PIN still needs volunteers, including students of primatology, who are working directly with species and also peer reviewers to help us update our fact sheets. In the meantime, we welcome readers to send updates for consideration. We will evaluate suggestions with experts, then consider adding these updates in context and in parentheses, along with “This content is provided as a courtesy to PIN readers and is not part of the original peer-reviewed fact sheet. Current date/year.” We advise our readers to use our fact sheets as just one source of information and to always research additional sources.
Species: M. nigra
Other names: black ape, Celebes crested macaque, Celebes ape, Celebes macaque, crested black macaque, Sulawesi crested black macaque, Sulawesi macaque; cynopithèque nègre or macaque des célèbes (French); macaca negra (Spanish); celebesmakak, svart sulawesimakak, or svartapa (Swedish)
Total population: 106,000
Gestation: 5.8 months (174 days)
Height: 520 to 570 mm (M), 445 to 570 mm (F)
Weight: 9.9 kg (M), 5.5 kg (F)
Although they are monkeys, crested black macaques are sometimes wrongfully referred to as apes because of their extremely truncated tails (Groves 2001). Usually one of the best ways to differentiate between a monkey and an ape is to look for the presence of a tail, but this is difficult with crested black macaques because their short tails are difficult to see.
Crested black macaques have entirely black faces and bodies except for the striking bright pink coloration of their ischial callosities, leathery, hairless pads on the rump. The hair on their heads forms a long, backward, and upward-directed pointy crest and they have prominent, bony cheek ridges and a shelf-like brow bone (Rowe 1996; Groves 2001). They have short tails that are only about 20 mm (.79 in) long (Bynum 1999). Crested black macaques are sexually dimorphic, with males almost twice the size of females: males measure between 520 and 570 mm (1.71 and 1.87 ft) and weigh 9.9 kg (21.8 lb), on average, while females measure 445 to 570 mm (1.46 to 1.8 ft) and only weigh 5.5 kg (12.1 lb), on average (Rowe 1996; Singh & Sinha 2004). In addition to larger body size, male crested black macaques have enlarged canine teeth compared to females. They use these in aggressive encounters with other males while competing for access to females and during intergroup encounters while defending food resources (Hadidian 1980; Kinnaird & O’Brien 2000). Crested black macaques are semi-terrestrial, spending time moving on the ground and through the trees by quadrupedal walking (Rowe 1996).
CURRENT RANGE MAPS (IUCN REDLIST):
Wild crested black macaques are found only on two islands in Indonesia. They are restricted to the tip of the northeastern-most peninsula of Sulawesi and on an island 345 miles from Sulawesi, Pulau Bacan, where they were introduced by humans in 1867 (Rosenbaum et al. 1998a). Though these populations have been geographically separated for almost 150 years, they exhibit the same morphological, ecological, and behavioral patterns (Rosenbaum et al. 1998a). On Sulawesi, they are found in Tangkoko Batuangus-Dua Sudara, Gunung Ambang, and Gunung Manembonembo Nature Reserves as well as Bunaken Marine National Park (Bynum et al. 1999). The majority of the population is found in Tangkoko and it is here where most of the field research has been conducted. Research on Bacan has been conducted at Gunung Sibela Nature Reserve (Rosenbaum et al. 1998a).
Until recently there were few field research studies conducted on crested black macaques in the wild and the result is little published information about behavior, ecology, social organization, and reproduction. This pattern has been reversed in recent years and some of the researchers working with this species include Timothy O’Brien, Margaret Kinnaird, and Barry Rosenbaum.
The northern peninsula of Sulawesi is highly seasonal and characterized by its volcanic geography. Tangkoko ranges over an area with elevations from sea level to 1351 m (4432 ft). Within the reserve, landscape patterns include severely disturbed and burned areas, abandoned regenerating gardens, secondary forest, and primary forest (O’Brien & Kinnaird 1997). Throughout their entire range on Sulawesi and some of their range on Bacan, crested black macaques live in areas of habitat disturbance ranging from small gardens surrounded by primary forest to clear-cut areas (Rosenbaum et al. 1998b). The severity of habitat disturbance changes the floral composition of the landscape, and macaques are found in differing densities according to disturbance (Rosenbaum et al. 1998b). Annual rainfall in this region is between 1550 and 2400 mm (3.77 and 7.87 ft) with the majority of rain falling between October and May. The temperature is fairly constant throughout the year, ranging from 21.7° C (71° F) to 34.4° C (94° F) at the coolest and hottest points in the year, respectively (O’Brien & Kinnaird 1997). The temperature and climate on Bacan is similar to that on Sulawesi and vegetational communities on Bacan range from lowland tropical forest to montane rainforest at the higher elevations. Gunung Sibela, the nature reserve where crested black macaques are studied, is located at an elevation of 2110 m (6922 ft) (Rosenbaum et al. 1998a).
