Animal Diversity Web

Geographic Range

Arunachal macaques were discovered in Arunachal Pradesh, the easternmost state of India. They are most common in the region’s Tawang district, though they have also been observed in West Kameng (Sinha et al., 2005). They have never been documented outside of India, although some suspect they are found in neighboring Tibet and Bhutan. As of yet, this remains unconfirmed (Sinha et al., 2012). It is thought that the distribution of Arunachal macaques is bounded in the east by the Brahmaputra River. This would isolate it from a closely-related species, eastern Assamese macaques (Macaca assamensis) (Sinha et al., 2012). (Sinha, et al., 2005; Sinha, et al., 2012)

• Biogeographic Regions
• oriental
  • native

Habitat

Arunachal macaques are found exclusively in alpine regions, at altitudes of 2,000 to 3,500 meters. This is the highest elevation range of any Indian macaque (Sinha et al., 2005; Sinha et al., 2006). They are found in broadleaf forests, some of which are dense and some of which have been heavily degraded by human activity. Arunachal macaques are tolerant of such habitat modification and are often found in deforested/agricultural regions. This brings them into conflict with local villagers, whose crops they are known to raid and consume (Kumar et al., 2008). Arunachal macaques forage on the ground, but are still partially arboreal, preferring to nest in trees about 15 meters above the ground (Kumar, Mishra and Sinha, 2007; Kumar et al., 2008). (Kumar, et al., 2008a; Kumar, et al., 2007; Sinha, et al., 2005; Sinha, et al., 2006)

• Habitat Regions
• temperate
• terrestrial

• Terrestrial Biomes
• forest
• mountains

• Range elevation

  2000 to 3500 m

  6561.68 to 11482.94 ft

Physical Description

Arunachal macaques are large and stocky, with dark brown fur that lightens on the upper body and forelimbs (Sinha et al., 2005). The hair is long and dense, especially on the upper torso, and the short tail (around 39% to 45% of body length) distinguishes them from closely-related species (Mishra and Sinha, 2008). Arunachal macaques have dark ears, flaring noses, and light skin around the eyes. They have a distinctive yellow patch on the forehead, which contains a central whorl of dark hairs. Arunachal macaques often have a dark stripe above the eyes and a light-colored collar of hair around the neck (Sinha et al., 2005). Like many cercopithecines, Arunachal macaques are sexually dimorphic. Males are larger and bulkier than females, with longer skulls and more robust canines (Sinha et al., 2012). Aside from size, the species exhibits little age dimorphism. Juveniles are in most respects similar to adults, with a nearly identical appearance and coloration scheme. The most notable way to distinguish them is by their tails—which in juveniles are nearly-hairless and taper to a thin point (Sinha et al., 2005). Only one Arunachal macaque has been dissected and measured for study, and thus estimates of their dimensions are rough. All figures are based solely on the voucher specimen, which weighed 15 kilograms and measured 824 mm in length (560 head and body; 264 tail). This specimen, killed in a farmer’s trap, was an adult male. Females would likely have smaller measurements (Mishra and Sinha, 2008). No figures are available for the basal metabolic rate of Macaca munzala or for any closely-related species ("Macaca," 2002). ("Macaca", 2002; Mishra and Sinha, 2008; Sinha, et al., 2005; Sinha, et al., 2012)

• Other Physical Features
• homoiothermic

• Sexual Dimorphism
• male larger

• Average mass

  15 kg

  33.04 lb

• Average length

  824 mm

  32.44 in

Reproduction

The breeding system of Arunachal macaques is not well known. Several sexual behaviors have been observed in the species, including mounting and genital inspection. However, mating behaviors have never been specifically described (Kumar, Mishra and Sinha, 2007). Most closely related macaques are polygynous or polygynandrous, and Arunachal macaques may breed in the same way (Nowak, 1999). Their multimale-multifemale group structure indicates that this may be the case (Sinha et al., 2012). (Kumar, et al., 2007; Nowak, 1999; Sinha, et al., 2012)

