Formosan rock macaque (Macaca cyclopis)

Also known as: Formosan rock monkey, Taiwan macaque, Taiwanese macaque
French: Macaque De Formose
Spanish: Macaca De Formosa
GenusMacaca (1)
SizeMale head-and-body length: 45 - 54 cm (2)
Female head-and-body length: 36 - 45 cm (2)
Male tail length: 36 - 45 cm (2)
Female tail length: 38 - 40 cm (2)
Male weight: 6 - 9 kg (2)
Female weight: 4 - 6 kg (2)


This medium-sized, quadrupedal monkey has a soft, dark grey to brown coat, which is greyer in winter and a drabber olive-brown colour in summer (4) (5). The hairless face is salmon-pink and includes large cheek pouches that are used to carry food whilst foraging (4) (5).

The Formosan rock macaque is native to the island of Taiwan, where it primarily occupies the mountainous areas in the north-eastern and south-western parts of the island (4) (5). Although the species is thought to have once been associated with coastal areas, it is now largely confined to inland hills because of human activity (5). This macaque has also been introduced to a few small islets in Japan, where it hybridises with the Japanese macaque (M. fuscata) (6).

Primarily found in mixed coniferous-hardwood temperate forest, as well as bamboo and grassland, at elevations between 100 and 3,600 m above sea level (5).

The Formosan rock macaque has a multimale-multifemale social system, with groups averaging around 45 individuals occupying partially-overlapping territories (5) (7). However, the recent decline in numbers has meant that groups are often much smaller, typically ranging between two and ten individuals, and may more closely resemble a unimale system (4) (5). While females remain in their natal group, existing within a female hierarchy, males disperse shortly after adolescence, at around five years of age (5) (7). However, relatively low-ranking females have been observed splitting from their natal group to form new troops where they may find higher status. Low-ranking sub-adult and old adult males within a troop are peripheralised by the dominant alpha male, and often form coalitions. Most challenges for the alpha-male position are made during the breeding season, when competition for access to sexually receptive females is fierce (7).

The breeding season is between November and January, with births occurring from April through to June, peaking from mid-April to mid-May (5) (7). Females start to breed at between four and five years of age (7), after which they usually produce a single offspring every other year, with older females giving birth every year (5). Gestation lasts around 165 days and, in most macaques, nursing lasts about a year, with the majority of parental care provided by the mother. Young are usually completely independent after two years, although females often retain life-long associations with their mother and other female kin (5).

Formosan macaques are a diurnal, ground-dwelling species, comfortable in areas with few or no trees. A variety of foods are consumed, including fruits, leaves, berries, seeds, buds, young shoots, insects and small vertebrates, and these macaques reportedly also raid crops (5).

Like so many primates, the Formosan rock macaque has drastically declined in numbers at the hands of their close relative, humans (8). Reports from 1989, when the Wildlife Conservation Law was enacted, state that the very survival of this species was in serious jeopardy, with at least 3,000 a year being killed for food, medicinal preparations, and taken as pets and for research (5) (8). Sadly, macaques’ similarity to humans in physiology and disease susceptibility has made them a popular subject of biological, medicinal and psychological research (5). Additionally, this species was being exploited for trade of curiosities, such as ashtrays made from their skulls, sold in night markets (8). Human encroachment has also heavily impacted population numbers through habitat destruction, restricting the Formosan rock macaque primarily to remote inland highlands (5).

Throughout the 1990s, following the enactment of the Wildlife Conservation Act, the Formosan rock macaque was the focus of Taiwan’s intensive and highly successful conservation efforts, which have significantly increased population numbers. However, the larger, rebounded population of these macaques has created some new problems in their relationship with humans. For example, farmers have begun to complain that the species is a serious crop pest and have tried strategies from dogs to firecrackers to traps to try to deal with the thieves. In addition, in areas where tourists regularly feed the macaques, people have been attacked by monkeys demanding food, and some macaques have become over-dependent on human feeding. Thus, although the growing numbers of Formosan rock macaques is a great conservation success story, the equally growing tension between humans and monkeys highlights the need for conservation management to consider the wider ecological picture, if they are to create a balanced, harmonious and sustainable relationship between these two primate species (8).

For more information on the Formosan rock macaque see:


  1. IUCN Red List (June, 2009)
  3. CITES (November, 2006)
  4. Primate Behaviour (November, 2006)
  5. Animal Diversity Web (November, 2006)
  6. Conservation International: Hotspots Revisited (November, 2006)
  7. Hsu, M.J. and Lin, J. (2001) Troop Size and Structure in Free-ranging Formosan Macaques (Macaca cyclopis) at Mt. Longevity, Taiwan. Zoological Studies, 40(1): 49 - 60. Available at:
  8. Formosan macaque revival raises ecological questions – Taiwan Journal, Jan 06, 2004 (November, 2006)