Pagai Island Macaque
The Pagai Island macaque (Macaca pagensis), also known as the Pagai macaque or Bokkoi, is an Old World monkey
Old World monkey
The Old World monkeys or Cercopithecidae are a group of primates, falling in the superfamily Cercopithecoidea in the clade Catarrhini. The Old World monkeys are native to Africa and Asia today, inhabiting a range of environments from tropical rain forest to savanna, shrubland and mountainous...

 that is endemic to the Mentawai Islands
Mentawai Islands
The Mentawai Islands are a chain of about seventy islands and islets off the western coast of Sumatra in Indonesia. Siberut is the largest of the islands. The other major islands are Sipura, North Pagai and South Pagai . The islands lie approximately 150 km off the Sumatran coast, across the...

 off the west coast of Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...

. It is listed as critically endangered
Critically endangered
Version 2010.3 of the IUCN Red List of Threatened Species identified 3744 Critically Endangered species, subspecies and varieties, stocks and subpopulations.Critically Endangered by kingdom:*1993 Animalia*2 Fungi*1745 Plantae*4 Protista-References:...

 on the IUCN Red List
IUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...

 due to its ever-shrinking habitat. It formerly included the overall darker M. siberu as a subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

, but this arrangement is polyphyletic, leading to the two being classified as separate species. Both were formerly considered subspecies of M. nemestrina.


Pagai Island macaque males are generally larger than females. The males' body length ranges from 45–55 cm and females' body length is around 40–45 cm. Tail length is 13–16 cm for males and 10–13 cm for females. Males are also heavier, weighing around 6–9 kg while females weigh 4.5–6 kg. Their backs have a dark brown coloration, and chestnut to pale ochre on the sides of the neck, the front of the shoulders and the underside of this species. Legs are brown and their arms, reddish brown. The face of a Mentawai Macaques is furless and black-skinned with brown eyes. They have cheek pouches to carry food while foraging.

Habitat and ecology

The macaques' natural habitat is rainforest
Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...

, but can also be found in riverine and coastal swamp
A swamp is a wetland with some flooding of large areas of land by shallow bodies of water. A swamp generally has a large number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types of swamp are "true" or swamp...

A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...

s. It lives high above the forest floor in the canopy, forages between 24 and 36 meters and may sleep as high as 45 meters. The primary diet of the species is fig
Ficus is a genus of about 850 species of woody trees, shrubs, vines, epiphytes, and hemiepiphyte in the family Moraceae. Collectively known as fig trees or figs, they are native throughout the tropics with a few species extending into the semi-warm temperate zone. The Common Fig Ficus is a genus of...

s. They may split up into splinter groups to forage for food and to sleep. They will eat alongside groups of Mentawai langur
Mentawai Langur
The Mentawai langur is a species of primate in the Cercopithecidae family. It is endemic to the Mentawai Islands in Indonesia.Its natural habitat is subtropical or tropical dry forests. It is threatened by habitat loss....

s. Macaca pagensis groups consist of around 5-25 indiviuals. There is typically a single male per group, along with adult females and their offspring. The male decides where to go and communicates this to the rest of the group with high-pitched cries. Roaming, solitary Pagai Island Macaques may challenge the dominant male for his position leading to aggressive fights. The natural predators of the species are the Crested Serpent Eagle
Crested Serpent Eagle
The Crested Serpent Eagle is a medium-sized bird of prey that is found in forested habitats across tropical Asia. Within its widespread range, there are considerable variations and some authorities prefer to treat several of its subspecies as completely separate species. In the past, several...

 and the Reticulated Python
Reticulated Python
Python reticulatus, also known as the reticulated python is a species of python found in Southeast Asia. Adults can grow to over 8.7 m in length but normally grow to an average of 3-6 m . They are the world's longest snakes and longest reptile, but are not the most heavily built...

. When spotted the macaques will alarm the rest of the group with a short, gruff bark.


Females show fertility and willingness to mate by displaying their swollen and reddened genitals. Females crouch to initiate mating. The gestation period is between 5 to 6 months. A single offspring is born during the nighttime hours. The mother eats the placenta
The placenta is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother's blood supply. "True" placentas are a defining characteristic of eutherian or "placental" mammals, but are also found in some snakes and...

 and licks the infant clean before morning. The mother and young share a close bond into adulthood.

Population and threats

The species' primary habitat is on the Mentawai Islands 150 km off the west coast of Sumatra. They populate three of the four major islands in the chain (North Pagai
North Pagai
North Pagai is one of the Mentawai Islands off the west coast of Sumatra in Indonesia. It is south of Sipura and north of South Pagai Island....

, South Pagai
South Pagai
South Pagai is one of the Mentawai Islands off the west coast of Sumatra in Indonesia. It is south of North Pagai Island...

 and Sipura
Sipura, or Sipora located off Sumatra in Indonesia, is the smallest and most developed of the four Mentawai Islands at only 845 km². The regency capital of the Mentawai Islands, Tua Pejat, is found on Sipora. An estimated 10-15% of the original rainforest remains on this island.Sipora is a...

). Due to deforestation
Deforestation is the removal of a forest or stand of trees where the land is thereafter converted to a nonforest use. Examples of deforestation include conversion of forestland to farms, ranches, or urban use....

 by immigrants from the Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...

n mainland the species is now listed as critically endangered on the IUCN red list. The primary reasons behind deforestation on the island are the clearing of large areas of land for cash crop
Cash crop
In agriculture, a cash crop is a crop which is grown for profit.The term is used to differentiate from subsistence crops, which are those fed to the producer's own livestock or grown as food for the producer's family...

 and oil palm
Oil palm
The oil palms comprise two species of the Arecaceae, or palm family. They are used in commercial agriculture in the production of palm oil. The African Oil Palm Elaeis guineensis is native to West Africa, occurring between Angola and Gambia, while the American Oil Palm Elaeis oleifera is native to...

A plantation is a long artificially established forest, farm or estate, where crops are grown for sale, often in distant markets rather than for local on-site consumption...

s, as well as commercial logging. As a result, the water levels in the forest rivers fluctuate to a much greater degree than before. The alternating flooding and low water levels has also caused an increase in the population of malaria
Malaria is a mosquito-borne infectious disease of humans and other animals caused by eukaryotic protists of the genus Plasmodium. The disease results from the multiplication of Plasmodium parasites within red blood cells, causing symptoms that typically include fever and headache, in severe cases...

l mosquito
Mosquitoes are members of a family of nematocerid flies: the Culicidae . The word Mosquito is from the Spanish and Portuguese for little fly...


External links

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