• Mating System
• polygynous
• polygynandrous (promiscuous)

The average number of offspring, breeding season, birth mass, age at weaning, age at independence and age at sexual maturity of Arunachal macaques are all unknown. All discussion of the reproductive cycle is estimated, as the topic has never yet been studied. It is currently believed that Arunachal macaque females typically give birth every two years. Observed groups of Arunachal macaques have low infant-to-adult ratios, which may indicate they are not annual breeders. A two-year interbirth period would explain the discrepancy (Kumar et al. 2008). All macaques give birth to one or two young at once. Arunachal macaques should be no exception. The gestation period of other macaques varies, but is generally between 150 and 190 days. It is thus reasonable to assume that Arunachal macaque pregnancies are of similar length (Cawthon Lang, 2005). (Cawthon Lang, 2000; Kumar, et al., 2008a)

• Key Reproductive Features
• iteroparous
• viviparous

• Breeding interval

  Arunachal macaques are believed to breed every two years.

• Breeding season

  The breeding season of Arunachal macaques is unknown.

• Range number of offspring

  1 to 2

• Average number of offspring

  1

• Range gestation period

  150 to 190 days

Parental care in Arunachal macaques has yet to be formally described. However, some strong inferences can be made based on the behavior of related species. All primates have altricial young, which depend heavily on parental support. In macaques, this support is provided by the mother, who carries and nurses her infant throughout the first weeks of its life. Macaque mothers are also responsible for their babies’ feeding, grooming, learning, and protection (Thierry, 2007). In some macaque species, other individuals also play a role in young-rearing. These may include the mother’s older daughters or unrelated “aunts.” Males may also contribute to parenting on occasion, taking turns carrying and protecting infants (Theirry, 2007). It is unclear whether males play any parenting role among Arunachal macaques or whether “aunting” takes place, but such behaviors are possible and deserve investigation. (Thierry, 2007)

• Parental Investment
• altricial
• female parental care
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • provisioning
    • female
  • protecting
    • female
• post-independence association with parents

Lifespan/Longevity

The lifespan of Arunachal macaques has never been studied. It is likely, however, that it follows the pattern of its relatives. Most species in the genus Macaca live between 20 and 30 years in the wild. In captivity, many potential threats are eliminated, allowing them to live much longer. Captive individuals may reach 35 years, or sometimes even 40 (Cawthon Lang, 2005). (Cawthon Lang, 2000)

• Typical lifespan
  Status: wild

  20 to 30 years

• Typical lifespan
  Status: captivity

  30 to 40 years

Behavior

Arunachal macaques are social animals. They live in groups ranging in size from 5 to 60 individuals, with an average of 21.6 (Sinha et al., 2012). These groups contain males, females, juveniles, and infants, all of which coexist in a generally peaceful and cooperative manner. The group forages for food together during the day, and mutual social grooming is commonly observed. Adults most commonly groom members of the same sex and juveniles groom adult females. Antagonistic behaviors are rarely seen and are generally limited to threat displays. These threat displays are seen more commonly in the winter, when food supplies are scarcer and competition over them intensifies (Sinha et al., 2012). In general, macaques are highly social, with complex systems of dominance and hierarchy (Thierry, 2007). The group structure of Arunachal macaques, though it has yet to be specifically described, is likely no exception. Arunachal macaques have a matrifocal group structure and it is likely that the ranking of an individual macaque’s mother helps determine its future status (Sinha et al., 2012; Thierry, 2007). Arunachal macaques are diurnal, quadrupedal, and predominantly terrestrial. They are capable of climbing and spend their nights in the trees. During the day, they remain on the ground to forage. Arunachal macaques spend a significant amount of time feeding or seeking food. During the summer, feeding takes up 29 to 51% of their daily activity, and in winter this figure can rise to 41 to 66% (Mendiratta et al., 2009). Groups of Arunachal macaques have clearly defined home ranges, which may overlap. Macaques interact peacefully on the borders of these home ranges, which they rarely leave except for food acquisition. Within these ranges, macaques can travel long distances in search of a meal; foraging may account for 50% of the summer activity budget. During the winter, as they need to conserve energy, Arunachal macaques are less willing to travel. During this season they move infrequently, staying in one place and subsisting on larger quantities of lower-quality food (Mendiratta et al., 2009). Another energy-conserving measure employed by Arunachal macaques is resting. They spend more time resting than individuals of related species, most likely due to the colder temperatures and high altitudes of their habitat. During the day they frequently bask in the sun, spending a significant fraction of their time doing so (Sinha et al., 2012). Various miscellaneous behaviors have been observed in Arunachal macaques but not commented upon in detail. These include male branch-shaking (which probably serves as a dominance display), male-on-female sexual inspection, and male-on-male mounting (Sinha et al., 2012). (Mendiratta, et al., 2009; Sinha, et al., 2012; Thierry, 2007)