Crested black macaques use a variety of habitats including lowland and montane primary forests, early and mature secondary forests, mangroves, areas of cultivation surrounded by primary and secondary forests, actively logged forests, and areas of dense human habitation and agriculture (Rosenbaum et al. 1998a). Though they are found in actively logged forests, they are found in lower densities in these highly disturbed areas (Rosenbaum et al. 1998a). Crested black macaques spend their days traveling, feeding, foraging, socializing, and resting. Of these activities, they spend 59% of their time traveling, foraging, and feeding and the remaining part of their day is spent resting and socializing (O’Brien & Kinnaird 1997). Socializating occurs in the morning and midday, and resting occurs in the mid to late afternoon. Traveling, feeding, and foraging are distributed evenly throughout the day (O’Brien & Kinnaird 1997). They are primarily terrestrial, spending more than 60% of their day on the ground foraging and socializing. Crested black macaques are mainly frugivorous, spending 70% of their time feeding on fruits, but they consume a huge variety of foods including seeds, leaves, flowers, pith, herbs, grass seeds, fungus, bird eggs, birds, and small vertebrates such as lizards and frogs (O’Brien & Kinnaird 1997). They are not seen above 1250 m (4101 ft) and the majority of observations occur below 700 m (2296 ft). Elevation restrictions are probably linked to low levels of fruit abundance at higher altitudes on Bacan. At Tangkoko, they do not range above 1100 m (3608 ft) (Rosenbaum et al. 1998a).
In Tangkoko, group size varies between 27 and 97 individuals, and groups have overlapping home ranges. Average monthly home range size varies from .47 to 3.48 km² (.18 to 1.34 mi²) and the average daily path length is 2388 m (1.48 mi) but varies greatly depending on access to primary forest (O’Brien & Kinnaird 1997). When crested black macaques have access to primary forest, they spend much less time traveling, presumably because of the higher quality of the habitat and higher abundance of fruit in these areas. Additionally, during periods of highest fruit abundance, crested black macaques do not travel as far each day (Kinnaird & O’Brien 2000). Group size on Bacan is much smaller with groups having, on average, 20 individuals (Rosenbaum et al. 1998a). Population densities in Tangkoko average about 30 individuals per square kilometer (19 per square mile), though in unprotected areas of Sulawesi they are significantly lower, with only about five individuals per square kilometer (3 per square mile)(Feistner 2000). On Bacan, densities of crested black macaques are as high as 170 animals per square kilometer (106 per square mile) in primary forest, but in logged forest, densities are considerable lower, with 133 individuals per square kilometer (82 per square mile)(Rosenbaum et al. 1998b).
Content last modified: February 2, 2006
Cite this page as:
Cawthon Lang KA. 2006 February 2. Primate Factsheets: Crested black macaque (Macaca nigra) Taxonomy, Morphology, & Ecology . <http://pin.primate.wisc.edu/factsheets/entry/crested_black_macaque/taxon>. Accessed 2020 July 30.
For individual primate species conservation status, please search the IUCN Red List.
Also search the current scientific literature for primate conservation status (overall as well as for individual species), and visit CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora).
Conservation information last updated in 2006 follows, for comparison:
The most serious conservation concerns facing crested black macaques on Sulawesi are habitat destruction and fragmentation and hunting. The total population is estimated to be between 4000 and 6000 individuals. On Bacan, where the human population density is lower, timber extraction is not as widespread, and the people traditionally do not hunt monkeys. The result is a booming population, with estimates ranging up to 100,000 (Rosenbaum et al. 1998b; Bynum et al. 1999).
