Macaca arctoides

Geographic Range

Stump-tailed macaques are native to southeast Asia. Their distribution includes China, India, Burma, West Malaysia, Thailand, Vietnam, eastern Bangladesh, and the Malay Peninsula. There is an introduced population in Tanaxpillo, Veracruz, Mexico, an island not inhabited by humans, where they live in conditions similar to their natural habitat in Asia.

• Biogeographic Regions
• nearctic nearctic
  • introduced introduced
• palearctic palearctic
  • native native

Habitat

Stump-tailed macaques are found in subtropical evergreen forests below 1500 m and tropical evergreen rainforests between 1800 and 2500 m. They live in wet environments and are not found in dry forests.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest
• rainforest rainforest

Physical Description

Stump-tailed macaques, also known as bear macaques, have shaggy, dark brown hair covering them. They have hairless faces with red skin which darkens with sun exposure. Infants are born with white hair that darkens as they age. As they age, adult males and females show balding on the tops of their heads, much like human males, receding from the forehead towards the back of the skull. As in all other cercopithecines , they have cheek pouches that they use to store food when foraging. They are terrestrial quadrupedal movers.

Stump-tailed macaques have hairless tails that are shorter than other g.Macaca species . Tail length ranges from 3.2 to 69 mm. This species is sexually dimorphic in many aspects of their physiology. Males are larger, ranging from 9.9 to 10.2 kg and 517 to 650 mm in height whereas females are 7.5 to 9.1 kg and 485 to 585 mm in height. Males also have much larger canines, which they use for asserting dominance within their group. Like all cercopithecids , they have a dental formula of: 2/2, 1/1, 2/2, 3/3.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger

Reproduction

Stump-tailed macaques are promiscuous in their mating behavior. Dominance plays a big role in who gets to mate. High ranking males monopolize females in the group. However, lower ranking males have other strategies of obtaining mating opportunities. They hang back and mate with females when the dominant male is not watching. Often referred to as the "sneaker" male strategy.

Both males and females initiate mating, though males tend to be more active when it comes to sexual behavior. Females make eye contact and present their perineal region (rump). Males approach females and sit next to them. Males chatter their teeth and grimace. When copulation is occurring, other group members often harass the pair.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

In their native habitat, stump-tail macaques breed during the months of October and November. In captivity they don't reproduce on any seasonal schedule. Females have an offspring about every 2 years. The gestation period is 177 days. After birth, infants are nursed for 9 months. After weaning they are still dependent on their mother and other adults in the group and don't reach independence until about 1.5 years old.

Young inherit rank maternally as females are philopatric. Male young disperse sometime after independence.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous

The primary caregiver for young is the mother. She nurses, carries, and protects them. Additionally, all the females in the group care for the young of other females, especially if the mother is high ranking. Females carry, play with, protect, and groom the young. Alpha males will also help protect young and infants since there is a good chance they are their offspring.

Stump-tailed macaques are more gentle with their young than other macaque species. Their is no threat of kidnapping from other group members, so mothers tend to be lenient with their young and give them independence in exploring the environment around them.

• Parental Investment
• precocial precocial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • male
    • female
• pre-independence
  • protecting
    • male
    • female
• post-independence association with parents
• extended period of juvenile learning
• maternal position in the dominance hierarchy affects status of young

Lifespan/Longevity

They can live up to 30 years in captivity. However, they tend to have shorter lifespans in the wild.

Behavior

Stump-tailed macaques live in groups of up to 60 individuals consisting of adult males, females, and young. Females are philopatric and males leave after sexual maturity. They are hierarchical, with rank being reinforced through physical contact such as biting and slapping. However, compared to other macaque species, they are more peaceful and egalitarian in their social structure. When young males move into a new group they fight to establish rank in the hierarchy. After a disagreement or fight they have a specific ritual of reconciliation. The subordinate will present his rump to the dominant male, who will kiss or embrace the subordinate. The subordinate will respond by "lip smacking" or "teeth chattering".

• Key Behaviors
• terricolous
• diurnal diurnal
• motile motile
• nomadic nomadic
• sedentary sedentary
• territorial territorial
• social social
• dominance hierarchies dominance hierarchies

Home Range

Territory size is unknown but is believed to be several square kilometers. During the day they travel 2 to 3 kilometers. They tend to travel less during the rainy season. After foraging during the day, they travel back to their sleeping sites in trees.

Communication and Perception

They communicate mostly visually and vocally. Common forms of visual communication are "teeth chattering", presenting one's rump to another individual, "lip smacking" and "barred teeth". When in heat, the females have swellings on their behind. This is a form of sexual communication, that they are receptive to mating.