• Key Behaviors
• scansorial
• terricolous
• diurnal
• sedentary
• territorial
• social
• dominance hierarchies

• Range territory size

  0.07 to 0.55 km^2

Home Range

The home ranges of Arunachal macaques vary substantially, depending on group size, and are fairly loose in definition. Smaller groups may have diminutive ranges of 7 ha; larger groups may have ranges up to 55 ha in size. A particular group’s range use varies depending on the season. During the spring and summer, Arunachal macaques travel more in order to access food resources. During the winter, they are more inclined to stay in one place, subsisting on whatever resources can be locally found (Kumar, Mishra and Sinha, 2007; Mendiratta et al., 2009). (Kumar, et al., 2007; Mendiratta, et al., 2009)

Communication and Perception

Most macaques communicate both vocally and visually. Vocal communication, while never yet documented in Arunachal macaques, almost certainly exists and various visual displays are already known. These displays may include facial expression, body posture, and other behaviors such as branch-shaking. They usually communicate aggression or dominance-submission relationships. Tactile communication has also been observed in Arunachal macaques. As in many primates, grooming is a common social activity that promotes inter-individual bonding (Sinha et al., 2012). (Sinha, et al., 2012)

• Communication Channels
• visual
• tactile
• acoustic
• chemical

• Perception Channels
• visual
• acoustic

Food Habits

Arunachal macaques are almost exclusively herbivores, feeding on some 29 different plants. On occasion, they consume small invertebrates or mud, but the vast majority of the diet consists of leaves and pith. Other parts of the plant, such as fruit, flowers, stems, and bark, are also eaten on occasion (Mendiratta et al., 2009). The vast majority of the diet consists of only a few plants. Seven species make up 75% of their diet in the spring and two species comprise 75% of the winter diet, which is much less diverse and nutritious. During the winter, Arunachal macaques travel shorter distances to their food, subsisting on whatever lower-quality material they can find locally. They also switch from eating leaves and fruit to less-nutritious bark and pith (Mendiratta et al., 2009). The most important part of Arunachal macaque diet is a single plant, Erythrina variegata, which monopolizes over 72% of feeding time in the winter and around 19% in the spring. This plant is exceedingly common in the region where Arunachal macaques live and dominates the areas where they spend their winters (Mendiratta et al., 2009). (Mendiratta, et al., 2009)

• Primary Diet
• herbivore
  • folivore
  • lignivore

• Animal Foods
• insects
• terrestrial non-insect arthropods

• Plant Foods
• leaves
• wood, bark, or stems
• seeds, grains, and nuts
• fruit
• flowers
• sap or other plant fluids