CONSERVATION THREATS & POTENTIAL SOLUTIONS
Threat: Human-Induced Habitat Loss and Degradation
On Sulawesi, the highest densities of human populations are concentrated in the far southwest and northeast corners of the island. In the northeast, the only part of Sulawesi where crested black macaques can be found, the dense human population has directly affected forest structure in lowland areas. Conversion of forest for subsistence and commercial agriculture, collection of forest products, road systems, and extraction of timber and minerals have severely degraded and fragmented the forests on which crested black macaques rely (Bynum et al. 1999). Cloves, coconut, and coffee plantations for commercial harvest dominate northern Sulawesi and replace primary forest with monocultures that are virtually useless to crested black macaques. Even subsistence gardens at high enough densities threaten these monkeys; the increasing human population needs increasing land to grow crops and as individual gardens are cleared, forests become more fragmented (Bynum et al. 1999). The collection of forest products in nature reserves includes wood, rattan (a multi-purpose fiber) and palm leaves. In forests bordered by areas of high human population density, the collection of these products can seriously degrade primary forest quality (O’Brien & Kinnaird 1996; Rosenbaum et al. 1998b). The extensive network of roads being built in this region to accommodate the growing human population only serves to exacerbate the problem. As areas of pristine forest are cleared and roads are cut through tracts of forest, people have easier access to previously untouched resources. Though the levels of deforestation are lower than other areas of Indonesia because access to higher levels is difficult due to the steep volcanic slopes, the areas where these macaques are found are quickly being destroyed (Bynum et al. 1999).
Protected areas on Sulawesi include Tangkoko Batuangus-Dua Sudara, Gunung Ambang, and Gunung Manembonembo Nature Reserves as well as Bunaken Marine National Park. The largest and densest population of crested black macaques occurs at Tangkoko and while they are found in other protected areas, densities are much lower. There are also a number of protected forests, but these are under heavy resource pressures and are not thought to contain crested black macaques (Bynum et al. 1999). Protected areas on Sulawesi can be considered “paper parks,” in which resource use within the parks is prohibited by legislation, but no structured system of stopping resource extraction exists (Bynum et al. 1999). There is little doubt that the only viable population of crested black macaques on Sulawesi exists in Tangkoko because areas outside this reserve, even in other reserves, are severely compromised (Rosenbaum et al. 1998b).
Enforcement of laws prohibiting agriculture and extraction of resources from protected areas must be implemented immediately if crested black macaques are to be protected in the most important parts of their range (Bynum et al. 1999). Human population densities are only going to increase in the future, and unless effective enforcement of protected area status is activated, the growing human population will continue to destroy crested black macaque habitat. Education programs about the unique nature of crested black macaques for people surrounding reserves as well as programs allowing only limited extraction of forest products may decrease pressure on parks (Bynum et al. 1999). A more radical approach is confiscation of forest products by government officials and subsequent prosecution of violators. Another approach might include ecotourism, which gives a different economic value to forest products for local people and in some instances, may encourage protection by local people. If people glean profits from having undamaged parks which tourists pay to enjoy, there may be an incentive to reduce resource consumption and increase protection of the habitat (Kinnaird pers. comm.).
Reducing mechanized commercial logging may also have an impact on sustaining habitat for the crested black macaque. Rather than using machines to clear-cut areas, which is exceptionally destructive to wide tracts of land, the business of logging for domestic use could focus on more sustainable techniques such as selective logging. Convincing logging companies to do this may be difficult, but because the logs extracted are sold primarily within Indonesia, not exported, community-based efforts focusing on the endemism of crested black macaques could turn consumer attitude toward supporting sustainable logging (Rosenbaum et al. 1998b). That is, Indonesian buyers of timber have more stake in the sustainable and responsible harvest of logs than do foreign buyers who have no connection to the native flora and fauna at risk from mechanized logging.
Threat: Harvesting (hunting/gathering)
Hunting of crested black macaques is an even more severe threat to their survival than habitat destruction (Lee 1995; Rosenbaum et al. 1998b; Bynum et al. 1999; Kinnaird pers. comm.). Among Christians on Sulawesi, monkey meat is a traditional food and a delicacy for special occasions including Christmas dinner and other celebrations (Rosenbaum et al. 1998b). Among Indonesian Muslims, monkeys are not eaten because of religious prohibition, but even in areas where the human population is predominantly Muslim, hunting is still a problem. In these areas, conflicts with farmers lead to killing or trapping crested black macaques and selling them as pets (Rosenbaum et al. 1998b; Bynum et al. 1999).
