercopithecinae
Genus: Macaca
Species: M. fascicularis
Subspecies: M. f. atriceps, M. f. aurea, M. f. condorensis, M. f. fascicularis, M. f. fusca, M. f. karimondjawae, M. f. lasiae, M. f. philippinensis, M. f. tua, M. f. umbrosa

Other names: M. cynomolgus or M. irus; crab-eating macaque, cynomolgus monkey, kera macaque, or longtail macaque; macaque crabier or macaque de buffon (French); macaca cangrejera (Spanish); javaapa or krabbmakak (Swedish); M. f. atriceps: dark-crowned long-tailed macaque; M. f. aurea: Burmese long-tailed macaque; M. f. condorensis: Con Song long-tailed macaque; M. f. fusca : Simeulue long-tailed macaque; M. f. karimondjawae: Kemujan long-tailed macaque; M. f. lasiae: Lasia long-tailed macaque; M. f. philippinensis: Philippine long-tailed macaque; M. f. tua: Maratua long-tailed macaque; M. f. umbrosa: Nicobar long-tailed macaque


The subspecies of long-tailed macaques vary in color from light brown or grayish to brown fur covering their backs, legs, and arms while their undersides are much lighter (Rowe 1996; Groves 2001). They have pinkish-brown faces and the fur on their heads sweeps back over their forehead, often creating a crest of hair on the top of their heads. Males have mustaches and cheek whiskers that frame their faces while females have beards as well as cheek whiskers. Both males and females have white coloration on the eyelids near the nose (Rowe 1996). The defining characteristic, for which they are named, is their extraordinarily long tail that is almost always longer than their height from head to rump, and ranges in length between 400 and 655 mm (1.31 and 2.15 ft) (Fa 1989; Groves 2001). Infants have a natal coat and are born black, changing to the adult pelage as they mature (Rowe 1996). By two to three months of age, they begin to lose their black coat and by one year, they have the adult coloration (Fooden 1995). Like other macaques (Macaca), long-tailed macaques are sexually dimorphic (Dittus 2004). Males measure between 412 and 648 mm (1.35 and 2.13 ft) and weigh, on average, between 4.7 and 8.3 kg (10.4 and 18.3 lb). Females measure only 385 to 503 mm (1.26 to 1.74 ft) and have average weights between 2.5 and 5.7 kg (5.5 and 12.6 lb) (Fa 1989). In addition to being taller and heavier, males have much larger canine teeth than females (Dittus 2004). Macaques have cheek pouches in which they can store food as they forage, and transport it away from the foraging site to eat (Lucas & Corlett 1998).

These macaques are primarily arboreal and can leap distances between trees up to five meters (16.4 ft), using their long tails for balance (Rodman 1991; Rowe 1996). Long-tailed macaques move quadrupedally through the canopy and spend some amount of time on the ground (Rodman 1991).


Macaca fascicularis

Long-tailed macaques are widespread throughout the islands of Southeast Asia into mainland Asia. They are found in the Philippines, in mainland Malaysia and on Borneo, in Indonesia on Sumatra, Java, Timor, and the Lesser Sunda Islands, in Burma, in India on the Nicobar Islands, and in Vietnam, Cambodia, Laos and Thailand (Fittinghoff & Lindburg 1980; Groves 2001). Longtail macaques are also found on Angaur Island, Palau where they were introduced in the 1900s. During the period of German rule, miners are said to have brought a pair of long-tailed macaques to the island the entire population is thought to have arisen from these two animals (Poirier & Smith 1974). They were also introduced to Tinjil Island, Indonesia in 1988 as part of the establishment of a natural habitat breeding facility to supply biomedical research (Fittinghoff & Lindburg 1980; Kyes 1993). These breeding colonies were established after a 1981 meeting of the World Health Organization which resulted in the promotion of natural breeding colonies in habitat countries that would serve as supply populations for essential biomedical research while conserving other populations of the same species (Kyes et al. 1998). Prior to the introductions in Palau and Indonesia, long-tailed macaques were introduced by Portuguese explorers to the island of Mauritius in the Indian Ocean. This introduction is thought to have occurred at least as early as the 17th century, but could have been as early as the 16th century. This population has since grown to about 35,000 animals and these long-tailed macaques are culled and exported for use in biomedical research (Sussman & Tattersall 1986; Bonnotte 2001).


Long-tailed macaques live in primary, secondary, coastal, mangrove, swamp, and riverine forests from sea level up to elevations of 2000 m (6561 ft) (Rowe 1996; Supriatna et al. 1996). They prefer forested areas near water and are found in higher densities near riverbanks, lakeshores, or along the seacoast (van Schaik et al. 1996). They preferentially utilize secondary forest, especially if it borders human settlement, where they have access to gardens and farms to crop-raid (Crockett & Wilson 1980; Sussman & Tattersall 1986).

