Macaques

The macaques are successful Old World monkeys (family Cercopithecidae) that are members of the genus Macaca, of which there are some 20 species. Macaques are the most wide-ranging primate species except for humans. One species, M. sylvanus or the Barbary macaque, is found in Morocco, Algeria, and Gibraltar. The other species are found from Afghanistan to Beijing and from Sri Lanka through Indonesia to Japan. M. mulatta, or the rhesus macaque, has the widest distribution and is found from eastern Afghanistan through northern India to southern Vietnam and southern China. Other macaques have a more limited distribution, including those of Sulawesi and Indonesia and M. silenus (the lion-tailed macaque), which is found only in the Western Ghats of India.

Macaques are small to medium-sized monkeys, most of which have a brown or grayish pelage, although a few macaques such as M. nigra have black hair. They have naked faces and ears, and their tails vary in length from nearly no tail (e.g., M. arctoides) to tails that are the length of the body or longer (e.g., M. fascicularis). Macaques are quadrupedal and basically arboreal, although some species such as M. mulatta spend more than half of their time on the ground. Other traits of macaques include cheek pouches and ischial callosities or sitting pads. Their diet is composed mainly of vegetation (fruit, leaves, flowers, and bark) and insects and other invertebrates.

The fossil record of the Old World monkeys is known from the early and middle Miocene, with a group of remains recognized as belonging to two African genera: Victoriapithecus and Prohylobates. These two genera preceded the separation of the two extant subfamilies of Old World monkeys: Colobinae and Cercopithecinae. The Old World monkeys shared a common ancestor with the hominoids (i.e., the apes), diverging during the late Oligocene or early Miocene. Overall, monkey fossils from the Miocene are rather scarce compared with the numerous fossil hominoids. Macaques appear in the fossil record during the late Miocene and early Pliocene, first in Africa and subsequently in Europe and Asia. Today only 1 macaque species still inhabits North Africa (M. sylvanus), 19 species live in Asia, and none is found in Europe. After 5 million years of successful evolution, many species of macaques are facing extinction due to human activities. According to the International Union for Conservation of Nature and Natural Resources, 57% of macaque species are either endangered or vulnerable, and if one adds the near threatened and conservation-dependent species, the number increases to nearly 100% of the macaques potentially facing extinction. Human greed, overpopulation, and lack of compassion are the reasons why the number of macaques is declining worldwide.

The basic macaque social system is called the multimale, multifemale troop in which females remain in their natal troop and males move to a non-natal troop or become solitary. The core of the multimale, multifemale troop is the matrafocal units composed of related females. Males and females have dominance hierarchies, but males (being larger than females and possessing larger canine teeth) are dominant to females. Rank among females is often inherited from their mothers. There is, however, some variation in this basic social system. For example, in rhesus and Japanese macaques, the males are consistently forced out of their natal troops when they reach sexual maturity around 5 years of age, but bonnet macaque males have been known to remain in their natal troops. The dominance hierarchy is generally stronger in those troops fed by humans than in those that survive by foraging on natural vegetation.

Males and females become sexually mature between 4 and 7 years of age. In the wild, macaques rarely live past 20 years of age. With an interbirth interval of 1 to 2 years, a healthy female can expect to produce 5 to 10 offspring over the course of her lifetime and to live long enough to become a grandmother. Sexual behavior is promiscuous, and females mate with both troop and nontroop males. Mating may be observed throughout the monthly menstrual cycle and during the early stages of pregnancy. In addition to heterosexual behavior, masturbation and homosexual behavior have been reported for several species of macaques.

Macaque communication is multimodal in that macaques communicate with facial expressions and body postures, vocalizations, odors, and touching such as grooming and huddling. Macaque communication usually involves dominance, submission, aggression, and reconciliation; mother-infant relationships; warnings of danger; friendly overtures; and messages before, during, and after sexual encounters.

Two epic legends and other myths influence the interaction between people and macaques. The Hindu Ramayana is one such legend in which a monkey god-servant of Lord Rama named Hanuman plays an important heroic role. The other legend is a Chinese epic called Journey to the West in which the Monkey King or Sun WuKong (in Mandarin) is a central character. There are also numerous myths whereby Buddha is reincarnated as a monkey and performs heroic acts. In Asia, there are many variations on these myths and differences in the depictions of the monkeys in the myths. The end result is that macaques are often tolerated and provided with food around temples and other sacred places. Moreover, macaques are often dependent on humans for food because much of their natural habitat has been destroyed. The future of macaques in Asia depends on the good will of the people of Asia and their willingness to provide for their wildlife.

Although the Macaca genus as a whole is monophyletic (i.e., all species share a common ancestor that was also a macaque), some species of macaques seem to be more closely related to each other than to other macaque species. Although a complete consensus has not been reached, the list of genus and species that follows is arranged according to evolutionary relatedness following Groves’s Primate Taxonomy. The species/ groups are based on studies of morphology and genetics. It should be noted, however, that macaques, when given the opportunity, will hybridize and produce fertile offspring.

• Order primates
• Suborder Anthropoidea
• Infraorder Catarrhini
• Superfamily Cercopithecoidea
• Family Cercopithecidae
• Subfamily Cercopithecinae
• Tribe Papionini

Genus and species, common name, and distribution:

Macaca sylvanus group

Macaca sylvanus (Barbary macaque) (Morocco, Algeria, and Gibraltar)

Macaca nemestrina group

Macaca leonina (Northern pig-tailed) (Thailand to Burma into Bangladesh and India)

Macaca nemestrina (pig-tailed macaque) (Malay Peninsula and Borneo)

Macacapagensis (Mentawai macaque) (Mentawai Islands)

Macaca silenus (lion-tailed macaque) (Western Ghats of India)

Sulawesi group

Macaca hecki (Heck’s macaque) (Sulawesi, Indonesia)

Macaca maura (Moor macaque) (Sulawesi, Indonesia)

Macaca nigra (Celebes crested macaque) (Sulawesi, Indonesia)

Macaca nigrescens (Gorontalo macaque) (Sulawesi, Indonesia)

Macaca ochreata (booted macaque) (Sulawesi, Indonesia)

Macaca tonkeana (Tonkean macaque) (Sulawesi, Indonesia)

Macaca fascicularis group

Macaca arctoides (stump-tailed macaque) (Assam, India, though southern China and the northwestern tip of west Malaysia)

Macaca fascicularis (long-tailed or crab-eating macaque) (Burma to southeast Asia, including the Philippines, Vietnam, Malaysia, and Indonesia)

Macaca mulatta group

Macaca cyclopis (Formosan rock macaque) (Taiwan and surrounding islands)

Macaca fuscata (Japanese macaque) (Japan)

Macaca mulatta (Rhesus macaque) (Afghanistan to southern Vietnam to southern China)

Macaca sinica group

Macaca assamensis (Assam macaque) (Northern India through Nepal to Vietnam)

Macaca radiata (bonnet macaque) (Southern India)

Macaca sinica (Toque macaque) (Sri Lanka)

Macaca thibetana (Tibetan or Milne-Edwards’s macaque) (Western India to east-central China)

References:

1. Conroy, G. (1990). Primate evolution. New York: Norton.
2. Falk, D. (2000). Primate diversity. New York: Norton.
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6. Groves, C. (1989). A theory of human and primate evolution. New York: Oxford University Press.
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