[3] Infants are born with bright orange coloured fur, which fades to black throughout the period of infancy lasting several months.

[7] One study investigated time distribution across activities in a disturbed environment, showing resting 35.41%, foraging 31.67%, traveling 14.44%, huddling 9.61%, playing 8.54%, and grooming 0.33%.

It also consumes fruits (17.2%), seeds (14.2%), flowers, stems, roots, bark, and occasionally minerals and insects from rock surfaces and cliffs.

Its diet includes Pithecellobium clypearia, Ficus nervosa, Garcinia pauncinervis, Sinosideroxylon pedunculatum, F. microcarpa, Miliusa chunni, Securidaca inappendiculata, Bauhinia sp., and Canthium dicoccum.

[10] The preferred habitat of François' langur is a karst topography; limestone cliffs and caves of tropical and subtropical zones.

[13] By living and sleeping in these limestone caves and cliffs, far from flat land, the langur has greatly reduced its rate of predation.

[12] 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.

[9] 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.

[3] The Fusui Nature Reserve reported in 2009 that François' langur population had declined 73% in the previous five years, thus lessening their distribution even more.

The langur lives on limestone cliffs, and when farmers look to cultivate their land, they light fires on the lower slopes.

[3] Limestone is particularly susceptible to fire; therefore, this practice not only destroys its habitats, but also causes major food shortages for the langur because its diet is primarily foliage.

Aerial predators such as the crested serpent eagle and the mountain hawk-eagle are a greater threat to François' langurs of Nonggang, especially to their young.

[12] Despite the extreme and continuing decline in the Francois' langur population, the actions being taken towards the conservation of this species and its habitat are still somewhat minimal.

[3] In 2003, the National Forestry Bureau acknowledged the rapid decline in François' langur and agreed to increase law enforcement in this area to help protect them from hunters.

[11] Finally, a current project is underway by the Global Environmental facility to protect the Nonggang National and Dmingshan Natural Reserves and the langurs living within.