Because of the social structure of crested black macaques, the serious potential to eradicate large numbers in a small period of time is great. It is easy and inexpensive for hunters to capture several macaques at a time because they only have to find one group to have access to dozens of animals. Additionally, because it is a delicacy, monkey meat is in demand throughout the year and hunters exploit the market demand year-round (Lee 1995). Indonesian law prohibits hunting in protected areas, but there is essentially no protection afforded to macaques because reserve personnel are unable to patrol all areas under their care. Furthermore, there is evidence that only in the most central part of Tangkoko are crested black macaques protected from poachers; in all other areas of the reserve and other reserves in Sulawesi, hunters are free to track and kill any animals (Bynum et al. 1999).
Better enforcement and education programs focused on changing the traditional and cultural attitudes of Christians in Sulawesi is necessary to decrease hunting pressure on crested black macaques (Bynum et al. 1999). In the decade from 1990 to 2000, only one prosecution for trade of protected macaques occurred. The resulting actions were only taken because of the publicity engendered by a researcher at Tangkoko who caught two men with 11 dead macaques and reported them to the local police. After two months of inaction by the police, the researcher created publicity in local newspapers and magazines. After four more months, the men were finally tried and sentenced. They spent six months in prison (Clayton & Milner-Gulland 2000). Both men that were prosecuted claimed to be unaware of the prohibitions against hunting crested black macaques. While it is difficult to surmise if this was the truth, certainly education programs could ensure that local people know and understand Indonesian law and the potential punishment for hunting protected species. Clearly enforcement is an issue, given that this single case in a decade was only brought before the court because of the action of one researcher. Even if enforcement was impossible throughout the year, given that monkey meat is known to be in especially high demand around Christmas, local officials could spend more time during this part of the year patrolling for and prosecuting poachers (Clayton & Milner-Gulland 2000). Another potential solution is to replace hunting with another income-generating activity for hunters. On average, a hunter receives only US$1.36 for each macaque sold at market; replacing this income with another more sustainable source of money could potentially decrease the incentive to hunt macaques (Clayton & Milner-Gulland 2000).
Crested black macaques come into contact with humans when the macaques raid crops adjacent to areas of forest. They are considered agricultural pests because in large groups, they can strip a garden of all harvestable fruit in one visit and can destroy the potential for future growth. Understandably, tolerance for this crop-raiding behavior is low and local people often set traps and snares on the borders of their gardens to catch offending crested black macaques (Rosenbaum et al. 1998b; Bynum et al. 1999). As human populations grow and the abundance of subsistence gardens increases, the destruction of primary forest fruit resources will also increase and this problem is likely to worsen and affect even more macaques (Bynum et al. 1999).
There are known crops that are not palatable to crested black macaques, including cloves, rice, and pepper. Strategically planting these crops at the border of gardens or in areas dense in subsistence agricultural production could decrease crop damage done by macaques and reduce persecution (Bynum et al. 1999). Furthermore, if this planting of deterrent crops is coupled with community education programs, tolerance of crested black macaques may increase and fewer traps and snares will be set.
Threat: Natural Disasters
Climate change has played a significant role in the loss of crested black macaques and could have significant effects in the future as population size dwindles. Widespread drought following the El Niño/Southern Oscillation of 1997-98 led to the largest fire disaster ever observed and resulted in the burning of millions of acres in this region of Southeast Asia. Though normally not vulnerable to fires even during drought, tropical forests that are severely logged are at high risk for destruction by wildfires (Siegert et al. 2001). The use of fire is widely employed as a tool to clear land for commercial and subsistence agriculture as well as hunting in some areas of Indonesia. During periods of severe drought brought on by El Niño, the logged forests were particularly sensitive to fire activity and many fires started by local people resulted in uncontrollable forest fires that burned millions of acres and undoubtedly killed forest-dwelling animals including crested black macaques (Anonymous 1997; Siegert et al. 2001).
Though there is no solution to drought or its underlying causes, some important management techniques can be implemented to decrease the likelihood of another El Niño event decimating the crested black macaque population. Decreasing logging activity in primary forests is necessary and would decrease the chance of fire affecting the forests. Furthermore, education and giving incentives to corporations and local people to change their land clearing techniques would reduce the opportunity for fires to get out of control.
Threat: Changes in Native Species Dynamics
Though their ranges do not overlap, the ranges of crested black macaques and another species, M. nigrescens border each other. Examinations of monkeys coming from this border region led to some speculation that there was a low level of hybridization among these species (Watanabe & Matsumura 1991). No genetic tests were conducted and as this assertion was based on the physical characteristics of only a few individuals and it is unlikely that these specimens were hybrids (Groves 2001). Furthermore, discrimination tests conducted on all seven species of macaques (Macaca) on Sulawesi were conducted in captivity and showed that each species had a definite, and strong, response to, and visual preference for, members of its own species, further decreasing the likelihood that hybridization affects crested black macaques in the wild (Fujita & Watanabe 1997).