Predation

Arunachal Pradesh, to which Arunachal macaques are confined, is home to several predators of medium to large size. These include dholes (Cuon alpinus), Asiatic black bears (Ursus thibetanus), and snow leopards (Uncia uncia). The dhole is known to hunt monkeys on occasion, and the other two can take prey of similar size. However, none of them are known predators of Arunachal macaques (Kumar et al., 2008; Chacon, 2000). Arunachal macaques are occasionally killed by humans, often in retaliation for crop destruction. They are not commonly eaten in most parts of their range, but may be hunted for use in traditional medicine. This makes Homo sapiens the only confirmed predator of Arunachal macaques (Sinha et al., 2006). (Chacon, 2000; Kumar, et al., 2008a; Sinha, et al., 2006)

• Known Predators

  • humans (Homo sapiens)

Ecosystem Roles

Arunachal macaques are occasional frugivores, though leaves, stems, bark, and pith comprise the greater part of their diet. They may serve as seed dispersers, as well as predators of the plants on which they feed. Arunachal macaques have no known predators or parasites besides humans, so it is difficult to further elaborate on their ecosystem role (Kumar et al., 2008). Further research should clarify their relationships with co-occurring species. (Kumar, et al., 2008a; Mendiratta, et al., 2009)

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

Any economic impact that Arunachal macaques have on humans is extremely small and localized. Locals of the Arunachal province occasionally hunt the species for use in traditional medicine (Kumar et al., 2008). They are rarely hunted for food or trophy purposes, though young individuals are sometimes captured and used as pets (Kumar et al., 2008; Radhakrishna et al., 2011). These are usually younger monkeys left behind during crop raids, after which they are kept in local villages. There is no major trade in Arunachal macaques as pet animals and the species is not bred in captivity (Radhakrishna et al., 2011). (Kumar, et al., 2008a; Radhakrishna, et al., 2011)

• Positive Impacts
• source of medicine or drug

Economic Importance for Humans: Negative

Arunachal macaques are known for highly destructive crop raids in which they steal wheat, millet, maize, barley, and fruit. They may also invade garbage dumps, kitchens, and granaries. Arunachal macaques are well-known pests to their human neighbors, who routinely list them among the most damaging sources of crop destruction. These macaques are often killed in retribution, usually with snares, bows, or guns (Sinha et al., 2005; Sinha et al., 2006). (Sinha, et al., 2005; Sinha, et al., 2006)

• Negative Impacts
• crop pest

Conservation Status

The IUCN Red List classifies Arunachal macaques as endangered, with a decreasing population trend. They are not commonly hunted for food, as they share portions of their range with the Buddhist Monpa people, who will not kill or eat them (Radhakrishna et al., 2011). However, their habitat is under threat from deforestation, and they are killed in retaliation for crop raids (Radhakrishna et al., 2011). Arunachal macaques are bold around humans, which contributes to their frequent conflict with them. Numbers of this species have never been high, with estimates of less than 600 individuals. Violent encounters with humans and habitat destruction put Arunachal macaques at great risk (Sinha et al., 2006). (Kumar, et al., 2008b; Radhakrishna, et al., 2011; Sinha, et al., 2006)

• IUCN Red List

  Endangered

• US Federal List

  No special status

• CITES

  Appendix II

Other Comments

Arunachal macaques are a recently described species about which little is known. They were named less than a decade ago, by Anindya Sinha and his colleagues (Sinha et al., 2005). They have since focused more research on the species, but few others have studied them. The validity of this species has been questioned in several studies (Kawamoto et al., 2006; Choudhury, 2008; Biswas et al., 2011). The authors of these studies do not recognize its taxonomic validity, citing DNA and morphological evidence. They believe that Arunachal macaques fall within the range of variation of their Assamese relative, Macaca assamensis.

The poverty of research on Macaca munzala also causes other problems. Many important facets of its lifestyle, including mating habits, lifespan, social structure, and ecological role, remain entirely undescribed. The information known about this species is spotty and greatly in need of expansion. Future research should resolve the many questions that surround this poorly known species. (Biswas, et al., 2011; Choudhury, 2008; Kawamoto, et al., 2006; Sinha, et al., 2005)

Contributors

Ethan France (author), Yale University, Eric Sargis (editor), Yale University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

2002. "Macaca" (On-line). AnAge: The Animal Ageing and Longevity Database. Accessed November 21, 2013 at http://genomics.senescence.info/species/query.php?search=macaca.