Vocal communication often consists of "coo" which is used to stay in contact with other group members or when approaching another individual. They also use grunts when approaching another after fighting or if they are interested sexually. As mentioned before alpha males will "roar" to fend off predators.

When infants are distressed they will let out a shrill "whistle".

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic

• Other Communication Modes
• pheromones pheromones

• Perception Channels
• visual visual
• tactile tactile
• chemical chemical

Food Habits

Stump-tailed macaques have cheek pouches that, when filled, can hold a volume equal to that of their stomach. They forage starting in the morning through midday. They are omnivorous, but they eat mostly fruit. They also eat seeds, flowers, roots, leaves, and animals such as frogs, freshwater crabs, birds, and bird eggs. They have also been known to raid corn crops and cultivated fruits.

• Primary Diet
• herbivore herbivore
  • frugivore frugivore
• omnivore omnivore

• Animal Foods
• birds
• mammals
• amphibians
• reptiles
• eggs
• insects
• terrestrial worms
• aquatic crustaceans

• Plant Foods
• leaves
• roots and tubers
• seeds, grains, and nuts
• fruit
• flowers

• Foraging Behavior
• stores or caches food stores or caches food

Predation

Potential predators are large raptors, common leopards, dogs, and clouded leopards. To deter predators, they shake branches, bare their canines, assume aggressive postures, and alpha males will "roar".

Ecosystem Roles

Stump-tailed macaques contribution to native ecosystems as seed dispersers.

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

Humans have used stump-tailed macaques for testing the anti-hairloss drug minoxidil also known as Rogaine. By testing on the macaques, researchers were able to produce a safe product for human use.

• Positive Impacts
• research and education

Economic Importance for Humans: Negative

Stump-tailed macaques can be a nuisance for farmers by crop raiding.

• Negative Impacts
• crop pest

Conservation Status

On the IUCN list stum-tailed macaques are considered vulnerable. They are at risk for extinction in the near future. Their populations have decreased 20% in the last 10 years. There have already been instances of certain populations disappearing. Indian and Bangladesh populations haven't been seen since 1990. Habitat and hunting are the main causes and concerns for their conservation. They are also becoming more uncommon in Thailand and Malaysia. Human induced habitat change is the primary cause of population decline. Urban and agricultural expansion threatens native habitats. In India, where these macaques are legally protected, they have set aside areas of land for stump-tailed macaque conservation and are enforcing protection.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Charlotte Erfurth (author), University of Oregon, Stephen Frost (editor, instructor), University of Oregon.

References

Bauers, K., J. Hearn. 1994. Patterns of paternity in relation to male social rank in the stumptailed macaque, Macaca arctoides. Behaviour , 129(3-4): 149-176.

Brereton, A. 1994. Copulatory behavior in a free-ranging population of stumptail macaques (Macaca arctoides) in Mexico.. Primates , 35(2): 113-122.

Cerda-Molina, A., L. Hernández-López, S. Rojas-Maya, C. Murcia-Mejía, R. Mondragón-Ceballos. 2006. Male-Induced Sociosexual Behavior by Vaginal Secretions in Macaca arctoides.. International Journal of Primatology , 27/3: 791-807.

Chetry, D., R. Medhi, P. Bhattacharjee. 2003. Anti-predator behavior of stumptail macaques in Gibbon Wildlife Sanctuary, Assam, India.. Asian Primates , 8/4: 20-22.

Choudhury, A. 2002. Status and conservation of the stump-tailed macaque Macaca arctoides in India. Primate Rep , 63: 63-72.

Estrada, A., R. Estrada. 1984. Female-infant interactions among free-ranging stumptail macaques (Macaca arctoides).. Primates , 25(1): 48-61.

Fooden, J., Q. Guoqiang, W. Zongren, Yingxiang. 1985. The stumptail macaques of China.. American Journal of Primatology , 8(1): 11-30.

Fooden, J. 1990. The bear macaque, Macaca arctoides: a systematic review. Journal of Human Evolution , 19(6/7): 607-86.

Maestripieri, D. 1996. Social communication among captive stump-tailed macaques (Macaca arctoides). Int J Primatol , 17(5): 785-802.

Pertovaara, A., I. Linnankoski, D. Artchakov, P. Rämä, S. Carlson. 2004. A potential aphrodisiac for female macaques. Pharmacology, Biochemistry & Behavior; , 79/1: 137-141.

Uno, H. 1986. The stumptailed macaque as a model for baldness: effects of minoxidil.. International Journal of Cosmetic Science , 8/2: 288-296.