Threat: Intrinsic Factors
There is no published data on the genetic diversity of wild crested black macaques to evaluate if they are threatened by genetic drift or inbreeding depression. Presumably because populations outside of Tangkoko are isolated, gene flow is minimized and there is a potential for inbreeding within groups where males cannot disperse because of habitat restrictions.
Threat: Human Disturbance
Ecotourism can be a way to integrate the goals of economic development with wildlife conservation, especially when involving charismatic species like the crested black macaque. When managed improperly, though, there can be negative effects on both wildlife and local communities as tourists disturb natural behaviors and exploit local people (Kinnaird & O’Brien 1996). In Tangkoko, the presence of large numbers of tourists has a negative effect on crested black macaque groups; they consistently run in fear, vocalize, and flee to the trees in the presence of more than five tourists (Kinnaird & O’Brien 1996).
Currently, there are no requirements for exploring Tangkoko, such as being accompanied by a trained guide, a factor that could seriously contribute to the stressful responses of crested black macaques to tourists. If groups of only a few individuals approached crested black macaques and were walking and talking loudly, the response was to flee (Kinnaird & O’Brien 1996). Requiring that a trained guide accompany tourists would decrease the chances of inappropriate behavior by visitors and decrease the disturbance of the monkeys. This would also create job opportunities for local people most familiar with the forest, and could even create an alternate income generating opportunity for hunters, who are skilled at tracking macaque groups. Carefully implemented and conscientious ecotourism operations could both increase revenues for local people and protect the crested black macaques in Tangkoko. Before this can occur, though, a change in the status of the reserve must be made, as tourism is currently illegal in Tangkoko. With the upgrade of the reserve to a park, the government would be able to increase gate fees, require guides, and initiate training to prepare for structured tours and these activities could increase the local economy and protection for crested black macaques (Kinnaird pers. comm.).
LINKS TO MORE ABOUT CONSERVATION
- No current links for Macaca nigra
- Links for all species
- Better Outlook for Dwindling Black Macaque Population in Indonesia (ScienceDaily; January 23, 2013)
- Links for all species
ORGANIZATIONS INVOLVED IN Macaca nigra CONSERVATION
Content last modified: February 2, 2006
Cite this page as:
Cawthon Lang KA. 2006 February 2. Primate Factsheets: Crested black macaque (Macaca nigra) Conservation . <http://pin.primate.wisc.edu/factsheets/entry/crested_black_macaque/cons>. Accessed 2020 July 30.
The following references were used in the writing of this factsheet. To find current references for Macaca nigra, search PrimateLit.
Anonymous. 1997. Fires of 1997. Sulawesi Prim News 4(2): 1-3.
Bernstein IS, Baker SC. 1988. Activity patterns in a captive group of Celebes black apes (Macaca nigra). Folia Primatol 51(2-3): 61-75.
Bynum EL. 1999. Biogeography and evolution of Sulawesi macaques. Trop Biodiv 6(1& 2): 19-36.
Bynum EL, Kohlhaas AK, Hadi Pramono A. 1999. Conservation status of Sulawesi macaques. Trop Biodiv 6(1& 2): 123-44.
Clayton L, Milner-Gulland EJ. 2000. The trade in wildlife in North Sulawesi, Indonesia. In: Robinson JG, Bennett EL, editors. Hunting for sustainability in tropical forests. New York: Columbia Univ Pr. p 473-96.
Feistner ATC. 2000. Wild population and current field research: conservation of Sulawesi crested black macaques Macaca nigra in Indonesia. In: Norcup SJ, compiler. Sulawesi crested black macaque Macaca nigra EEP Studbook No. 3. Jersey, Channel Islands (UK): Durrell Wildl Cons Trust. p 14-8.
Fujita K, Watanabe K. 1997. Discrimination of macaques by macaques: the case of Sulawesi species. Primates 38(3): 233-45.
Groves C. 2001. Primate taxonomy. Washington DC: Smithsonian Inst Pr. 350 p.
Hadidian J. 1980. Yawning in an old world monkey, Macaca nigra (Primates: Cercopithecidae). Behaviour 75: 133-47.
Kinnaird MF, O’Brien TG. 1996. Ecotourism in the Tangkoko DuaSudara Nature Reserve: opening Pandora’s box? Oryx 30(1): 65-73.