Biswas, J., D. Borah, A. Das, J. Das, P. Bhattacharjee, S. Mohnot, R. Horwich. 2011. The enigmatic Arunachal macaque: Its biogeography, biology and taxonomy in northeastern India. American Journal of Primatology, 73.5: 458-473.

Cawthon Lang, K. 2000. "Primate Factsheets" (On-line). Primate Info Net. Accessed December 10, 2013 at http://pin.primate.wisc.edu/factsheets/.

Chacon, R. 2000. "Cuon alpinus" (On-line). Animal Diversity Web. Accessed December 10, 2013 at http://animaldiversity.ummz.umich.edu/accounts/Cuon_alpinus/.

Choudhury, A. 2008. Primates of Bhutan and observations of hybrid langurs. Primate Conservation, 23: 65-73.

Kawamoto, Y., M. Aimi, T. Wangchuk, Sherub. 2006. Distribution of Assamese macaques (Macaca assamensis) in the inner Himalayan region of Bhutan and their mtDNA diversity. Primates, 47: 388-392.

Kumar, A., A. Sinha, S. Kumar. 2008. "Macaca munzala" (On-line). IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. www.iucnredlist.org. Accessed December 13, 2013 at http://www.iucnredlist.org/details/biblio/136569/0.

Kumar, R., N. Gama, R. Raghunath, A. Sinha, C. Mishra. 2008. In search of the munzala: distribution and conservation status of the newly-discovered Arunachal macaque Macaca munzala. Oryx, 42.3: 360-365.

Kumar, R., C. Mishra, A. Sinha. 2007. Foraging ecology and time-activity budget of the Arunachal macaque Macaca munzala – a preliminary study. Current Science, 93.4: 532-539.

Mendiratta, U., A. Kumar, C. Mishra, A. Sinha. 2009. Winter ecology of the Arunachal macaque Macaca munzala in Pangchen Valley, western Arunachal Pradesh, northeastern India. American Journal of Primatology, 71: 939-947.

Mishra, C., A. Sinha. 2008. A voucher specimen for Macaca munzala: interspecific affinities, evolution, and conservation of a newly discovered primate. International Journal of Primatology, 29: 743-756.

Nowak, R. 1999. Walker's Mammals of the World, Sixth Edition. Boston: Johns Hopkins University Press.

Radhakrishna, S., S. Daniel, L. Tania, S. Devi. 2011. "Distribution and concentration of Nycticebus bengalensis and Macaca munzala in Arunachal Pradesh, northeastern India" (On-line pdf). Rufford Foundation. Accessed November 12, 2013 at http://www.rufford.org/files/9452-1%20Detailed%20Final%20Report.pdf.

Sinha, A., R. Kumar, N. Gama, M. Madhusudan, C. Mishra. 2006. Distribution and conservation status of the Arunachal macaque, Macaca munzala, in western Arunachal Pradesh, northeastern India. Primate Conservation, 21: 145-148.

Sinha, A., D. Chakraborty, A. Datta, N. Gama, R. Kumar, M. Madhusudan, U. Mendiratta, U. Ramakrishnan, C. Mishra. 2012. Arunachal macaque Macaca munzala. Pp. 198-210 in A Johnsingh, N Manjrekar, eds. Mammals of South Asia, Vol. 1. Hyderabad, India: Universities Press.

Sinha, A., A. Datta, M. Madhusudan, C. Mishra. 2005. Macaca munzala: a new species from western Arunachal Pradesh, northeastern India. International Journal of Primatology, 26.4: 977-989.

Thierry, B. 2007. Unity in Diversity: Lessons From Macaque Societies. Evolutionary Anthropology, 16: 224-238. Accessed December 10, 2013 at http://www.clas.ufl.edu/users/krigbaum/proseminar/Thierry_MacaqueSocieties_EA_2007.pdf.