Long-tailed macaques are found in tropical rain forests characterized by warm, humid climate and heavy seasonal rainfall (Supriatna et al. 1996; Umapathy et al. 2003). The rainy season in Southeast Asia lasts from about September to May, with average monthly rainfall between 140 and 300 mm (5.5 and 11.8 in) and with less rainfall from June through August or September (Lucas & Corlett 1991; Yeager 1996; Umapathy et al. 2003). Annual rainfall ranges between 2100 and 4500 mm (6.89 to 14.8 ft) per year (Cannon & Leighton 1994; Melisch & Dirgayusa 1996).


Long-tailed macaques are frugivorous, and on Borneo in Kalimantan, 66.7% of their diet consists of ripe, fleshy fruits while macaques on Sumatra devote an even higher percentage of their diets to fruit (82%) (Yeager 1996; Wich et al. 2002). During times of year when fruit is unavailable, the dry season into the early rainy season, long-tailed macaques focus on other food sources including insects, stems, young and mature leaves, flowers, seeds, grass, mushrooms, invertebrates, bird eggs, clay and bark (Wheatley 1980; Yeager 1996; Son 2003). Where they forage in mangroves, long-tailed macaques spend time consuming crabs and have also been seen eating frogs, shrimp and octopus (Sussman & Tattersall 1986; Son 2003). Most of the time spent looking for and eating food is done below 20 m (65.6 ft) and usually closer to 12 m (39.4 ft) in the lower canopy, understory, and on the ground (Ungar 1996). One reason long-tailed macaques forage at this height is to avoid feeding competition with other sympatric primates. When they inhabit disturbed areas near human settlement, long-tailed macaques quickly learn to raid gardens or crops and beg for food from humans (Lucas & Corlett 1991). They have also been known to enter houses and steal food if humans are not there to frighten or deter them (Gurmaya et al. 1994). One management strategy to decrease the chance of long-tailed macaques becoming agricultural pests is for park officials to feed them and to allow tourists to feed them (Son 2004). In some parts of their range where long-tailed macaques come into contact with tourists at nature reserves up to 22% of their diet can be from provisioned foods (Lucas & Corlett 1991; Son 2003). This strategy is not without costs to both macaques and humans. When humans feed long-tailed macaques, both contact and non-contact aggression increases within and between groups of macaques at the same feeding site. Serious injury or death can occur because of aggressive encounters between long-tailed macaques (Wheatley 1991). Humans are also at risk when feeding long-tailed macaques because the possibility of disease transmission is increased when the two species come into contact. Humans who feed and interact with the macaques can be scratched or bitten and exposed to zoonotic diseases such as simian foamy virus, a virus in the same family as HIV (Jones-Engel et al. 2005). Furthermore, in addition to viruses that have been identified, there is the potential for previously unknown diseases to transfer from the monkeys to the humans who are feeding them, posing a serious health risk to the surrounding communities and beyond (Jones-Engel et al. 2005).

The daily time budget and movement patterns of long-tailed macaques involve traveling, feeding, resting and socializing. Long-tailed macaques have a home range size of about 1.25 km² (.58 mi²) and daily path length varies greatly between 150 and 1900 m (.09 and 1.18 mi) (Wheatley 1980; Rowe 1996). They highly prefer foraging and moving in riverine habitats, and the amount of time spent foraging decreases as they move further from the riverbank. Most of their daily activity happens within 100 m (328 ft) of the river, where resource density is much higher than areas further inland (van Schaik et al. 1996). After leaving their nesting tree between 5:30 and 6:00 a.m., they spend the morning hours feeding heavily while they spend the midday hours resting (Gurmaya et al. 1994). Aggressive interactions between group members are the highest while feeding on fruit, indicating strong competition for this valuable food resource (van Schaik & van Noordwijk 1988). While the group is resting, individuals sleep, play, or groom, with the youngest animals spending time playing while the older animals sleep and groom (Son 2004). After the midday period of rest, long-tailed macaques continue to search for food and feed as they move closer to their sleeping trees. They enter the sleeping trees in the early evening, between 6:00 and 6:30 p.m. and stay there for the night (Gurmaya et al. 1994; Son 2004).

Long-tailed macaques sleep in trees along the river and are particular about choosing their roosting sites. Each group sleeps in its own tree and individuals huddle together when they sleep to maintain body temperature. They sleep toward the edge of the branches near the top or crown of the tree and preferentially choose branches that overhang the river (van Schaik et al. 1996). Long-tailed macaques are excellent swimmers, and this may be a predator avoidance technique: if they are threatened, they simply can escape by dropping to the water and swimming to safety (Rowe 1996; van Schaik et al. 1996). Some predators include pythons, monitor lizards, raptors, large cats, and, in some areas, feral dogs. (Palombit 1992; van Noordwijk & van Schaik 1999). The felid predation risk is so strong in some parts of their range that there is a discernible effect on social structure and group size (van Schaik & van Noordwijk 1985).

Content last modified: January 6, 2006

Written by Kristina Cawthon Lang. Reviewed by Carolyn Crockett.

Cite this page as:
Cawthon Lang KA. 2006 January 6. Primate Factsheets: Long-tailed macaque (Macaca fascicularis) Taxonomy, Morphology, & Ecology . <>. Accessed 2020 July 6.