Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide


Macaca fascicularis
(crab-eating macaque)



Macaca fascicularis (crab-eating macaque)


  • Last modified
  • 08 November 2018
  • Datasheet Type(s)
  • Invasive Species
  • Host Animal
  • Preferred Scientific Name
  • Macaca fascicularis
  • Preferred Common Name
  • crab-eating macaque
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Metazoa
  •     Phylum: Chordata
  •       Subphylum: Vertebrata
  •         Class: Mammalia
  • Summary of Invasiveness
  • M. fascicularis, the crab-eating macaque, is native to South-East Asia and has been introduced into Mauritius, Palau (Angaur Island), Hong Kong and parts of Indonesia (Tinjil Island and Papua). They are conside...

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Macaca fascicularis (crab-eating macaque); adult. Lake Gardens, Kuala Lumpur, Malaysia. February 2007.
CaptionMacaca fascicularis (crab-eating macaque); adult. Lake Gardens, Kuala Lumpur, Malaysia. February 2007.
CopyrightPublic Domain - Released by Gary Houston/via wikipedia - CC0
Macaca fascicularis (crab-eating macaque); adult. Lake Gardens, Kuala Lumpur, Malaysia. February 2007.
AdultMacaca fascicularis (crab-eating macaque); adult. Lake Gardens, Kuala Lumpur, Malaysia. February 2007.Public Domain - Released by Gary Houston/via wikipedia - CC0


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Preferred Scientific Name

  • Macaca fascicularis (Raffles, 1821)

Preferred Common Name

  • crab-eating macaque

Other Scientific Names

  • Macaca irus F. (Cuvier, 1818)

International Common Names

  • English: long-tailed macaque

Summary of Invasiveness

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M. fascicularis, the crab-eating macaque, is native to South-East Asia and has been introduced into Mauritius, Palau (Angaur Island), Hong Kong and parts of Indonesia (Tinjil Island and Papua). They are considered to be invasive, or potentially invasive, throughout their introduced range and management may be needed to prevent them from becoming invasive in areas such as Papua and Tinjil. They are opportunistic mammals and reach higher densities in degraded forest areas and habitats disturbed by humans. They have few natural predators in their introduced ranges. M. fascicularis impact native biodiversity by consuming native plants and competing with birds for fruit and seed resources. In addition, they facilitate the dispersal of seeds of exotic plants. M. fascicularis may also impact on the commercial sector through consuming agriculturally important plant species and damaging crops. This species has been nominated as among 100 of the "World's Worst" invaders. 

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Metazoa
  •         Phylum: Chordata
  •             Subphylum: Vertebrata
  •                 Class: Mammalia
  •                     Order: Primates
  •                         Family: Cercopithecidae
  •                             Genus: Macaca
  •                                 Species: Macaca fascicularis

Notes on Taxonomy and Nomenclature

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Some primate taxonomists consider M. fascicularis to be part of a species group (the fascicularis group) which comprises four species: M. mulatto, M. cyclopis, M. fuscata as well as M. fascicularis (e.g. Fooden and Albrecht, 1999). M. fascicularis has been divided into subspecies. The National Primate Research Center (2012) identifies the following 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.


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Upper parts dark brown with light golden brown tips; under parts light grey. The tail is dark grey/brown. Crown hairs are directed backwards, sometimes forming a short crest on the mid-line. Skin is black on the feet and ears, and the muzzle is light greyish-pink. Eyelids often have prominent white markings, and white spots are sometimes seen on the ears. No perineal swelling. Males 3.5kg - 8.3kg; Females 2.5kg - 5.7kg.


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Native Range: Mainland South-East Asia including southern Burma, eastern Thailand, Cambodia, southern Laos and Vietnam, Malaysia, Philippines, and Indonesia (Sumatra, Borneo, Java, Bali, and eastern Lesser Sunda Islands).
Known introduced range: Mauritius, Palau (Angaur Island), Hong Kong, Papua New Guinea, and parts of Indonesia (Tinjil Island and Papua).

Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes


BangladeshPresentNativeJiang et al., 2008
Brunei DarussalamPresentNativeJiang et al., 2008
CambodiaPresentNativeJiang et al., 2008
ChinaPresentCAB ABSTRACTS Data Mining 2001
-GuangxiPresentCAB ABSTRACTS Data Mining 2001
-Hong KongPresentIntroduced1950s/1960s Invasive ISSG, 2011
East TimorPresentNativeIUCN, 2012
IndiaPresentPresent based on regional distribution.
-Andaman and Nicobar IslandsPresentNativeJiang et al., 2008
IndonesiaPresentNativeIUCN, 2012Native to Sumatra, Java, Bali and eastern Lesser Sunda islands. Non-native in Tnjil Island and Papua. (GISD datasheet, 2012).
-Irian JayaPresentIntroduced1910-1970s Not invasive ISSG, 2011
LaosPresentNativeIUCN, 2012
MalaysiaPresentCAB ABSTRACTS Data Mining 2001
PhilippinesPresentCAB ABSTRACTS Data Mining 2001
SingaporePresentNativeJiang et al., 2008
ThailandPresentNativeJiang et al., 2008
VietnamPresentNativeJiang et al., 2008


MauritiusPresentIntroduced1500-1600 ? Invasive ISSG, 2011

South America

BrazilPresentCAB ABSTRACTS Data Mining 2001


PalauPresentIntroduced1870-1914 Invasive ISSG, 2011
Papua New GuineaPresentIntroducedIUCN, 2012


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Crab-eating macaques inhabit a wide range of habitats including riverine, secondary and primary forest, forest periphery, mangrove and nipa swamp, coastal forest, and urban and agricultural settings, in both their native and introduced range. They have a preference for secondary habitats which have been disturbed by human activity and are highly adaptive to new environments. They occur from sea level to 1200m.  They have home range sizes of around 1.25km2 and distance of daily movements can vary between 150 and 1900m (National Primate Research Center, 2012).

Habitat List

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Terrestrial – ManagedCultivated / agricultural land Present, no further details
Managed forests, plantations and orchards Present, no further details
Disturbed areas Present, no further details
Urban / peri-urban areas Present, no further details
Terrestrial ‑ Natural / Semi-naturalNatural forests Present, no further details
Natural grasslands Present, no further details
Riverbanks Present, no further details
Scrub / shrublands Present, no further details

Biology and Ecology

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Herbivory: Fruit and seeds make up 60 - 90% of the dietary intake of macaques. They will also eat leaves, flowers, roots and bark.
Carnivory: They prey on vertebrates (including bird chicks and nesting female birds) and invertebrates. In Mauritius they have been recorded eating bird eggs.

M. fascicularis is an “opportunistic omnivore” exploiting a very wide variety of foods. It is also a known nest predator, taking bird eggs and possibly adult birds. It is suspected of consuming several rare species of lizard on Mauritius. It has manipulable hands allowing it to open fruit casings and nuts. It can exploit a great range of food items, helping it to compete strongly for food resources (Kemp and Burnett, 2003).

Placental. Sexual. Polyoestrous. May breed at any time of year. They typically give birth to single young, rarely twins, every two years.

Lifecycle stages
Gestation 167 days. Lactation 14-18 months. Duration of oestrus 11 days. Females become sexually mature at 4 years and live up to 25 years on average; up to 37 years in captivity. Sex ratios within troops are usually biased towards females.

Notes on Natural Enemies

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Natural predators of crab-eating macaques (Macaca fascicularis) include large carnivores (panthers and sun-bears in Java), snakes and possibly large raptors.

Means of Movement and Dispersal

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Introduction pathways to new locations
Acclimatisation societies
Landscape/fauna "improvement"
Pet trade
: In the 16th century long-tailed macacwques were introduced by Portuguese or Dutch sailors from Sumatra or Java into Mauritius where they have readily adapted to flora entirely different from that of Asia (Sussman et al., 2011).

Local dispersal methods
Escape from confinement: The risk of pet crab-eating macaques escaping and forming new populations is significant as many people import these animals to keep or sell as pets (Kemp and Burnett, 2003).
Natural dispersal (local): The home range of crab-eating macaques varies greatly depending on the location and whether they are in their native range or an introduced range. In their native range the home range size may vary from between 50 hectares and 100 hectares, although the National Primate Conservation Center (2012) give 1.25km2 = 125ha. The average troop home range in their introduced range is estimated to be only 800 m² in Mauritius (Sussman and Tattersall, 1986, Carter and Bright, 2002). In their introduced range in Papua (Indonesia) the home range size may vary between 3 hectares and 22 hectares.


