User:Igor071395/Mentawai langur

The Mentawai langur (Presbytis potenziani) is a species of primate in the family Cercopithecidae. It is endemic to the Mentawai Islands in Indonesia.

Its natural habitat is subtropical or tropical dry forests. It is threatened by habitat loss. The Siberut langur (P. siberu) was formerly considered a subspecies of the Mentawai langur...

Description
Mentawai langur infants undergoes change in coloration. They are born depigmented with a white pelage. After two to three weeks, the pelage begins to darken and the face becomes darkly pigmented. This change of coloration begins in the dorsal midline and head and ends laterally. After three months, the belly and chest are dark reddish-brown, throat, cheeks, forehead and tip of tail are white and the rest of the body is jet black. Males are differentiated from females by having a white circumgenital patch of fur. Mentawai langurs have a slender body with hide limbs longer than their forelimbs. Their social organisation is variable: unimale-unifemale, unimale-multifemale, multimale-multifemale.

Habitat
The Mentawai Islands of Indonesia are the homeplace of four endemic primates: simakobu monkey (Simias concolor), the Mentawai macaque (Macaca pagensis), Kloss's gibbon (Hylobates klossii) and the Mentawai langur (Presbytis potenziani). The Mentawai Islands have an area of about 7000km2 and there are a total of four islands: Siberut, Sipora, North and South Pagai. The climate in the islands is a humid tropical rainforest with high average rainfall of 4000mm per year. The Mentawai langur has two subspecies: P. potenziani siberu lives on Siberut, and P. p. potenziani lives on the southern islands of Sipora, North Pagai, and South Pagai. Siberut differs from the other islands by having extensive forest coverage and a low human population density. The Mentawai Islands peninsula is composed of two forest types: mixed primary forests and secondary forests. Dipterocarps are the most common tree type in the mixed primary forests, making 15% of all trees. The secondary forests are impacted by human disturbances where fallen trees cover the soil and a relatively low canopy is seen. Temperature range on the islands varies between 20-22 degrees celsius at night and 25-32 degrees celsius during daytime.

Habitat Use
Mentawai langurs use primary and secondary forests for their habitats. Most of habitat use by Mentawai langurs is located in primary forests. Four primary trees are used by Presbytis potenziani as a sleeping area: they are 35m in height and members of the family Dipterocarpaceae. The mid-upper levels of these trees are where Mentawai langurs sleep because that is where canopy density is the thickest. In general, these species spend their time in canopy height above 20m. Coconut groves, specifically, are most common sleeping sites for these species.

Ranging patterns
On average, groups of Presbytis potenziani have a daily ranging of 540m. Heavy rainfall affects movement patterns in groups of Presbytis potenziani. Light to moderate rainfall has no measurable affects on movement patterns. The most common form of locomotion in Presbytis potenziani is quadrupedal running and climbing. Leaping movement is done in mid and upper portions of canopy and drops occur nearer to the ground. Home range sizes varies between 11-40 ha. Presbytis potenziani groups are not migrants.

Activity budget
The activity budget of Mentawai langur is more than 80% of time spend for resting and foraging and a small portion is devoted to traveling and social behavior. The reason of such behavior is due to the diet. Extensive periods of resting and foraging is required for colobines that consumes seeds, unripe fruits and leaves to support digestion. In early mornings, the adult male moves away from the group and gives long calls.

Diet
Presbytis potenziani diet's consists primarily of seeds, unripe fruits and leaves. The feeding takes place in the upper portion of the canopy, above 20m in height. In a study by Fuentes, diet of Presbytis potenziani was found to be 55% leaves, 32% fruit and seed and 13% other source of food such as flowers, bark, sap and fungi. Diet in Mentawai langurs vary with habitat. Presbytis potenziani groups that use secondary forests for foraging have 70% of their diet coming from fruits and seeds and up to 35% of their diet consists of "climber" type vegetation. The niche breadth of Presbytis potenziani is 0.22, based on the Levin's index.

Conservation
According to the IUCN Red list, the Mentawai langur is currently critically endangered, based on criteria A2cd+4cd. Over the past 36 years, the population of Mentawai langur declined by 80%. The main threat to the monkey population is human population that hunts for food and destruction of the habitat (conversion to agriculture). 25% of hunting is on Mentawai langur by natives that live in the central-south Siberut. According to Eudey, there are four recommendations to conserve the species in the Mentawai Islands: development of the biosphere reserve on Siberut Island, creation of a primate reserve on South Pagai Island and offshore islands, survey of primates on Sipora Island and captive breeding program to recover the endemic subspecies of Mentawai primates on the southern islands, Sipora and Pagais. Whittaker recommends two conservation plans: increase existing protection and begin a campaign in education and law enforcement against hunting of Mentawai langurs on the Islands.