Mentawai langur
The Mentawai langur 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. The Siberut langur was formerly considered a subspecies of the Mentawai langur.
Description
Mentawai langur infants are born 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 hind limbs longer than their forelimbs.Distribution and habitat
Mentawai langurs are endemic to the islands of Sipora, North Pagai, and South Pagai. They inhabit primary and secondary forests dominated by dipterocarps. The trees used by Presbytis potenziani as sleeping areas are typically in height. The langurs sleep in the mid-upper levels of these trees above, where the canopy density is thickest, with the most common sites being in coconut groves.Behavior and diet
On average, groups of Mentawai langurs travel each day. Heavy rainfall affects movement patterns light to moderate rainfall does not. The langurs move by quadrupedal running and climbing; they also leap in the mid and upper portions of the canopy and drop when nearer to the ground. Home ranges vary from. The groups are not migrants. Their social organisation is variable: unimale-unifemale, unimale-multifemale, multimale-multifemale.Mentawai langurs spend more than 80% of their time resting and foraging and only a small portion traveling and conducting social behavior. Such extensive periods of resting and foraging are required for colobines that consume seeds, unripe fruits and leaves to support their digestion. Adult males typically move away from the group in the early morning and give long calls.
The langurs feed in the upper portion of the canopy. In some areas, their diet consists of 55% leaves, 32% fruit and seed and 13% other source of food such as flowers, bark, sap, and fungi. but groups that forage in secondary forests have a diet of 70% fruits and seeds and up to 35% "climber" type vegetation. The niche breadth of Presbytis potenziani is 0.22, based on Levin's index.