Kinnaird MF, O’Brien TG. 1999. A contextual analysis of the loud call of the Sulawesi crested black macaque, Macaca nigra. Tropic Biodiv 6(1& 2): 37-42.
Kinnaird MF, O’Brien TG. 2000. Comparative movement patterns of two semi-terrestrial cercopithecine primates: the Tana River crested mangabey and the Sulawesi crested black macaque. In: Boinski S, Garber PA, editors. On the move: how and why animals travel in groups. Chicago (IL): Univ Chicago Pr. p 327- 50.
Lee RJ. 1995. Population survey of the crested black macaque (Macaca nigra) at Manembonembo Nature Reserve in North Sulawesi, Indonesia. Prim Cons 16: 63-5.
Maestripieri D. 2004. Maternal behavior, infant handling, and socialization. In: Thierry B, Singh M, Kaumanns W, editors. Macaque societies: a model for the study of social organization. Cambridge (UK): Cambridge Univ Pr. p 231-4.
O’Brien TG, Kinnaird MF. 1996. Changing populations of birds and mammals in North Sulawesi. Oryx 30(2): 150-6.
O’Brien TG, Kinnaird MF. 1997. Behavior, diet, and movements of the Sulawesi crested black macaque (Macaca nigra). Int J Primatol 18(3): 321-51.
Reed C, O’Brien TG, Kinnaird MF. 1997. Male social behavior and dominance hierarchy in the Sulawesi crested black macaque (Macaca nigra). Int J Primatol 18(2): 247-60.
Rosenbaum B, O’Brien TG, Kinnaird M, Supriatna J. 1998b. Population densities of Sulawesi crested black macaques (Macaca nigra) on Bacan and Sulawesi, Indonesia: effects of habitat disturbance and hunting. Am J Primatol 44(2): 89-106.
Rosenbaum BR, Southwick CH, Supriatna J, Muskita Y, Yanuar A, Sinaga RM, Sapulette R. 1998a. A survey of population and habitat of the Sulawesi crested-black macaque (Macaca nigra) on Bacan Island, Maluku, Indonesia. Tropic Biodiv 5(2): 139-54.
Rowe N. 1996. The pictorial guide to the living primates. East Hampton (NY): Pogonias Pr. 263 p.
Siegert F, Ruecker G, Hinrichs A, Hoffmann AA. 2001. Increased damage from fires in logged forests during droughts caused by El Niño. Nature 414(6862): 437-40.
Singh M, Sinha A. 2004. Life history traits: ecological adaptations or phylogenetic relics? In: Thierry B, Singh M, Kaumanns W, editors. Macaque societies: a model for the study of social organization. Cambridge (UK): Cambridge Univ Pr. p 80-3.
Soltis J. 2004. Mating systems. In: Thierry B, Singh M, Kaumanns W, editors. Macaque societies: a model for the study of social organization. Cambridge (UK): Cambridge Univ Pr. p 135-54.
Thierry B, Bynum EL, Baker S, Kinnaird FM, Matsumura S, Muroyama Y, O’Brien TG, Petit O, Watanabe K. 2000. The social repertoire of Sulawesi macaques. Prim Res 16: 203-26.
Thomson JA, Hess DL, Dahl KD, Iliff-Sizemore SA, Stouffer RL, Wolf DP. 1992. The Sulawesi crested black macaque (Macaca nigra) menstrual cycle: changes in perineal tumescence and serum estradiol, progesterone, follicle-stimulating hormone, and luteinizing hormone levels. Biol Reprod 46: 879-84.
Watanabe K, Matsumura S. 1991. The borderlands and possible hybrids between three species of macaques, M. nigra, M. nigrescens, and M. hecki, in the northern peninsula of Sulawesi. Primates 32(3): 365-9.
Content last modified: February 2, 2006
Photo: Irwin S. Bernstein
Photo: Irwin S. Bernstein
Photo: Irwin S. Bernstein
Photo: Irwin S. Bernstein
Photo: Primates in Art & Illustration Collection
Photo: Robert H. Horwich
Photo: Robert H. Horwich
Photo: Robert H. Horwich
Primate Info Net (PIN) is maintained by the Wisconsin National Primate Research Center (WNPRC) at the University of Wisconsin-Madison, with countless grants and contributions from others over time. PIN is an ever-growing community effort: if you’d like to contribute, or have questions, please don’t hesitate to contact us.