    Pathway Causes

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    CauseNotesLong DistanceLocalReferences
    Acclimatization societies Yes Yes
    Escape from confinement or garden escape Yes
    Military movements Yes Yes
    Pet trade Yes Yes

    Impact Summary

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    Biodiversity (generally) Negative
    Crop production Negative
    Human health Negative


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    M. fascicularis may negatively impact biodiversity by eating the eggs and chicks of endangered forest birds. They compete with native birds for resources such as fruits. They may aggravate the negative effects of exotic plant species by consuming their fruits and aiding dispersal of their seeds. Macaques feed on sugar cane and other crops, affecting agriculture and livelihoods, and can be aggressive towards humans. Macaques may carry potentially fatal human diseases, including B-virus. See the Center for Disease Control information on B virus.

    The absence of predators or mammalian competitors in Mauritius has allowed them to thrive there, where they are a pest to agriculture and are thought to have contributed to the extinction of native bird species (Malaivijitnondi and Hamada, 2008).

    Risk and Impact Factors

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    • Negatively impacts agriculture
    • Negatively impacts human health
    • Threat to/ loss of native species


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    In their natural range, crab-eating macaques are occasionally used as a food source for some indigenous forest dwelling peoples. In Mauritius, they are seen as sacred animals, potential tourist attractions and are exported for medical research (Sussman et al., 2011). They are sold to the pharmaceutical industry with a value of approximately US$1500 per individual. In Angaur, Palau they are sold as pets. China, Indonesia, Mauritius, Vietnam and the Philippines are the largest exporters of M. fascicularis (Foley and Shepherd, 2011). M. fascicularis is one of the most commonly used primates in medical research.

    Uses List

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    • Pet/aquarium trade
    • Research model

    Human food and beverage

    • Food

    Prevention and Control

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    Preventative measures: Plantations of Japanese red cedar (Cryptomeria japonica) appear to provide protection to native birds (and eggs) from the predation and scavenging of macaques. Quarantine measures need to be more effective in places such as Papua (Indonesia) to prevent the range expansion of the current population.

    Physical: In Mauritius, live-trapping has been carried out for export and research. Socio-religious reasons may mean this solution is not appropriate. Animals may become trap-shy. Local communities in Papua and Palau have hunted macaques with some success.

    Biological: The immuno-vaccine Porcine Zona Pellucida (PZP) (which causes infertility in females) is currently being trialled in Hong Kong to investigate its use as a population control.


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    Gumert MD, Fuentes A, Jones-Engel L, 2011. Monkeys on the edge: Ecology and management of long-tailed macaques and their interface with humans. Cambridge: Cambridge University Press

    References from GISD

    Bertram, B. and Ginsberg, J. 1994. Monkeys in Mauritius: Potential for Humane Control (Confidential report by the Zoological Society of London commissioned by the RSPCA): 25.

    Bomford, M., 2003. Risk Assessment for the Import and Keeping of Exotic Vertebrates in Australia. Bureau of Rural Sciences, Canberra.

    Bright, P. and Carter, S. 1999. Exotic Vegetation as a Refuge From Predation for Endangered Mauritian Birds. British Ecological Society.

    Carter, S.P. and Bright, P.W. 2002. Habitat Refuges as Alternatives to Predator Control for the Conservation of Endangered Mauritian Birds. In Veitch, C.R. and Clout, M.N. (eds.) Turning the Tide: the Eradication of Invasive Species: 71 - 78. IUCN SSC Invasive Species Specialist Group: Switzerland and Cambridge.

    Cheke, A.S. 1987. An Ecological History of the Mascarene Islands, With Particular Reference to Extinctions and Introductions of Land Vertebrates. In Diamond, A.W., Cheke, A.S. and Elliot, H.F.I. (eds.) Studies of Mascarene Island Birds, for the British Ornithologist's Union. Cambridge University Press: Cambridge.

    Courchamp, F., Chapuis, J-L. and Pascal, M. 2002. Mammal Invaders on Islands: Impact, Control, and Control Impact, Biological Reviews 78: 347 - 383.

    deRuiter, J.R. 1992. Capturing Wild Long-tailed Macaques (Macaca fascicularis), Folia Primatology 59: 89 - 104.

