Francois' Langur - Habitat and Distribution

Habitat and Distribution

The preferred habitat of François' langur is a karst topography; limestone cliffs and caves of tropical and subtropical zones. By living on these limestone cliffs, the langur is at an advantage when it comes to sleeping arrangements. It sleeps either on ledges or in caves, with its preference being in the cave. François' langur has also been known to find sleeping sights in areas where the terrain is above 60 °F (16 °C), within evergreen forests. By living and sleeping in these limestone caves and cliffs, far from flat land, the langur has greatly reduced its rate of predation. It exhibits cryptic behavior and becomes very vigilant upon entry to the cave for final resting as a tactic to avoid any predators. In addition to this it also demonstrates a loud call to declare its territorial spacing. François' langur will also choose its sleeping habitat depending upon foraging availability. It will choose sleeping sites that are close to potential foraging sites, to maximize energy and reduce travel costs. It is important to note that sleeping sites are not located in the heart of foraging sites, but are within reasonable proximity, as the preferred nesting and foraging sites do not completely line up with one another. When it does go to forage, it tends to travel along the same route and returns to the same sleeping site consecutive nights to avoid predation. François' langur has been known to have approximately 6-10 regularly used sleeping sites that are used at various points throughout the year as water and food resources fluctuate.

François' langur has a restricted range of areas in which it can inhabit. It is primarily found in Southwest China and northern Vietnam. The majority of scientific studies of François' langur in the wild take place in the Nonggang Nature Reserve and the Fusui Nature Reserve in Guangxi Province, China. The average home range size of this species is 19 hectares (230,000 sq yd) and its day range size is 341–577 square metres (3,670–6,210 sq ft). In general, the low quality of its folivorous diet leads to nutritional stress, a smaller home range size and reduced daily travel time. The largest group of langurs reported numbered 500-600 individuals, and was found in the Mayanghe National Nature Reserve. The average group size is approximately 4-27. The Fusui Nature Reserve reported in 2009 that François' langur population had declined 73% in the previous 5 years, thus lessening their distribution even more. Recent census numbers have concluded that it is now limited to 14 localities in 10 different counties.