Detailed Description:
Francois' Langur
From Wikipedia, the free encyclopedia
http://en.wikipedia.org/wiki/Francois%27_Langur
Conservation status: Endangered
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Cercopithecidae
Genus: Trachypithecus
Species group: T. francoisi
Species: T. francoisi
Binomial name: Trachypithecus francoisi
Range and Distribution
The Francois' langur has a restricted range of areas in which it can inhabit. They are primarily found in South West China and Northern Vietnam. A majority of the observations made on the Francois' langur 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 19ha and their day range size is 341-577m. In general, the low quality of their 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 Fusui nature Reserve reported in 2009 that the Francois' langur population had declined 73% in the previous 5 years, thus lessening their distribution even more.
Physical Deion
The Francois' langur is a medium sized primate with black silky hair. They grow to be approximately 24 inches tall with a tail length of approximately 33 inches. The average weight for an adult Francois' langur is 13-15 lbs. They have very distinct white sideburns that grow down from their ears to the corners of their cheeks. A morphological specialization of the Francois' langur is their complex stomach, made up of four separate chambers. This is a necessary adaptation for the digestion of their folivorous diet.
Social Structure
Francois' langurs tend to live in groups of four to seven langurs, the mean being seven. They live in harem societies with a group consisting of one male, three females, and three offspring. Within the society, the females will share parenting responsibilities with one another and are philopatric to the group.[8] Males within the group take no part in the raising of the young, the young males will leave the group before reaching sexual maturity.
Behavior
Francois' langurs are also sometimes referred to as “Leaf monkeys”. Over 50% of their diet is made up of young leaves. They will also consume fruits (17.2%), seeds, flowers, stems, roots, bark and occasionally minerals and insects off of rock surfaces and cliffs. These langurs consume their favorite food, young leaves, at the highest rate during the dry season, April through September, also known as the young leaf-lean period. The consumption of other dietary options for the langurs is typically consumed in the highest amounts during the months of October through March.
Langurs not only prefer young leaves, but also have been found to prefer plants of only 10 different species: Pithecellobium clypearia, Ficus nervosa, Garcinia pauncinervis, Sinosideroxylon pedunculatum, F. microcarpa, Miliusa chunni, Securidaca inappendiculata, bauhinia Sp., and Canthium dicoccum. Though these are the preferred plant species of the langur, they will still consume other plant species opportunistically.
Behavioral daily activities vary in the Francois' langur. Most of their time is spent resting and foraging year around. Traveling, playing, grooming and huddling are more dependent on the season. Interestingly it has been found that grooming happens in all of the seasons except the spring where it has been seen to not happen at all. Traveling is at its highest peak in the winter season, consuming 20.12% of their daily time budget. Lastly huddling is most prominent in the spring; it is most common to observe langurs spending approximately 14.62% of their time huddling.
Their preferred habitat is a karst topography; limestone cliffs and caves of tropical and subtropical zones. By living on these limestone cliffs, langurs are at an advantage when it comes to sleeping arrangements. Langurs sleep either on a ledge or in a cave, with their preference being in the cave. By living and sleeping in these limestone caves and cliffs, far from flat land, the langurs have greatly reduced their rate of predation. They exhibit cryptic behavior and become very vigilant upon entrance of the cave for final resting as a tactic to warn off any predators. In addition to this they also demonstrate a loud call to declare their territorial spacing. Francois' langurs will also choose their sleeping habitat depending upon foraging availability. They will choose sleeping sites that are close to potential foraging sites, to maximize energy and reduce travel costs. When they do go to forage they tend to travel along the same route and return to the same sleeping site for many consecutive nights to avoid predation.
Threats and Conservation
The population of the Francois' langur has been on a steady decline for the past 30 years. Of the many factors threatening the survival of the Francois' langur today, hunting has had one of the largest impacts. In Nonggang, where the Francois' langur is most prevalent, the natives believe that the langur had medicinal values, and have hunted them to make wine out of their bones, which they believed could cure fatigue and rheumatism. In 1983, the estimated population of the Francois' langur was 4,000-5,000. In the 1970's, hunting records recorded more than 1,400 langurs killed and in the 1980's more than 1,500 langurs were killed. Comparing these numbers it is evident how hunting had an enormous impact on the Francois' langur population.
Another threat to the Francois' langur is the destruction of their habitat. The langurs live on limestone cliffs and when farmers look to cultivate their land they will light fires on the lower slopes. Limestone is particularly susceptible to fire; therefore this practice not only destroys their habitats but also causes major food shortages for the langurs because their diet is primarily folivorous. The primary predators of the Francois' langur are both terrestrial and aerial. The clouded leopard is a potential predator to the langur but the clouded leopard's numbers are so low that they are not their greatest threat. Aerial predators such as Crescent Serpent Eagles and Mountain Hawk Eagles are a greater threat to the Francois' langurs of Nonggang, especially to their young.
The actions being taken towards the conservation of these animals and their habitat is still minimal. Their current population size is less than 2,500 individuals. A plan to protect the forest and ban hunting, called the Conservation Action Plan, was drafted in 1996 but has still yet to be implemented. In order to protect the langurs, not only does protection from hunting need to be implemented but their habitats must be protected as well. In 2003, the National Forestry Bureau acknowledged the rapid decline in the Francois langur and agreed to increase law enforcement in this area to help protect the langurs from hunters. In addition, the Asia Developmental Bank has begun helping the residents that live in close proximity to the habitats of the langurs build biogas facilities to reduce the fuel wood collection and thus possibly reduce the number of fires. And 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.