    IUCN Red List of Threatened Species.

    IUCN/SSC Invasive Species Specialist Group (ISSG)., 2010. A Compilation of Information Sources for Conservation Managers Involved in the Prevention, Eradication, Management and Control of the Spread of Invasive Alien Species that are a Threat to Native biodiversity and Natural Ecosystems.

    Kemp, N.J. and Burnett, J.B. 2003. A Biodiversity Risk Assessment and Recommendations for Risk Management of Long-tailed Macaques (Macaca fascicularis) in New Guinea (final report). Indo-Pacific Conservation Alliance: Washington.

    Kyes, R.C., Sajuthi, D., Iskandar, E., Iskandriati, D., Pamungkas, J., and Crockett, C.M. 1998. Management of a Natural Habitat Breeding Colony of Long-tailed Macaques, Tropical Biodiversity 5 (2).

    Sussman, R.W. and Tattersall, I. 1980. A Preliminary Study of the Crab-eating Macaque Macaca fascicularis in Mauritius, The Maurutius Institute Bulletin 9 (1): 31 - 51.

    Sussman, R.W. and Tattersall, I. 1981. Behavior and Ecology of Macaca fascicularis in Mauritius: A Preliminary Study, Primates 22(2): 192 - 205.

    Sussman, R.W. and Tattersall, I. 1986. Distribution, Abundance, and Putative Ecological Strategy of Macaca fascicularis on the Island of Mauritius, Southwestern Indian Ocean, Folia primatologica 46: 28 - 43.


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    Foley HE; Shepherd CR, 2011. Trade in long-tailed macaques. In: Monkeys on the edge: Ecology and management of long-tailed macaques and their interface with humans [ed. by Gumert, M. D. \Fuentes, A. \Jones-Engel, L.]. Cambridge, UK: Cambridge University Press, 380 pp.

    Fooden J; Albrecht GH, 1999. Tail-Length Evolution in Fascicularis-Group Macaques (Cercopithecidae: Macaca). International Journal of Primatology, 20 (3): 431-440.

    Gumert MD; Fuentes A; Jones-Engel L, 2011. Monkeys on the edge: Ecology and management of long-tailed macaques and their interface with humans. Cambridge, UK: Cambridge University Press, 380.

    ISSG, 2011. Global Invasive Species Database (GISD). Invasive Species Specialist Group of the IUCN Species Survival Commission.

    IUCN, 2012. IUCN Red List of Threatened Species. Macaca fascicularis.

    Jiang Z; Meng Z; Zeng Y; Wu Z; Zhou Z, 2008. CITES non-detrimental finding case study for the exporting of crab-eating macaques. (Macaca fascicularis) from China. DF WORKSHOP CASE STUDIES WG 5 - Mammals CASE STUDY 5 Macaca fascicularis.

    Kemp NJ; Burnett JB, 2003. Final Report: A biodiversity risk assessment and recommendations for risk management of Long-tailed Macaques (Macaca fascicularis) in New Guinea. Indo-Pacific Conservation Alliance (IPCA).

    Malaivijitnondi S; Hamada Y, 2008. Current Situation and Status of Long-tailed Macaques (Macaca fascicularis) in Thailand. The Natural History Journal of Chulalongkorn University 8(2): 185-204.

    National Primate Research Center, 2012. Primate Info Net. Library and Information Service. National Primate Research Center University of Wisconsin-Madison. Long-tailed macaque Macaca fascicularis.

    Sussman RW; Shaffer CA; Guidi L, 2011. Implications for macaque-human interactions and for future research on long-tailed macaques. In: Monkeys on the edge: Ecology and management of long-tailed macaques and their interface with humans [ed. by Gumert, M. D. \Fuentes, A. \Jones-Engel, L.]. Cambridge, UK: Cambridge University Press, 380 pp.


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      Reviewed by: Neville Kemp, Indo-Pacific Conservation Alliance.
      Compiled by: Steve Carter, Ecologist, Wildlife Disease Ecology Team, Central Science Laboratory UK & IUCN/SSC Invasive Species Specialist Group (ISSG)
      Last Modified: Thursday, January 11, 2007

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